Answer: C

Explanation:

Source: TIPTON, Hal, (ISC)2, Introduction to the CISSP Exam presentation.

Answer: C

Explanation:

X.509 is used in digital certificates. X.400 is used in e-mail as a message handling protocol. X.25

is a standard for the network and data link levels of a communication network and X.75 is a

standard defining ways of connecting two X.25 networks.

Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten

Domains of Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (page 164).

Answer: C

Explanation:

An e-mail message's confidentiality is protected when encrypted with the receiver's public key,

because he is the only one able to decrypt the message. The sender is not supposed to have the

receiver's private key. By encrypting a message with its private key, anybody possessing the

corresponding public key would be able to read the message. By encrypting the message with its

public key, not even the receiver would be able to read the message.

Source: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 2002,

chapter 8: Cryptography (page 517).

Answer: D

Explanation:

A replay attack refers to the recording and retransmission of packets on the network. Kerberos

uses time stamps, which protect against this type of attack.

Source: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 2002,

chapter 8: Cryptography (page 581).

Answer: C

Explanation:

Output feedback (OFB) is a DES mode of operation, not input feedback.

Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten

Domains of Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (page 149).

Answer: B

Explanation:

The Pretty Good Privacy (PGP) email encryption system was developed by Phil Zimmerman. For

encrypting messages, it actually uses AES with up to 256-bit keys, CAST, TripleDES, IDEA and

Twofish. RSA is also used in PGP, but only for symmetric key exchange and for digital signatures,

but not for encryption.

Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten

Domains of Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (pages 154,

169).

More info on PGP can be found on their site at http://www.pgp.com/display.php?pageID=29.

Answer: A

Explanation:

MD5 is a one-way hash function producing a 128-bit message digest from the input message,

through 4 rounds of transformation. MD5 is specified as an Internet Standard (RFC1312).

Reference(s) used for this question:

TIPTON, Hal, (ISC)2, Introduction to the CISSP Exam presentation.

Answer: C

Explanation:

The Rijndael algorithm, chosen as the Advanced Encryption Standard (AES) to replace DES, can

be categorized as an iterated block cipher with a variable block length and key length that can be

independently chosen as 128, 192 or 256 bits.

Below you have a summary of the differences between AES and Rijndael.

AES is the advanced encryption standard defined by FIPS 197. It is implemented differently than

Rijndael:

FIPS-197 specifies that the block size must always be 128 bits in AES, and that the key size may

be either 128, 192, or 256 bits. Therefore AES-128, AES-192, and AES-256 are actually:

Key Size (bits) Number of rounds

Block Size (bits)

AES-128

128 10 Rounds

128

AES-192

192 12 Rounds

128

AES-256

256 14 Rounds

128

Some book will say "up to 9 rounds will be done with a 128 bits keys". Really it is 10 rounds

because you must include round zero which is the first round.

By contrast, the Rijndael specification per se is specified with block and key sizes that may be any

multiple of 32 bits, both with a minimum of 128 and a maximum of 256 bits.

Reference(s) used for this question:

KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of

Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (page 153).

and

FIPS 197

and

https://en.wikipedia.org/wiki/Advanced_Encryption_Standard

Answer: D

Explanation:

A Public Key Infrastructure (PKI) provides confidentiality, access control, integrity, authentication

and non-repudiation.

It does not provide reliability services.

Reference(s) used for this question:

TIPTON, Hal, (ISC)2, Introduction to the CISSP Exam presentation.

Answer: B

Explanation:

Public keys are published through digital certificates, signed by certification authority (CA), binding

the certificate to the identity of its bearer.

A bit more details:

Although “Digital Certificates” is the best (or least wrong!) in the list of answers presented, for the

past decade public keys have been published (ie: made known to the World) by the means of a

LDAP server or a key distribution server (ex.: http://pgp.mit.edu/). An indirect publishing method is

through OCSP servers (to validate digital signatures’ CRL)

Reference used for this question:

TIPTON, Hal, (ISC)2, Introduction to the CISSP Exam presentation.

and

http://technet.microsoft.com/en-us/library/dd361898.aspx

Answer: C

Explanation:

The above statement is NOT true and thus the correct answer. The maximum key size on Rijndael

is 256 bits.

There are some differences between Rijndael and the official FIPS-197 specification for AES.

Rijndael specification per se is specified with block and key sizes that must be a multiple of 32

bits, both with a minimum of 128 and a maximum of 256 bits. Namely, Rijndael allows for both key

and block sizes to be chosen independently from the set of { 128, 160, 192, 224, 256 } bits. (And

the key size does not in fact have to match the block size).

However, FIPS-197 specifies that the block size must always be 128 bits in AES, and that the key

size may be either 128, 192, or 256 bits. Therefore AES-128, AES-192, and AES-256 are actually:

Key Size (bits) Block Size (bits)

AES-128 128 128

AES-192 192 128

AES-256 256 128

So in short:

Rijndael and AES differ only in the range of supported values for the block length and cipher key

length.

For Rijndael, the block length and the key length can be independently specified to any multiple of

32 bits, with a minimum of 128 bits, and a maximum of 256 bits.

AES fixes the block length to 128 bits, and supports key lengths of 128, 192 or 256 bits only.

References used for this question:

http://blogs.msdn.com/b/shawnfa/archive/2006/10/09/the-differences-between-rijndael-andaes.aspx

and

http://csrc.nist.gov/CryptoToolkit/aes/rijndael/Rijndael.pdf

Answer: C

Explanation:

Split knowledge involves encryption keys being separated into two components, each of which

does not reveal the other. Split knowledge is the other complementary access control principle to

dual control.

In cryptographic terms, one could say dual control and split knowledge are properly implemented if

no one person has access to or knowledge of the content of the complete cryptographic key being

protected by the two rocesses.

The sound implementation of dual control and split knowledge in a cryptographic environment

necessarily means that the quickest way to break the key would be through the best attack known

for the algorithm of that key. The principles of dual control and split knowledge primarily apply to

access to plaintext keys.

Access to cryptographic keys used for encrypting and decrypting data or access to keys that are

encrypted under a master key (which may or may not be maintained under dual control and split

knowledge) do not require dual control and split knowledge. Dual control and split knowledge can

be summed up as the determination of any part of a key being protected must require the collusion

between two or more persons with each supplying unique cryptographic materials that must be

joined together to access the protected key.

Any feasible method to violate the axiom means that the principles of dual control and split

knowledge are not being upheld.

Split knowledge is the unique “what each must bring” and joined together when implementing dual

control. To illustrate, a box containing petty cash is secured by one combination lock and one

keyed lock. One employee is given the combination to the combo lock and another employee has

possession of the correct key to the keyed lock.

In order to get the cash out of the box both employees must be present at the cash box at the

same time. One cannot open the box without the other. This is the aspect of dual control.

On the other hand, split knowledge is exemplified here by the different objects (the combination to

the combo lock and the correct physical key), both of which are unique and necessary, that each

brings to the meeting. Split knowledge focuses on the uniqueness of separate objects that must be

joined together.

Dual control has to do with forcing the collusion of at least two or more persons to combine their

split knowledge to gain access to an asset. Both split knowledge and dual control complement

each other and are necessary functions that implement the segregation of duties in high integrity

cryptographic environments.

The following are incorrect answers:

Dual control is a procedure that uses two or more entities (usually persons) operating in concert to

protect a system resource, such that no single entity acting alone can access that resource. Dual

control is implemented as a security procedure that requires two or more persons to come

together and collude to complete a process. In a cryptographic system the two (or more) persons

would each supply a unique key, that when taken together, performs a cryptographic process.

Split knowledge is the other complementary access control principle to dual control.

Separation of duties - The practice of dividing the steps in a system function among different

individuals, so as to keep a single individual from subverting the process.

The need-to-know principle requires a user having necessity for access to, knowledge of, or

possession of specific information required to perform official tasks or services.

Reference(s) used for this question:

Schneiter, Andrew (2013-04-15). Official (ISC)2 Guide to the CISSP CBK, Third Edition :

Cryptography (Kindle Locations 1621-1635). . Kindle Edition.

and

Schneiter, Andrew (2013-04-15). Official (ISC)2 Guide to the CISSP CBK, Third Edition :

Cryptography (Kindle Locations 1643-1650). . Kindle Edition.

and

Shon Harris, CISSP All In One (AIO), 6th Edition , page 126

Answer: C

Explanation:

RC5 is a symmetric encryption algorithm. It is a block cipher of variable block length, encrypts

through integer addition, the application of a bitwise Exclusive OR (XOR), and variable rotations.

Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten

Domains of Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (page 153).

Answer: B

Explanation:

Users can obtain certificates with various levels of assurance. Here is a list that describe each of

them:

- Class 1/Level 1 for individuals, intended for email, no proof of identity

For example, level 1 certificates verify electronic mail addresses. This is done through the use of a

personal information number that a user would supply when asked to register. This level of

certificate may also provide a name as well as an electronic mail address; however, it may or may

not be a genuine name (i.e., it could be an alias). This proves that a human being will reply back if

you send an email to that name or email address.

- Class 2/Level 2 is for organizations and companies for which proof of identity is required

Level 2 certificates verify a user's name, address, social security number, and other information

against a credit bureau database.

- Class 3/Level 3 is for servers and software signing, for which independent verification and

checking of identity and authority is done by the issuing certificate authority

Level 3 certificates are available to companies. This level of certificate provides photo identification

to accompany the other items of information provided by a level 2 certificate.

- Class 4 for online business transactions between companies

- Class 5 for private organizations or governmental security

References:

http://en.wikipedia.org/wiki/Digital_certificate veriSign introduced the concept of classes of digital

certificates:

Also see:

Source: TIPTON, Harold F. & KRAUSE, Micki, Information Security Management Handbook, 4th

edition (volume 1), 2000, CRC Press, Chapter 3, Secured Connections to External Networks

(page 54).

Answer: C

Explanation:

On October 2, 2000, NIST announced the selection of the Rijndael Block Cipher, developed by the

Belgian cryptographers Dr. Joan Daemen and Dr. Vincent Rijmen, as the proposed AES

algorithm. Twofish and RC6 were also candidates. Blowfish is also a symmetric algorithm but

wasn't a finalist for a replacement for DES.

Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten

Domains of Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (page 152).

Answer: C

Explanation:

Block ciphers do not use public cryptography (private and public keys).

Block ciphers is a type of symmetric-key encryption algorithm that transforms a fixed-size block of

plaintext (unencrypted text) data into a block of ciphertext (encrypted text) data of the same length.

They are appropriate for software implementations and can operate internally as a stream. See

more info below about DES in Output Feedback Mode (OFB), which makes use internally of a

stream cipher.

The output feedback (OFB) mode makes a block cipher into a synchronous stream cipher. It

generates keystream blocks, which are then XORed with the plaintext blocks to get the ciphertext.

Just as with other stream ciphers, flipping a bit in the ciphertext produces a flipped bit in the

plaintext at the same location. This property allows many error correcting codes to function

normally even when applied before encryption.

Reference(s) used for this question:

Wikipedia on Block Cipher mode at: https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation

and

http://www.itl.nist.gov/fipspubs/fip81.htm

Answer: B

Explanation:

Steganography is a secret communication where the very existence of the message is hidden. For

example, in a digital image, the least significant bit of each word can be used to comprise a

message without causing any significant change in the image. Key clustering is a situation in

which a plaintext message generates identical ciphertext messages using the same transformation

algorithm but with different keys. Cryptology encompasses cryptography and cryptanalysis. The

Vernam Cipher, also called a one-time pad, is an encryption scheme using a random key of the

same size as the message and is used only once. It is said to be unbreakable, even with infinite

resources.

Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten

Domains of Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (page 134).

Answer: A

Explanation:

The purpose of a message authentication code - MAC is to verify both the source and message

integrity without the need for additional processes.

A MAC algorithm, sometimes called a keyed (cryptographic) hash function (however,

cryptographic hash function is only one of the possible ways to generate MACs), accepts as input

a secret key and an arbitrary-length message to be authenticated, and outputs a MAC (sometimes

known as a tag). The MAC value protects both a message's data integrity as well as its

authenticity, by allowing verifiers (who also possess the secret key) to detect any changes to the

message content.

MACs differ from digital signatures as MAC values are both generated and verified using the same

secret key. This implies that the sender and receiver of a message must agree on the same key

before initiating communications, as is the case with symmetric encryption. For the same reason,

MACs do not provide the property of non-repudiation offered by signatures specifically in the case

of a network-wide shared secret key: any user who can verify a MAC is also capable of generating

MACs for other messages.

In contrast, a digital signature is generated using the private key of a key pair, which is asymmetric

encryption. Since this private key is only accessible to its holder, a digital signature proves that a

document was signed by none other than that holder. Thus, digital signatures do offer nonrepudiation.

The following answers are incorrect:

PAM - Pluggable Authentication Module: This isn't the right answer. There is no known message

authentication function called a PAM. However, a pluggable authentication module (PAM) is a

mechanism to integrate multiple low-level authentication schemes and commonly used within the

Linux Operating System.

NAM - Negative Acknowledgement Message: This isn't the right answer. There is no known

message authentication function called a NAM. The proper term for a negative acknowledgement

is NAK, it is a signal used in digital communications to ensure that data is received with a

minimum of errors.

Digital Signature Certificate: This isn't right. As it is explained and contrasted in the explanations

provided above.

The following reference(s) was used to create this question:

The CCCure Computer Based Tutorial for Security+, you can subscribe at http://www.cccure.tv

and

http://en.wikipedia.org/wiki/Message_authentication_code

Answer: B

Explanation:

In cryptography, the one-time pad (OTP) is a type of encryption that is impossible to crack if used

correctly. Each bit or character from the plaintext is encrypted by a modular addition with a bit or

character from a secret random key (or pad) of the same length as the plaintext, resulting in a

ciphertext. If the key is truly random, at least as long as the plaintext, never reused in whole or

part, and kept secret, the ciphertext will be impossible to decrypt or break without knowing the key.

It has also been proven that any cipher with the perfect secrecy property must use keys with

effectively the same requirements as OTP keys. However, practical problems have prevented onetime pads from being widely used.

First described by Frank Miller in 1882, the one-time pad was re-invented in 1917 and patented a

couple of years later. It is derived from the Vernam cipher, named after Gilbert Vernam, one of its

inventors. Vernam's system was a cipher that combined a message with a key read from a

punched tape. In its original form, Vernam's system was vulnerable because the key tape was a

loop, which was reused whenever the loop made a full cycle. One-time use came a little later

when Joseph Mauborgne recognized that if the key tape were totally random, cryptanalysis would

be impossible.

The "pad" part of the name comes from early implementations where the key material was

distributed as a pad of paper, so the top sheet could be easily torn off and destroyed after use. For

easy concealment, the pad was sometimes reduced to such a small size that a powerful

magnifying glass was required to use it. Photos show captured KGB pads that fit in the palm of

one's hand, or in a walnut shell. To increase security, one-time pads were sometimes printed onto

sheets of highly flammable nitrocellulose so they could be quickly burned.

The following are incorrect answers:

A running key cipher uses articles in the physical world rather than an electronic algorithm. In

classical cryptography, the running key cipher is a type of polyalphabetic substitution cipher in

which a text, typically from a book, is used to provide a very long keystream. Usually, the book to

be used would be agreed ahead of time, while the passage to use would be chosen randomly for

each message and secretly indicated somewhere in the message.

The Running Key cipher has the same internal workings as the Vigenere cipher. The difference

lies in how the key is chosen; the Vigenere cipher uses a short key that repeats, whereas the

running key cipher uses a long key such as an excerpt from a book. This means the key does not

repeat, making cryptanalysis more difficult. The cipher can still be broken though, as there are

statistical patterns in both the key and the plaintext which can be exploited.

Steganography is a method where the very existence of the message is concealed. It is the art

and science of encoding hidden messages in such a way that no one, apart from the sender and

intended recipient, suspects the existence of the message. it is sometimes referred to as Hiding in

Plain Sight.

Cipher block chaining is a DES operating mode. IBM invented the cipher-block chaining (CBC)

mode of operation in 1976. In CBC mode, each block of plaintext is XORed with the previous

ciphertext block before being encrypted. This way, each ciphertext block depends on all plaintext

blocks processed up to that point. To make each message unique, an initialization vector must be

used in the first block.

Reference(s) used for this question:

HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 2002, chapter

8: Cryptography (page 555).

and

http://en.wikipedia.org/wiki/One-time_pad

http://en.wikipedia.org/wiki/Running_key_cipher

http://en.wikipedia.org/wiki/Cipher_block_chaining#Cipher-block_chaining_.28CBC.29

Answer: C

Explanation:

In link encryption, each entity has keys in common with its two neighboring nodes in the

transmission chain.

Thus, a node receives the encrypted message from its predecessor, decrypts it, and then re773

encrypts it with a new key, common to the successor node. Obviously, this mode does not provide

protection if anyone of the nodes along the transmission path is compromised.

Encryption can be performed at different communication levels, each with different types of

protection and implications. Two general modes of encryption implementation are link encryption

and end-to-end encryption.

Link encryption encrypts all the data along a specific communication path, as in a satellite link, T3

line, or telephone circuit. Not only is the user information encrypted, but the header, trailers,

addresses, and routing data that are part of the packets are also encrypted. The only traffic not

encrypted in this technology is the data link control messaging information, which includes

instructions and parameters that the different link devices use to synchronize communication

methods. Link encryption provides protection against packet sniffers and eavesdroppers.

In end-to-end encryption, the headers, addresses, routing, and trailer information are not

encrypted, enabling attackers to learn more about a captured packet and where it is headed.

Reference(s) used for this question:

Harris, Shon (2012-10-25). CISSP All-in-One Exam Guide, 6th Edition (pp. 845-846). McGraw-Hill.

And:

KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of

Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (page 132).

Answer: B

Explanation:

Key clustering happens when a plaintext message generates identical ciphertext messages using

the same transformation algorithm, but with different keys.

Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten

Domains of Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (page 130).

Answer: A

Explanation:

DSS provides Integrity, digital signature and Authentication, but does not provide Encryption.

Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten

Domains of Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (page 160).

Answer: A

Explanation:

Symmetric-key algorithms are a class of algorithms for cryptography that use the same

cryptographic keys for both encryption of plaintext (sender) and decryption of ciphertext (receiver).

The keys may be identical, in practice, they represent a shared secret between two or more

parties that can be used to maintain a private information link.

This requirement that both parties have access to the secret key is one of the main drawbacks of

symmetric key encryption, in comparison to public-key encryption. This is also known as secret

key encryption. In symmetric key cryptography, each end of the conversation must have the same

key or they cannot decrypt the message sent to them by the other party.

Symmetric key crypto is very fast but more difficult to manage due to the need to distribute the key

in a secure means to all parts needing to decrypt the data. There is no key management built

within Symmetric crypto.

PKI provides CIA - Confidentiality (Through encryption) Integrity (By guaranteeing that the

message hasn't change in transit) and Authentication (Non-repudiation). Symmetric key crypto

provides mostly Confidentiality.

The following answers are incorrect:

- PKI - Public Key Infrastructure: This is the opposite of symmetric key crypto. Each side in PKI

has their own private key and public key. What one key encrypt the other one can decrypt. You

make use of the receiver public key to communicate securely with a remote user. The receiver will

use their matching private key to decrypt the data.

- Diffie-Hellman: Sorry, this is an asymmetric key technique. It is used for key agreement over an

insecure network such as the Internet. It allows two parties who has never met to negotiate a

secret key over an insecure network while preventing Man-In-The-Middle (MITM) attacks.

- DSS - Digital Signature Standard: Sorry, this is an asymmetric key technique.

The following reference(s) was used to create this question:

To learn more about this QUESTION NO: s and 100% of the Security+ CBK, subscribe to our

Holistic Computer Based Tutorial (CBT) on our Learning Management System at:

http://www.cccure.tv

and

http://en.wikipedia.org/wiki/Symmetric-key_algorithm

Answer: D

Explanation:

A keyed hash also called a MAC (message authentication code) is used for integrity protection

and authenticity.

In cryptography, a message authentication code (MAC) is a generated value used to authenticate

a message. A MAC can be generated by HMAC or CBC-MAC methods. The MAC protects both a

message’s integrity (by ensuring that a different MAC will be produced if the message has

changed) as well as its authenticity, because only someone who knows the secret key could have

modified the message.

MACs differ from digital signatures as MAC values are both generated and verified using the same

secret key. This implies that the sender and receiver of a message must agree on the same key

before initiating communications, as is the case with symmetric encryption. For the same reason,

MACs do not provide the property of non-repudiation offered by signatures specifically in the case

of a network-wide shared secret key: any user who can verify a MAC is also capable of generating

MACs for other messages.

HMAC

When using HMAC the symmetric key of the sender would be concatenated (added at the end)

with the message. The result of this process (message + secret key) would be put through a

hashing algorithm, and the result would be a MAC value. This MAC value is then appended to the

message being sent. If an enemy were to intercept this message and modify it, he would not have

the necessary symmetric key to create a valid MAC value. The receiver would detect the

tampering because the MAC value would not be valid on the receiving side.

CBC-MAC

If a CBC-MAC is being used, the message is encrypted with a symmetric block cipher in CBC

mode, and the output of the final block of ciphertext is used as the MAC. The sender does not

send the encrypted version of the message, but instead sends the plaintext version and the MAC

attached to the message. The receiver receives the plaintext message and encrypts it with the

same symmetric block cipher in CBC mode and calculates an independent MAC value. The

receiver compares the new MAC value with the MAC value sent with the message. This method

does not use a hashing algorithm as does HMAC.

Cipher-Based Message Authentication Code (CMAC)

Some security issues with CBC-MAC were found and they created Cipher-Based Message

Authentication Code (CMAC) as a replacement. CMAC provides the same type of data origin

authentication and integrity as CBC-MAC, but is more secure mathematically. CMAC is a variation

of CBC-MAC. It is approved to work with AES and Triple DES. HMAC, CBC-MAC, and CMAC

work higher in the network stack and can identify not only transmission errors (accidental), but

also more nefarious modifications, as in an attacker messing with a message for her own benefit.

This means all of these technologies can identify intentional, unauthorized modifications and

accidental changes— three in one.

The following are all incorrect answers:

"Message non-repudiation" is incorrect.

Nonrepudiation is the assurance that someone cannot deny something. Typically, nonrepudiation

refers to the ability to ensure that a party to a contract or a communication cannot deny the

authenticity of their signature on a document or the sending of a message that they originated.

To repudiate means to deny. For many years, authorities have sought to make repudiation

impossible in some situations. You might send registered mail, for example, so the recipient

cannot deny that a letter was delivered. Similarly, a legal document typically requires witnesses to

signing so that the person who signs cannot deny having done so.

On the Internet, a digital signature is used not only to ensure that a message or document has

been electronically signed by the person that purported to sign the document, but also, since a

digital signature can only be created by one person, to ensure that a person cannot later deny that

they furnished the signature.

"Message confidentiality" is incorrect. The Message confidentiality is protected by encryption not

by hashing algorithms.

"Message interleave checking" is incorrect. This is a nonsense term included as a distractor.

Reference(s) used for this question:

Harris, Shon (2012-10-25). CISSP All-in-One Exam Guide, 6th Edition (p. 1384). McGraw-Hill.

Kindle Edition.

and

http://csrc.nist.gov/publications/nistpubs/800-38B/SP_800-38B.pdf

and

http://searchsecurity.techtarget.com/definition/nonrepudiation

and

https://en.wikipedia.org/wiki/Message_authentication_code

Answer: C

Explanation:

As when a hash algorithm is applied on a message , it produces a message digest.

The other answers are incorrect because :

A digital signature is a hash value that has been encrypted with a sender's private key.

A ciphertext is a message that appears to be unreadable.

A plaintext is a readable data.

Reference : Shon Harris , AIO v3 , Chapter-8 : Cryptography , Page : 593-594 , 640 , 648

Answer: C

Explanation:

As session key is a symmetric key that is used to encrypt messages between two users. A session

key is only good for one communication session between users.

For example , If Tanya has a symmetric key that she uses to encrypt messages between Lance

and herself all the time , then this symmetric key would not be regenerated or changed. They

would use the same key every time they communicated using encryption. However , using the

same key repeatedly increases the chances of the key being captured and the secure

communication being compromised. If , on the other hand , a new symmetric key were generated

each time Lance and Tanya wanted to communicate , it would be used only during their dialog and

then destroyed. if they wanted to communicate and hour later , a new session key would be

created and shared.

The other answers are not correct because :

Public Key can be known to anyone.

Private Key must be known and used only by the owner.

Secret Keys are also called as Symmetric Keys, because this type of encryption relies on each

user to keep the key a secret and properly protected.

REFERENCES:

SHON HARRIS , ALL IN ONE THIRD EDITION : Chapter 8 : Cryptography , Page : 619-620

Answer: A

Explanation:

As it provides much of the same functionality that RSA provides: digital signatures, secure key

distribution,and encryption. One differing factor is ECC’s efficiency. ECC is more efficient that RSA

and any other asymmetric algorithm.

The following answers are incorrect because :

RSA is incorrect as it is less efficient than ECC to be used in handheld devices.

SHA is also incorrect as it is a hashing algorithm.

RC4 is also incorrect as it is a symmetric algorithm.

Reference : Shon Harris AIO v3 , Chapter-8 : Cryptography , Page : 631 , 638.

Answer: B

Explanation:

In a ciphertext-only attack, the attacker has the ciphertext of several messages encrypted with the

same encryption algorithm. Its goal is to discover the plaintext of the messages by figuring out the

key used in the encryption process. In a known-plaintext attack, the attacker has the plaintext and

the ciphertext of one or more messages. In a chosen-ciphertext attack, the attacker can chose the

ciphertext to be decrypted and has access to the resulting plaintext.

Source: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 2002,

Chapter 8: Cryptography (page 578).

Answer: A

Explanation:

The basic power in cryptography is randomness. This uncertainty is why encrypted data is

unusable to someone without the key to decrypt.

Initialization Vectors are a used with encryption keys to add an extra layer of randomness to

encrypted data. If no IV is used the attacker can possibly break the keyspace because of patterns

resulting in the encryption process. Implementation such as DES in Code Book Mode (CBC)

would allow frequency analysis attack to take place.

In cryptography, an initialization vector (IV) or starting variable (SV)is a fixed-size input to a

cryptographic primitive that is typically required to be random or pseudorandom. Randomization is

crucial for encryption schemes to achieve semantic security, a property whereby repeated usage

of the scheme under the same key does not allow an attacker to infer relationships between

segments of the encrypted message. For block ciphers, the use of an IV is described by so-called

modes of operation. Randomization is also required for other primitives, such as universal hash

functions and message authentication codes based thereon.

It is define by TechTarget as:

An initialization vector (IV) is an arbitrary number that can be used along with a secret key for data

encryption. This number, also called a nonce, is employed only one time in any session.

The use of an IV prevents repetition in data encryption, making it more difficult for a hacker using a

dictionary attack to find patterns and break a cipher. For example, a sequence might appear twice

or more within the body of a message. If there are repeated sequences in encrypted data, an

attacker could assume that the corresponding sequences in the message were also identical. The

IV prevents the appearance of corresponding duplicate character sequences in the ciphertext.

The following answers are incorrect:

- Stream Cipher: This isn't correct. A stream cipher is a symmetric key cipher where plaintext digits

are combined with pseudorandom key stream to product cipher text.

- OTP - One Time Pad: This isn't correct but OTP is made up of random values used as key

material. (Encryption key) It is considered by most to be unbreakable but must be changed with a

new key after it is used which makes it impractical for common use.

- Ciphertext: Sorry, incorrect answer. Ciphertext is basically text that has been encrypted with key

material (Encryption key)

The following reference(s) was used to create this question:

For more details on this TOPIC and other QUESTION NO: s of the Security+ CBK, subscribe to

our Holistic Computer Based Tutorial (CBT) at http://www.cccure.tv

and

whatis.techtarget.com/definition/initialization-vector-IV

and

en.wikipedia.org/wiki/Initialization_vector

Answer: C

Explanation:

As it is an algorithm used for encryption and does not provide hashing functions , it is also

commonly implemented ' Stream Ciphers '.

The other answers are incorrect because :

SHA-1 was designed by NIST and NSA to be used with the Digital Signature Standard (DSS).

SHA was designed to be used in digital signatures and was developed when a more secure

hashing algorithm was required for U.S. government applications.

MD2 is a one-way hash function designed by Ron Rivest that creates a 128-bit message digest

value. It is not necessarily any weaker than the other algorithms in the "MD" family, but it is much

slower.

MD5 was also created by Ron Rivest and is the newer version of MD4. It still produces a 128-bit

hash, but the algorithm is more complex, which makes it harder to break.

Reference : Shon Harris , AIO v3 , Chapter - 8 : Cryptography , Page : 644 - 645

Answer: A

Explanation:

OTP or One Time Pad is considered unbreakable if the key is truly random and is as large as the

plaintext and never reused in whole or part AND kept secret.

In cryptography, a one-time pad is a system in which a key generated randomly is used only once

to encrypt a message that is then decrypted by the receiver using the matching one-time pad and

key. Messages encrypted with keys based on randomness have the advantage that there is

theoretically no way to "break the code" by analyzing a succession of messages. Each encryption

is unique and bears no relation to the next encryption so that some pattern can be detected.

With a one-time pad, however, the decrypting party must have access to the same key used to

encrypt the message and this raises the problem of how to get the key to the decrypting party

safely or how to keep both keys secure. One-time pads have sometimes been used when the both

parties started out at the same physical location and then separated, each with knowledge of the

keys in the one-time pad. The key used in a one-time pad is called a secret key because if it is

revealed, the messages encrypted with it can easily be deciphered.

One-time pads figured prominently in secret message transmission and espionage before and

during World War II and in the Cold War era. On the Internet, the difficulty of securely controlling

secret keys led to the invention of public key cryptography.

The biggest challenge with OTP was to get the pad security to the person or entity you wanted to

communicate with. It had to be done in person or using a trusted courrier or custodian. It certainly

did not scale up very well and it would not be usable for large quantity of data that needs to be

encrypted as we often time have today.

The following answers are incorrect:

- One time Cryptopad: Almost but this isn't correct. Cryptopad isn't a valid term in cryptography.

- Cryptanalysis: Sorry, incorrect. Cryptanalysis is the process of analyzing information in an effort

to breach the cryptographic security systems.

- PGP - Pretty Good Privacy: PGP, written by Phil Zimmermann is a data encryption and

decryption program that provides cryptographic privacy and authentication for data. Still isn't the

right answer though. Read more here about PGP.

The following reference(s) was used to create this question:

To get more info on this QUESTION NO: s or any QUESTION NO: s of Security+, subscribe to the

CCCure Holistic Security+ CBT available at: http://www.cccure.tv

and

http://users.telenet.be/d.rijmenants/en/otp.htm

and

http://en.wikipedia.org/wiki/One-time_pad

and

http://searchsecurity.techtarget.com/definition/one-time-pad

Answer: C

Explanation:

As protocol was introduced by Visa and Mastercard to allow for more credit card transaction

possibilities. It is comprised of three different pieces of software, running on the customer's PC (an

electronic wallet), on the merchant's Web server and on the payment server of the merchant's

bank. The credit card information is sent by the customer to the merchant's Web server, but it

does not open it and instead digitally signs it and sends it to its bank's payment server for

processing.

The following answers are incorrect because :

SSH (Secure Shell) is incorrect as it functions as a type of tunneling mechanism that provides

terminal like access to remote computers.

S/MIME is incorrect as it is a standard for encrypting and digitally signing electronic mail and for

providing secure data transmissions.

SSL is incorrect as it uses public key encryption and provides data encryption, server

authentication, message integrity, and optional client authentication.

Reference : Shon Harris AIO v3 , Chapter-8: Cryptography , Page : 667-669

Answer: A

Explanation:

When we encrypt data we are basically taking the plaintext information and applying some key

material or keystream and conducting something called an XOR or Exclusive-OR operation.

The symbol used for XOR is the following: This is a type of cipher known as a stream cipher.

The operation looks like this:

0101 0001 Plain text

0111 0011 Key stream

0010 0010 Output (ciphertext)

As you can see, it's not simple addition and the XOR Operation uses something called a truth

table that explains why 0+1=1 and 1+1=0.

The rules are simples, if both bits are the same the result is zero, if both bits are not the same the

result is one.

The following answers are incorrect:

- Bit Swapping: Incorrect. This isn't a known cryptographic operations.

- Logical NOR: Sorry, this isn't correct but is where only 0+0=1. All other combinations of 1+1, 1+0

equals 0. More on NOR here.

- Decryption: Sorry, this is the opposite of the process of encryption or, the process of applying the

keystream to the plaintext to get the resulting encrypted text.

The following reference(s) was used to create this question:

For more details on XOR and all other QUESTION NO: s of cryptography. Subscribe to our holistic

Security+ CBT tutorial at http://www.cccure.tv

and

http://en.wikipedia.org/wiki/Exclusive-or

and

http://en.wikipedia.org/wiki/Stream_cipher

Answer: B

Explanation:

Diffie and Hellman describe a means for two parties to agree upon a shared secret in such a way

that the secret will be unavailable to eavesdroppers. This secret may then be converted into

cryptographic keying material for other (symmetric) algorithms. A large number of minor variants of

this process exist. See RFC 2631 Diffie-Hellman Key Agreement Method for more details.

In 1976, Diffie and Hellman were the first to introduce the notion of public key cryptography,

requiring a system allowing the exchange of secret keys over non-secure channels. The DiffieHellman algorithm is used for key exchange between two parties communicating with each other,

it cannot be used for encrypting and decrypting messages, or digital signature.

Diffie and Hellman sought to address the issue of having to exchange keys via courier and other

unsecure means. Their efforts were the FIRST asymmetric key agreement algorithm. Since the

Diffie-Hellman algorithm cannot be used for encrypting and decrypting it cannot provide

confidentiality nor integrity. This algorithm also does not provide for digital signature functionality

and thus non-repudiation is not a choice.

NOTE: The DH algorithm is susceptible to man-in-the-middle attacks.

KEY AGREEMENT VERSUS KEY EXCHANGE

A key exchange can be done multiple way. It can be done in person, I can generate a key and

then encrypt the key to get it securely to you by encrypting it with your public key. A Key

Agreement protocol is done over a public medium such as the internet using a mathematical

formula to come out with a common value on both sides of the communication link, without the

ennemy being able to know what the common agreement is.

The following answers were incorrect:

All of the other choices were not correct choices

Reference(s) used for this question:

Shon Harris, CISSP All In One (AIO), 6th edition . Chapter 7, Cryptography, Page 812.

http://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exchange

http://www.google.com/patents?vid=4200770

Answer: A

Explanation:

When evidence from a crime is to be used in the prosecution of a criminal it is critical that you

follow the law when handling that evidence. Part of that process is called chain of custody and is

when you maintain proactive and documented control over ALL evidence involved in a crime.

Failure to do this can lead to the dismissal of charges against a criminal because if the evidence is

compromised because you failed to maintain of chain of custody.

A chain of custody is chronological documentation for evidence in a particular case, and is

especially important with electronic evidence due to the possibility of fraudulent data alteration,

deletion, or creation. A fully detailed chain of custody report is necessary to prove the physical

custody of a piece of evidence and show all parties that had access to said evidence at any given

time.

Evidence must be protected from the time it is collected until the time it is presented in court.

The following answers are incorrect:

- Locking the laptop in your desk: Even this wouldn't assure that the defense team would try to

challenge chain of custody handling. It's usually easy to break into a desk drawer and evidence

should be stored in approved safes or other storage facility.

- Making a disk image for examination: This is a key part of system forensics where we make a

disk image of the evidence system and study that as opposed to studying the real disk drive. That

could lead to loss of evidence. However if the original evidence is not secured than the chain of

custoday has not been maintained properly.

- Cracking the admin password with chntpw: This isn't correct. Your first mistake was to

compromise the chain of custody of the laptop. The chntpw program is a Linux utility to (re)set the

password of any user that has a valid (local) account on a Windows system, by modifying the

crypted password in the registry's SAM file. You do not need to know the old password to set a

new one. It works offline which means you must have physical access (i.e., you have to shutdown

your computer and boot off a linux floppy disk). The bootdisk includes stuff to access NTFS

partitions and scripts to glue the whole thing together. This utility works with SYSKEY and includes

the option to turn it off. A bootdisk image is provided on their website at

http://freecode.com/projects/chntpw .

The following reference(s) was used to create this question:

For more details and to cover 100% of the exam QUESTION NO: s, subscribe to our holistic

Security+ 2014 CBT Tutorial at: http://www.cccure.tv/

and

http://en.wikipedia.org/wiki/Chain_of_custody

and

http://www.datarecovery.com/forensic_chain_of_custody.asp

Answer: C

Explanation:

Named after its inventors Ron Rivest , Adi Shamir and Leonard Adleman is based on the difficulty

of factoring large prime numbers.

Factoring a number means representing it as the product of prime numbers. Prime numbers, such

as 2, 3, 5, 7, 11, and 13, are those numbers that are not evenly divisible by any smaller number,

except 1. A non-prime, or composite number, can be written as the product of smaller primes,

known as its prime factors. 665, for example is the product of the primes 5, 7, and 19. A number is

said to be factored when all of its prime factors are identified. As the size of the number increases,

the difficulty of factoring increases rapidly.

The other answers are incorrect because:

El Gamal is based on the discrete logarithms in a finite field.

Elliptic Curve Cryptosystems (ECCs) computes discrete logarithms of elliptic curves.

International Data Encryption Algorithm (IDEA) is a block cipher and operates on 64 bit blocks of

data and is a SYMMETRIC algorithm.

Reference : Shon Harris , AIO v3 , Chapter-8 : Cryptography , Page : 638

Answer: A

Explanation:

A one way hashing function can only be use for the integrity of a message and not for

authentication or confidentiality. Because the hash creates just a fingerprint of the message which

cannot be reversed and it is also very difficult to create a second message with the same hash.

A hash by itself does not provide Authentication. It only provides a weak form or integrity. It would

be possible for an attacker to perform a Man-In-The-Middle attack where both the hash and the

digest could be changed without the receiver knowing it.

A hash combined with your session key will produce a Message Authentication Code (MAC) which

will provide you with both authentication of the source and integrity. It is sometimes referred to as

a Keyed Hash.

A hash encrypted with the sender private key produce a Digital Signature which provide

authentication, but not the hash by itself.

Hashing functions by themselves such as MD5, SHA1, SHA2, SHA-3 does not provide

authentication.

Source: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 2001,

Page 548

Answer: B

Explanation:

Digital Signature Standard (DSS) specifies a Digital Signature Algorithm (DSA) appropriate for

applications requiring a digital signature, providing the capability to generate signatures (with the

use of a private key) and verify them (with the use of the corresponding public key).

Source: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 2002,

chapter 8: Cryptography (page 550).

Reference: DSS: http://www.itl.nist.gov/fipspubs/fip186.htm.

Answer: A

Explanation:

A chosen-ciphertext attack is one in which cryptanalyst may choose a piece of ciphertext and

attempt to obtain the corresponding decrypted plaintext. This type of attack is generally most

applicable to public-key cryptosystems.

A chosen-ciphertext attack (CCA) is an attack model for cryptanalysis in which the cryptanalyst

gathers information, at least in part, by choosing a ciphertext and obtaining its decryption under an

unknown key. In the attack, an adversary has a chance to enter one or more known ciphertexts

into the system and obtain the resulting plaintexts. From these pieces of information the adversary

can attempt to recover the hidden secret key used for decryption.

A number of otherwise secure schemes can be defeated under chosen-ciphertext attack. For

example, the El Gamal cryptosystem is semantically secure under chosen-plaintext attack, but this

semantic security can be trivially defeated under a chosen-ciphertext attack. Early versions of RSA

padding used in the SSL protocol were vulnerable to a sophisticated adaptive chosen-ciphertext

attack which revealed SSL session keys. Chosen-ciphertext attacks have implications for some

self-synchronizing stream ciphers as well. Designers of tamper-resistant cryptographic smart

cards must be particularly cognizant of these attacks, as these devices may be completely under

the control of an adversary, who can issue a large number of chosen-ciphertexts in an attempt to

recover the hidden secret key.

According to RSA:

Cryptanalytic attacks are generally classified into six categories that distinguish the kind of

information the cryptanalyst has available to mount an attack. The categories of attack are listed

here roughly in increasing order of the quality of information available to the cryptanalyst, or,

equivalently, in decreasing order of the level of difficulty to the cryptanalyst. The objective of the

cryptanalyst in all cases is to be able to decrypt new pieces of ciphertext without additional

information. The ideal for a cryptanalyst is to extract the secret key.

A ciphertext-only attack is one in which the cryptanalyst obtains a sample of ciphertext, without the

plaintext associated with it. This data is relatively easy to obtain in many scenarios, but a

successful ciphertext-only attack is generally difficult, and requires a very large ciphertext sample.

Such attack was possible on cipher using Code Book Mode where frequency analysis was being

used and even thou only the ciphertext was available, it was still possible to eventually collect

enough data and decipher it without having the key.

A known-plaintext attack is one in which the cryptanalyst obtains a sample of ciphertext and the

corresponding plaintext as well. The known-plaintext attack (KPA) or crib is an attack model for

cryptanalysis where the attacker has samples of both the plaintext and its encrypted version

(ciphertext), and is at liberty to make use of them to reveal further secret information such as

secret keys and code books.

A chosen-plaintext attack is one in which the cryptanalyst is able to choose a quantity of plaintext

and then obtain the corresponding encrypted ciphertext. A chosen-plaintext attack (CPA) is an

attack model for cryptanalysis which presumes that the attacker has the capability to choose

arbitrary plaintexts to be encrypted and obtain the corresponding ciphertexts. The goal of the

attack is to gain some further information which reduces the security of the encryption scheme. In

the worst case, a chosen-plaintext attack could reveal the scheme's secret key.

This appears, at first glance, to be an unrealistic model; it would certainly be unlikely that an

attacker could persuade a human cryptographer to encrypt large amounts of plaintexts of the

attacker's choosing. Modern cryptography, on the other hand, is implemented in software or

hardware and is used for a diverse range of applications; for many cases, a chosen-plaintext

attack is often very feasible. Chosen-plaintext attacks become extremely important in the context

of public key cryptography, where the encryption key is public and attackers can encrypt any

plaintext they choose.

Any cipher that can prevent chosen-plaintext attacks is then also guaranteed to be secure against

known-plaintext and ciphertext-only attacks; this is a conservative approach to security.

Two forms of chosen-plaintext attack can be distinguished:

Batch chosen-plaintext attack, where the cryptanalyst chooses all plaintexts before any of them

are encrypted. This is often the meaning of an unqualified use of "chosen-plaintext attack".

Adaptive chosen-plaintext attack, is a special case of chosen-plaintext attack in which the

cryptanalyst is able to choose plaintext samples dynamically, and alter his or her choices based on

the results of previous encryptions. The cryptanalyst makes a series of interactive queries,

choosing subsequent plaintexts based on the information from the previous encryptions.

Non-randomized (deterministic) public key encryption algorithms are vulnerable to simple

"dictionary"-type attacks, where the attacker builds a table of likely messages and their

corresponding ciphertexts. To find the decryption of some observed ciphertext, the attacker simply

looks the ciphertext up in the table. As a result, public-key definitions of security under chosenplaintext attack require probabilistic encryption (i.e., randomized encryption). Conventional

symmetric ciphers, in which the same key is used to encrypt and decrypt a text, may also be

vulnerable to other forms of chosen-plaintext attack, for example, differential cryptanalysis of block

ciphers.

An adaptive-chosen-ciphertext is the adaptive version of the above attack. A cryptanalyst can

mount an attack of this type in a scenario in which he has free use of a piece of decryption

hardware, but is unable to extract the decryption key from it.

An adaptive chosen-ciphertext attack (abbreviated as CCA2) is an interactive form of chosenciphertext attack in which an attacker sends a number of ciphertexts to be decrypted, then uses

the results of these decryptions to select subsequent ciphertexts. It is to be distinguished from an

indifferent chosen-ciphertext attack (CCA1).

The goal of this attack is to gradually reveal information about an encrypted message, or about the

decryption key itself. For public-key systems, adaptive-chosen-ciphertexts are generally applicable

only when they have the property of ciphertext malleability — that is, a ciphertext can be modified

in specific ways that will have a predictable effect on the decryption of that message.

A Plaintext Only Attack is simply a bogus detractor. If you have the plaintext only then there is no

need to perform any attack.

References:

RSA Laboratories FAQs about today's cryptography: What are some of the basic types of

cryptanalytic attack?

also see:

http://www.giac.org/resources/whitepaper/cryptography/57.php

and

http://en.wikipedia.org/wiki/Chosen-plaintext_attack

Answer: C

Explanation:

The answer above is the correct answer because it is FALSE. Rijndael does not support multiples

of 64 bits but multiples of 32 bits in the range of 128 bits to 256 bits. Key length could be 128, 160,

192, 224, and 256.

Both block length and key length can be extended very easily to multiples of 32 bits. For a total

combination of 25 different block and key size that are possible.

The Rijndael Cipher

Rijndael is a block cipher, designed by Joan Daemen and Vincent Rijmen as a candidate

algorithm for the Advanced Encryption Standard (AES) in the United States of America. The cipher

has a variable block length and key length.

Rijndael can be implemented very efficiently on a wide range of processors and in hardware.

The design of Rijndael was strongly influenced by the design of the block cipher Square.

The Advanced Encryption Standard (AES)

The Advanced Encryption Standard (AES) keys are defined to be either 128, 192, or 256 bits in

accordance with the requirements of the AES.

The number of rounds, or iterations of the main algorithm, can vary from 10 to 14 within the

Advanced Encryption Standard (AES) and is dependent on the block size and key length. 128 bits

keys uses 10 rounds or encryptions, 192 bits keys uses 12 rounds of encryption, and 256 bits keys

uses 14 rounds of encryption.

The low number of rounds has been one of the main criticisms of Rijndael, but if this ever

becomes a problem the number of rounds can easily be increased at little extra cost performance

wise by increasing the block size and key length.

Range of key and block lengths in Rijndael and AES

Rijndael and AES differ only in the range of supported values for the block length and cipher key

length.

For Rijndael, the block length and the key length can be independently specified to any multiple of

32 bits, with a minimum of 128 bits, and a maximum of 256 bits. The support for block and key

lengths 160 and 224 bits was introduced in Joan Daemen and Vincent Rijmen, AES submission

document on Rijndael, Version 2, September 1999 available at

http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf

AES fixes the block length to 128 bits, and supports key lengths of 128, 192 or 256 bits only.

Reference used for this question:

The Rijndael Page

and

http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf

and

FIPS PUB 197, Advanced Encryption Standard (AES), National Institute of Standards and

Technology, U.S. Department of Commerce, November 2001.

Answer: A

Explanation:

A cryptographic hash function is a transformation that takes an input (or 'message') and returns a

fixed-size string, which is called the hash value (sometimes termed a message digest, a digital

fingerprint, a digest or a checksum).

The ideal hash function has three main properties - it is extremely easy to calculate a hash for any

given data, it is extremely difficult or almost impossible in a practical sense to calculate a text that

has a given hash, and it is extremely unlikely that two different messages, however close, will

have the same hash.

Functions with these properties are used as hash functions for a variety of purposes, both within

and outside cryptography. Practical applications include message integrity checks, digital

signatures, authentication, and various information security applications. A hash can also act as a

concise representation of the message or document from which it was computed, and allows easy

indexing of duplicate or unique data files.

In various standards and applications, the two most commonly used hash functions are MD5 and

SHA-1. In 2005, security flaws were identified in both of these, namely that a possible

mathematical weakness might exist, indicating that a stronger hash function would be desirable. In

2007 the National Institute of Standards and Technology announced a contest to design a hash

function which will be given the name SHA-3 and be the subject of a FIPS standard.

A hash function takes a string of any length as input and produces a fixed length string which acts

as a kind of "signature" for the data provided. In this way, a person knowing the hash is unable to

work out the original message, but someone knowing the original message can prove the hash is

created from that message, and none other. A cryptographic hash function should behave as

much as possible like a random function while still being deterministic and efficiently computable.

A cryptographic hash function is considered "insecure" from a cryptographic point of view, if either

of the following is computationally feasible:

finding a (previously unseen) message that matches a given digest

finding "collisions", wherein two different messages have the same message digest.

An attacker who can do either of these things might, for example, use them to substitute an

authorized message with an unauthorized one.

Ideally, it should not even be feasible to find two messages whose digests are substantially

similar; nor would one want an attacker to be able to learn anything useful about a message given

only its digest. Of course the attacker learns at least one piece of information, the digest itself,

which for instance gives the attacker the ability to recognise the same message should it occur

again.

REFERENCES:

Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten

Domains of Computer Security, 2001, John Wiley & Sons, Pages 40-41.

also see:

http://en.wikipedia.org/wiki/Cryptographic_hash_function

Answer: B

Explanation:

SSL use public-key cryptography to secure session key, while the session key (secret key) is used

to secure the whole session taking place between both parties communicating with each other.

The SSL protocol was originally developed by Netscape. Version 1.0 was never publicly released;

version 2.0 was released in February 1995 but "contained a number of security flaws which

ultimately led to the design of SSL version 3.0." SSL version 3.0, released in 1996, was a

complete redesign of the protocol produced by Paul Kocher working with Netscape engineers Phil

Karlton and Alan Freier.

All of the other answers are incorrect

Answer: A

Explanation:

The computations involved in selecting keys and in enciphering data are complex, and are not

practical for manual use. However, using mathematical properties of modular arithmetic and a

method known as computing in Galois fields, RSA is quite feasible for computer use.

Source: FITES, Philip E., KRATZ, Martin P., Information Systems Security: A Practitioner's

Reference, 1993, Van Nostrand Reinhold, page 44.

Answer: B

Explanation:

Digital certificate helps others verify that the public keys presented by users are genuine and valid.

It is a form of Electronic credential proving that the person the certificate was issued to is who they

claim to be.

The certificate is used to identify the certificate holder when conducting electronic transactions.

It is issued by a certification authority (CA). It contains the name of an organization or individual,

the business address, a serial number, expiration dates, a copy of the certificate holder's public

key (used for encrypting messages), and the digital signature of the certificate-issuing authority so

that a recipient can verify that the certificate is real. Some digital certificates conform to a

standard, X.509. Digital certificates can be kept in registries so that authenticating users can look

up other users' public keys.

Digital certificates are key to the PKI process. The digital certificate serves two roles. First, it

ensures the integrity of the public key and makes sure that the key remains unchanged and in a

valid state. Second, it validates that the public key is tied to the stated owner and that all

associated information is true and correct. The information needed to accomplish these goals is

added into the digital certificate.

A Certificate Authority (CA) is an entity trusted by one or more users as an authority in a network

that issues, revokes, and manages digital certificates.

A Registration Authority (RA) performs certificate registration services on behalf of a CA. The RA,

a single purpose server, is responsible for the accuracy of the information contained in a certificate

request. The RA is also expected to perform user validation before issuing a certificate request.

A Digital Certificate is not like same as a digital signature, they are two different things, a digital

Signature is created by using your Private key to encrypt a message digest and a Digital

Certificate is issued by a trusted third party who vouch for your identity.

There are many other third parties which are providing Digital Certifictes and not just Verisign,

RSA.

Reference(s) used for this question:

Hernandez CISSP, Steven (2012-12-21). Official (ISC)2 Guide to the CISSP CBK, Third Edition

((ISC)2 Press) (Kindle Locations 14894-14903). Auerbach Publications. Kindle Edition.

Gregg, Michael; Haines, Billy (2012-02-16). CASP: CompTIA Advanced Security Practitioner

Study Guide Authorized Courseware: Exam CAS-001 (p. 24). Wiley. Kindle Edition.

Please refer to http://en.wikipedia.org/wiki/Digital_certificate

What is Digital certificate:

http://searchsecurity.techtarget.com/sDefinition/0,,sid14_gci211947,00.html

another deifination on http://www.webopedia.com/TERM/D/digital_certificate.html

Answer: C

Explanation:

Source: TIPTON, Hal, (ISC)2, Introduction to the CISSP Exam presentation.

Answer: B

Explanation:

Source: TIPTON, Hal, (ISC)2, Introduction to the CISSP Exam presentation.

Answer: A

Explanation:

An algorithm that turns messages or text into a fixed string of digits, usually for security or data

management purposes. The "one way" means that it's nearly impossible to derive the original text

from the string.

A one-way hash function is used to create digital signatures, which in turn identify and

authenticate the sender and message of a digitally distributed message.

A cryptographic hash function is a deterministic procedure that takes an arbitrary block of data and

returns a fixed-size bit string, the (cryptographic) hash value, such that an accidental or intentional

change to the data will change the hash value. The data to be encoded is often called the

"message," and the hash value is sometimes called the message digest or simply digest.

The ideal cryptographic hash function has four main or significant properties:

it is easy (but not necessarily quick) to compute the hash value for any given message

it is infeasible to generate a message that has a given hash

it is infeasible to modify a message without changing the hash

it is infeasible to find two different messages with the same hash

Cryptographic hash functions have many information security applications, notably in digital

signatures, message authentication codes (MACs), and other forms of authentication. They can

also be used as ordinary hash functions, to index data in hash tables, for fingerprinting, to detect

duplicate data or uniquely identify files, and as checksums to detect accidental data corruption.

Indeed, in information security contexts, cryptographic hash values are sometimes called (digital)

fingerprints, checksums, or just hash values, even though all these terms stand for functions with

rather different properties and purposes.

Source:

TIPTON, Hal, (ISC)2, Introduction to the CISSP Exam presentation.

and

http://en.wikipedia.org/wiki/Cryptographic_hash_function

Answer: A

Explanation:

RFC2828 (Internet Security Glossary) defines a known-plaintext attack as a cryptanalysis

technique in which the analyst tries to determine the key from knowledge of some plaintextciphertext pairs (although the analyst may also have other clues, such as the knowing the

cryptographic algorithm). A chosen-ciphertext attack is defined as a cryptanalysis technique in

which the analyst tries to determine the key from knowledge of plaintext that corresponds to

ciphertext selected (i.e., dictated) by the analyst. A chosen-plaintext attack is a cryptanalysis

technique in which the analyst tries to determine the key from knowledge of ciphertext that

corresponds to plaintext selected (i.e., dictated) by the analyst. The other choice is a distracter.

The following are incorrect answers:

A chosen-plaintext attacks

The attacker has the plaintext and ciphertext, but can choose the plaintext that gets encrypted to

see the corresponding ciphertext. This gives her more power and possibly a deeper understanding

of the way the encryption process works so she can gather more information about the key being

used. Once the key is discovered, other messages encrypted with that key can be decrypted.

A chosen-ciphertext attack

In chosen-ciphertext attacks, the attacker can choose the ciphertext to be decrypted and has

access to the resulting decrypted plaintext. Again, the goal is to figure out the key. This is a harder

attack to carry out compared to the previously mentioned attacks, and the attacker may need to

have control of the system that contains the cryptosystem.

A known-algorithm attack

Knowing the algorithm does not give you much advantage without knowing the key. This is a

bogus detractor. The algorithm should be public, which is the Kerckhoffs's Principle . The only

secret should be the key.

Reference(s) used for this question:

Source: SHIREY, Robert W., RFC2828: Internet Security Glossary, may 2000.

and

Harris, Shon (2012-10-25). CISSP All-in-One Exam Guide, 6th Edition (p. 866). McGraw-Hill.

Kindle Edition.

and

Kerckhoffs's Principle

Answer: A

Explanation:

The following are incorrect answers because they are all suitable methods.

A Delta CRL is a CRL that only provides information about certificates whose statuses have

changed since the issuance of a specific, previously issued CRL.

The Online Certificate Status Protocol (OCSP) is an Internet protocol used for obtaining the

revocation status of an X.509 digital certificate.

A Distribution point CRL or CRL Distribution Point, a location specified in the CRL Distribution

Point (CRL DP) X.509, version 3, certificate extension when the certificate is issued.

References:

RFC 2459: Internet X.509 Public Key Infrastru

http://csrc.nist.gov/groups/ST/crypto_apps_infra/documents/sliding_window.pdf

http://www.ipswitch.eu/online_certificate_status_protocol_en.html

Computer Security Handbook By Seymour Bosworth, Arthur E. Hutt, Michel E. Kabay

http://books.google.com/books?id=rCx5OfSFUPkC&printsec=frontcover&dq=Computer+Security+

Handbook#PRA6-PA4,M1

Answer: B

Explanation:

RFC 2828 (Internet Security Glossary) defines Simple Key Management for Internet Protocols

(SKIP) as:

A key distribution protocol that uses hybrid encryption to convey session keys that are used to

encrypt data in IP packets.

SKIP is an hybrid Key distribution protocol similar to SSL, except that it establishes a long-term

key once, and then requires no prior communication in order to establish or exchange keys on a

session-by-session basis. Therefore, no connection setup overhead exists and new keys values

are not continually generated. SKIP uses the knowledge of its own secret key or private

component and the destination's public component to calculate a unique key that can only be used

between them.

IKE stand for Internet Key Exchange, it makes use of ISAKMP and OAKLEY internally.

Internet Key Exchange (IKE or IKEv2) is the protocol used to set up a security association (SA) in

the IPsec protocol suite. IKE builds upon the Oakley protocol and ISAKMP. IKE uses X.509

certificates for authentication and a Diffie–Hellman key exchange to set up a shared session

secret from which cryptographic keys are derived.

The following are incorrect answers:

ISAKMP is an Internet IPsec protocol to negotiate, establish, modify, and delete security

associations, and to exchange key generation and authentication data, independent of the details

of any specific key generation technique, key establishment protocol, encryption algorithm, or

authentication mechanism.

IKE is an Internet, IPsec, key-establishment protocol (partly based on OAKLEY) that is intended

for putting in place authenticated keying material for use with ISAKMP and for other security

associations, such as in AH and ESP.

IPsec Key exchange (IKE) is only a detracto.

Reference(s) used for this question:

SHIREY, Robert W., RFC2828: Internet Security Glossary, may 2000.

and

http://en.wikipedia.org/wiki/Simple_Key-Management_for_Internet_Protocol

and

http://en.wikipedia.org/wiki/Simple_Key-Management_for_Internet_Protoco

Answer: D

Explanation:

The length of time between the Issuer’s receipt of a revocation request and the time the Issuer is

required to revoke the certificate should bear a reasonable relationship to the amount of risk the

participants are willing to assume that someone may rely on a certificate for which a proper

evocation request has been given but has not yet been acted upon.

How quickly revocation requests need to be processed (and CRLs or certificate status databases

need to be updated) depends upon the specific application for which the Policy Authority is rafting

the Certificate Policy.

A Policy Authority should recognize that there may be risk and lost tradeoffs with respect to grace

periods for revocation notices.

If the Policy Authority determines that its PKI participants are willing to accept a grace period of a

few hours in exchange for a lower implementation cost, the Certificate Policy may reflect that

decision.

Answer: A

Explanation:

RFC 2828 (Internet Security Glossary) defines IKE as an Internet, IPsec, key-establishment

protocol (partly based on OAKLEY) that is intended for putting in place authenticated keying

material for use with ISAKMP and for other security associations, such as in AH and ESP.

The following are incorrect answers:

SKIP is a key distribution protocol that uses hybrid encryption to convey session keys that are

used to encrypt data in IP packets.

The Key Exchange Algorithm (KEA) is defined as a key agreement algorithm that is similar to the

Diffie-Hellman algorithm, uses 1024-bit asymmetric keys, and was developed and formerly

classified at the secret level by the NSA.

Security Association Authentication Protocol (SAAP) is a distracter.

Reference(s) used for this question:

SHIREY, Robert W., RFC2828: Internet Security Glossary, may 2000.

Answer: D

Explanation:

RFC 2828 (Internet Security Glossary) defines OAKLEY as a key establishment protocol

(proposed for IPsec but superseded by IKE) based on the Diffie-Hellman algorithm and designed

to be a compatible component of ISAKMP.

ISAKMP is an Internet IPsec protocol to negotiate, establish, modify, and delete security

associations, and to exchange key generation and authentication data, independent of the details

of any specific key generation technique, key establishment protocol, encryption algorithm, or

authentication mechanism.

SKIP is a key distribution protocol that uses hybrid encryption to convey session keys that are

used to encrypt data in IP packets.

ISAKMP provides a framework for authentication and key exchange but does not define them.

ISAKMP is designed to be key exchange independant; that is, it is designed to support many

different key exchanges.

Oakley and SKEME each define a method to establish an authenticated key exchange. This

includes payloads construction, the information payloads carry, the order in which they are

processed and how they are used.

Oakley describes a series of key exchanges-- called modes and details the services provided by

each (e.g. perfect forward secrecy for keys, identity protection, and authentication).

SKEME describes a versatile key exchange technique which provides anonymity, repudiability,

and quick key refreshment.

RFC 2049 describes the IKE protocol using part of Oakley and part of SKEME in conjunction with

ISAKMP to obtain authenticated keying material for use with ISAKMP, and for other security

associations such as AH and ESP for the IETF IPsec DOI.

While Oakley defines "modes", ISAKMP defines "phases". The relationship between the two is

very straightforward and IKE presents different exchanges as modes which operate in one of two

phases.

Phase 1 is where the two ISAKMP peers establish a secure, authenticated channel with which to

communicate. This is called the ISAKMP Security Association (SA). "Main Mode" and "Aggressive

Mode" each accomplish a phase 1 exchange. "Main Mode" and "Aggressive Mode" MUST ONLY

be used in phase 1.

Phase 2 is where Security Associations are negotiated on behalf of services such as IPsec or any

other service which needs key material and/or parameter negotiation. "Quick Mode" accomplishes

a phase 2 exchange. "Quick Mode" MUST ONLY be used in phase 2.

References:

CISSP: Certified Information Systems Security Professional Study Guide By James Michael

Stewart, Ed Tittel, Mike Chappl, page 397

RFC 2049 at: http://www.ietf.org/rfc/rfc2409

SHIREY, Robert W., RFC2828: Internet Security Glossary, may 2000.

The All-in-one CISSP Exam Guide, 3rd Edition, by Shon Harris, page 674

The CISSP and CAP Prep Guide, Platinum Edition, by Krutz and Vines

Answer: B

Explanation:

RFC 2828 (Internet Security Glossary) defines the Internet Security Association and Key

Management Protocol (ISAKMP) as an Internet IPsec protocol to negotiate, establish, modify, and

delete security associations, and to exchange key generation and authentication data,

independent of the details of any specific key generation technique, key establishment protocol,

encryption algorithm, or authentication mechanism.

Let's clear up some confusion here first. Internet Key Exchange (IKE) is a hybrid protocol, it

consists of 3 "protocols"

ISAKMP: It's not a key exchange protocol per se, it's a framework on which key exchange

protocols operate. ISAKMP is part of IKE. IKE establishs the shared security policy and

authenticated keys. ISAKMP is the protocol that specifies the mechanics of the key exchange.

Oakley: Describes the "modes" of key exchange (e.g. perfect forward secrecy for keys, identity

protection, and authentication). Oakley describes a series of key exchanges and services.

SKEME: Provides support for public-key-based key exchange, key distribution centres, and

manual installation, it also outlines methods of secure and fast key refreshment.

So yes, IPSec does use IKE, but ISAKMP is part of IKE.

The questions did not ask for the actual key negotiation being done but only for the "exchange of

key generation and authentication data" being done. Under Oakly it would be Diffie Hellman (DH)

that would be used for the actual key nogotiation.

The following are incorrect answers:

Simple Key-management for Internet Protocols (SKIP) is a key distribution protocol that uses

hybrid encryption to convey session keys that are used to encrypt data in IP packets.

OAKLEY is a key establishment protocol (proposed for IPsec but superseded by IKE) based on

the Diffie-Hellman algorithm and designed to be a compatible component of ISAKMP.

IPsec Key Exchange (IKE) is an Internet, IPsec, key-establishment protocol [R2409] (partly based

on OAKLEY) that is intended for putting in place authenticated keying material for use with

ISAKMP and for other security associations, such as in AH and ESP.

Reference used for this question:

SHIREY, Robert W., RFC2828: Internet Security Glossary, may 2000.

Answer: B

Explanation:

RFC 2828 (Internet Security Glossary) defines digital watermarking as computing techniques for

inseparably embedding unobtrusive marks or labels as bits in digital data-text, graphics, images,

video, or audio#and for detecting or extracting the marks later. The set of embedded bits (the

digital watermark) is sometimes hidden, usually imperceptible, and always intended to be

unobtrusive. It is used as a measure to protect intellectual property rights. Steganography involves

hiding the very existence of a message. A digital signature is a value computed with a

cryptographic algorithm and appended to a data object in such a way that any recipient of the data

can use the signature to verify the data's origin and integrity. A digital envelope is a combination of

encrypted data and its encryption key in an encrypted form that has been prepared for use of the

recipient.

Source: SHIREY, Robert W., RFC2828: Internet Security Glossary, may 2000.

Answer: D

Explanation:

RFC 2828 (Internet Security Glossary) defines a digital signature as a value computed with a

cryptographic algorithm and appended to a data object in such a way that any recipient of the data

can use the signature to verify the data's origin and integrity.

The steps to create a Digital Signature are very simple:

1. You create a Message Digest of the message you wish to send

2. You encrypt the message digest using your Private Key which is the action of Signing

3. You send the Message along with the Digital Signature to the recipient

To validate the Digital Signature the recipient will make use of the sender Public Key. Here are the

steps:

1. The receiver will decrypt the Digital Signature using the sender Publick Key producing a clear

text message digest.

2. The receiver will produce his own message digest of the message received.

3. At this point the receiver will compare the two message digest (the one sent and the one

produce by the receiver), if the two matches, it proves the authenticity of the message and it

confirms that the message was not modified in transit validating the integrity as well. Digital

Signatures provides for Authenticity and Integrity only. There is no confidentiality in place, if you

wish to get confidentiality it would be needed for the sender to encrypt everything with the receiver

public key as a last step before sending the message.

A Digital Envelope is a combination of encrypted data and its encryption key in an encrypted form

that has been prepared for use of the recipient. In simple term it is a type of security that uses two

layers of encryption to protect a message. First, the message itself is encoded using symmetric

encryption, and then the key to decode the message is encrypted using public-key encryption.

This technique overcomes one of the problems of public-key encryption, which is that it is slower

than symmetric encryption. Because only the key is protected with public-key encryption, there is

very little overhead.

A cryptographic hash is the result of a cryptographic hash function such as MD5, SHA-1, or SHA2. A hash value also called a Message Digest is like a fingerprint of a message. It is used to

proves integrity and ensure the message was not changed either in transit or in storage.

A Message Authentication Code (MAC) refers to an ANSI standard for a checksum that is

computed with a keyed hash that is based on DES or it can also be produced without using DES

by concataning the Secret Key at the end of the message (simply adding it at the end of the

message) being sent and then producing a Message digest of the Message+Secret Key together.

The MAC is then attached and sent along with the message but the Secret Key is NEVER sent in

clear text over the network.

In cryptography, HMAC (Hash-based Message Authentication Code), is a specific construction for

calculating a message authentication code (MAC) involving a cryptographic hash function in

combination with a secret key. As with any MAC, it may be used to simultaneously verify both the

data integrity and the authenticity of a message. Any cryptographic hash function, such as MD5 or

SHA-1, may be used in the calculation of an HMAC; the resulting MAC algorithm is termed HMACMD5 or HMAC-SHA1 accordingly. The cryptographic strength of the HMAC depends upon the

cryptographic strength of the underlying hash function, the size of its hash output length in bits and

on the size and quality of the cryptographic key.

There is more than one type of MAC: Meet CBC-MAC

In cryptography, a Cipher Block Chaining Message Authentication Code, abbreviated CBC-MAC,

is a technique for constructing a message authentication code from a block cipher. The message

is encrypted with some block cipher algorithm in CBC mode to create a chain of blocks such that

each block depends on the proper encryption of the previous block. This interdependence ensures

that a change to any of the plaintext bits will cause the final encrypted block to change in a way

that cannot be predicted or counteracted without knowing the key to the block cipher.

References:

SHIREY, Robert W., RFC2828: Internet Security Glossary, may 2000.

and

http://www.webopedia.com/TERM/D/digital_envelope.html

and

http://en.wikipedia.org/wiki/CBC-MAC

Answer: C

Explanation:

A digital envelope for a recipient is a combination of encrypted data and its encryption key in an

encrypted form that has been prepared for use of the recipient.

It consists of a hybrid encryption scheme in sealing a message, by encrypting the data and

sending both it and a protected form of the key to the intended recipient, so that one else can open

the message.

In PKCS #7, it means first encrypting the data using a symmetric encryption algorithm and a

secret key, and then encrypting the secret key using an asymmetric encryption algorithm and the

public key of the intended recipient.

Source: SHIREY, Robert W., RFC2828: Internet Security Glossary, may 2000.

Answer: C

Explanation:

References: RFC 2459 : Internet X.509 Public Key Infrastructure Certificate and CRL Profile;

GUTMANN, P., X.509 style guide.

Answer: A

Explanation:

Cross-certification is the act or process by which two CAs each certifiy a public key of the other,

issuing a public-key certificate to that other CA, enabling users that are certified under different

certification hierarchies to validate each other's certificate.

Source: SHIREY, Robert W., RFC2828: Internet Security Glossary, may 2000.

Answer: C

Reference:
FORD, Warwick & BAUM, Michael S., Secure Electronic Commerce: Building the

Infrastructure for Digital Signatures and Encryption (2nd Edition), 2000, Prentice Hall PTR, Page

589; Directive 1999/93/EC of 13 December 1999 on a Community framework for electronic

signatures.

Answer: B

Explanation:

A certification authority (CA) is a third party entity that issues digital certificates (especially X.509

certificates) and vouches for the binding between the data items in a certificate. An issuing

authority could be considered a correct answer, but not the best answer, since it is too generic.

Source: SHIREY, Robert W., RFC2828: Internet Security Glossary, may 2000.

Answer: A

Explanation:

In cryptography, a public key certificate (or identity certificate) is an electronic document which

incorporates a digital signature to bind together a public key with an identity — information such as

the name of a person or an organization, their address, and so forth. The certificate can be used to

verify that a public key belongs to an individual.

In a typical public key infrastructure (PKI) scheme, the signature will be of a certificate authority

(CA). In a web of trust scheme, the signature is of either the user (a self-signed certificate) or other

users ("endorsements"). In either case, the signatures on a certificate are attestations by the

certificate signer that the identity information and the public key belong together.

In computer security, an authorization certificate (also known as an attribute certificate) is a digital

document that describes a written permission from the issuer to use a service or a resource that

the issuer controls or has access to use. The permission can be delegated.

Some people constantly confuse PKCs and ACs. An analogy may make the distinction clear. A

PKC can be considered to be like a passport: it identifies the holder, tends to last for a long time,

and should not be trivial to obtain. An AC is more like an entry visa: it is typically issued by a

different authority and does not last for as long a time. As acquiring an entry visa typically requires

presenting a passport, getting a visa can be a simpler process.

A real life example of this can be found in the mobile software deployments by large service

providers and are typically applied to platforms such as Microsoft Smartphone (and related),

Symbian OS, J2ME, and others.

In each of these systems a mobile communications service provider may customize the mobile

terminal client distribution (ie. the mobile phone operating system or application environment) to

include one or more root certificates each associated with a set of capabilities or permissions such

as "update firmware", "access address book", "use radio interface", and the most basic one,

"install and execute". When a developer wishes to enable distribution and execution in one of

these controlled environments they must acquire a certificate from an appropriate CA, typically a

large commercial CA, and in the process they usually have their identity verified using out-of-band

mechanisms such as a combination of phone call, validation of their legal entity through

government and commercial databases, etc., similar to the high assurance SSL certificate vetting

process, though often there are additional specific requirements imposed on would-be

developers/publishers.

Once the identity has been validated they are issued an identity certificate they can use to sign

their software; generally the software signed by the developer or publisher's identity certificate is

not distributed but rather it is submitted to processor to possibly test or profile the content before

generating an authorization certificate which is unique to the particular software release. That

certificate is then used with an ephemeral asymmetric key-pair to sign the software as the last step

of preparation for distribution. There are many advantages to separating the identity and

authorization certificates especially relating to risk mitigation of new content being accepted into

the system and key management as well as recovery from errant software which can be used as

attack vectors.

References:

HARRIS, Shon, All-In-One CISSP Certification Exam Guide, 2001, McGraw-Hill/Osborne, page

540.

http://en.wikipedia.org/wiki/Attribute_certificate

http://en.wikipedia.org/wiki/Public_key_cer tificate

Answer: C

Explanation:

The Internet Security Glossary (RFC2828) defines the Authority Revocation List (ARL) as a data

structure that enumerates digital certificates that were issued to CAs but have been invalidated by

their issuer prior to when they were scheduled to expire.

Do not to confuse with an ARL with a Certificate Revocation List (CRL). A certificate revocation list

is a mechanism for distributing notices of certificate revocations. The question specifically

mentions "issued to CAs" which makes ARL a better answer than CRL.

http://rfclibrary.hosting.com/rfc/rfc2828/rfc2828-29.asp

$ certificate revocation list (CRL)

(I) A data structure that enumerates digital certificates that have been invalidated by their issuer

prior to when they were

scheduled to expire. (See: certificate expiration, X.509 certificate revocation list.)

http://rfclibrary.hosting.com/rfc/rfc2828/rfc2828-17.asp

$ authority revocation list (ARL)

(I) A data structure that enumerates digital certificates that were issued to CAs but have been

invalidated by their issuer prior to when they were scheduled to expire. (See: certificate expiration,

X.509 authority revocation list.)

In a few words: We use CRL's for end-user cert revocation and ARL's for CA cert revocation - both

can be placed in distribution points.

Answer: D

Reference:
HARRIS, Shon, All-In-One CISSP Certification Exam Guide, 2001, McGrawHill/Osborne, page 139;

SNYDER, J., What is a SMART CARD?.

Wikipedia has a nice definition at: http://en.wikipedia.org/wiki/Tamper_resistance

Security

Tamper-resistant microprocessors are used to store and process private or sensitive information,

such as private keys or electronic money credit. To prevent an attacker from retrieving or

modifying the information, the chips are designed so that the information is not accessible through

external means and can be accessed only by the embedded software, which should contain the

appropriate security measures.

Examples of tamper-resistant chips include all secure cryptoprocessors, such as the IBM 4758

and chips used in smartcards, as well as the Clipper chip.

It has been argued that it is very difficult to make simple electronic devices secure against

tampering, because numerous attacks are possible, including:

physical attack of various forms (microprobing, drills, files, solvents, etc.)

freezing the device

applying out-of-spec voltages or power surges

applying unusual clock signals

inducing software errors using radiation

measuring the precise time and power requirements of certain operations (see power analysis)

Tamper-resistant chips may be designed to zeroise their sensitive data (especially cryptographic

keys) if they detect penetration of their security encapsulation or out-of-specification environmental

parameters. A chip may even be rated for "cold zeroisation", the ability to zeroise itself even after

its power supply has been crippled.

Nevertheless, the fact that an attacker may have the device in his possession for as long as he

likes, and perhaps obtain numerous other samples for testing and practice, means that it is

practically impossible to totally eliminate tampering by a sufficiently motivated opponent. Because

of this, one of the most important elements in protecting a system is overall system design. In

particular, tamper-resistant systems should "fail gracefully" by ensuring that compromise of one

device does not compromise the entire system. In this manner, the attacker can be practically

restricted to attacks that cost less than the expected return from compromising a single device

(plus, perhaps, a little more for kudos). Since the most sophisticated attacks have been estimated

to cost several hundred thousand dollars to carry out, carefully designed systems may be

invulnerable in practice

Answer: B

Explanation:

The Internet Security Glossary (RFC2828) defines an attribute certificate as a digital certificate

that binds a set of descriptive data items, other than a public key, either directly to a subject name

or to the identifier of another certificate that is a public-key certificate. A public-key certificate binds

a subject name to a public key value, along with information needed to perform certain

cryptographic functions. Other attributes of a subject, such as a security clearance, may be

certified in a separate kind of digital certificate, called an attribute certificate. A subject may have

multiple attribute certificates associated with its name or with each of its public-key certificates.

Source: SHIREY, Robert W., RFC2828: Internet Security Glossary, may 2000.

Answer: A

Explanation:

Remember the term Public-Key Certificate is synonymous with Digital Certificate or Identity

certificate.

The certificate itself provides the binding but it is the certificate authority who will go through the

Certificate Practice Statements (CPS) actually validating the bindings and vouch for the identity of

the owner of the key within the certificate.

As explained in Wikipedia:

In cryptography, a public key certificate (also known as a digital certificate or identity certificate) is

an electronic document which uses a digital signature to bind together a public key with an identity

— information such as the name of a person or an organization, their address, and so forth. The

certificate can be used to verify that a public key belongs to an individual.

In a typical public key infrastructure (PKI) scheme, the signature will be of a certificate authority

(CA). In a web of trust scheme such as PGP or GPG, the signature is of either the user (a selfsigned certificate) or other users ("endorsements") by getting people to sign each other keys. In

either case, the signatures on a certificate are attestations by the certificate signer that the identity

information and the public key belong together.

RFC 2828 defines the certification authority (CA) as:

An entity that issues digital certificates (especially X.509 certificates) and vouches for the binding

between the data items in a certificate.

An authority trusted by one or more users to create and assign certificates. Optionally, the

certification authority may create the user's keys.

X509 Certificate users depend on the validity of information provided by a certificate. Thus, a CA

should be someone that certificate users trust, and usually holds an official position created and

granted power by a government, a corporation, or some other organization. A CA is responsible

for managing the life cycle of certificates and, depending on the type of certificate and the CPS

that applies, may be responsible for the life cycle of key pairs associated with the certificates

Source: SHIREY, Robert W., RFC2828: Internet Security Glossary, may 2000.

and

http://en.wikipedia.org/wiki/Public_key_certificate

Answer: A

Explanation:

RFC 2459 : Internet X.509 Public Key Infrastructure Certificate and CRL Profile; GUTMANN, P.,

X.509 style guide; SMITH, Richard E., Internet Cryptography, 1997, Addison-Wesley Pub Co.

Answer: A

Explanation:

The Key management for IPSec is called the Internet Key Exchange (IKE)

Note: IKE underwent a series of improvements establishing IKEv2 with RFC 4306. The basis of

this answer is IKEv2.

The IKE protocol is a hybrid of three other protocols: ISAKMP (Internet Security Association and

Key Management Protocol), Oakley and SKEME. ISAKMP provides a framework for

authentication and key exchange, but does not define them (neither authentication nor key

exchange). The Oakley protocol describes a series of modes for key exchange and the SKEME

protocol defines key exchange techniques.

IKE—Internet Key Exchange. A hybrid protocol that implements Oakley and Skeme key

exchanges inside the ISAKMP framework. IKE can be used with other protocols, but its initial

implementation is with the IPSec protocol. IKE provides authentication of the IPSec peers,

negotiates IPSec keys, and negotiates IPSec security associations.

IKE is implemented in accordance with RFC 2409, The Internet Key Exchange.

The Internet Key Exchange (IKE) security protocol is a key management protocol standard that is

used in conjunction with the IPSec standard. IPSec can be configured without IKE, but IKE

enhances IPSec by providing additional features, flexibility, and ease of configuration for the IPSec

standard.

IKE is a hybrid protocol that implements the Oakley key exchange and the SKEME key exchange

inside the Internet Security Association and Key Management Protocol (ISAKMP) framework.

(ISAKMP, Oakley, and SKEME are security protocols implemented by IKE.)

IKE automatically negotiates IPSec security associations (SAs) and enables IPSec secure

communications without costly manual preconfiguration. Specifically, IKE provides these benefits:

•Eliminates the need to manually specify all the IPSec security parameters in the crypto maps at

both peers.

833

•Allows you to specify a lifetime for the IPSec security association.

•Allows encryption keys to change during IPSec sessions.

•Allows IPSec to provide anti-replay services.

•Permits certification authority (CA) support for a manageable, scalable IPSec implementation.

•Allows dynamic authentication of peers.

About ISAKMP

The Internet Security Association and Key Management Protocol (ISAKMP) is a framework that

defines the phases for establishing a secure relationship and support for negotiation of security

attributes, it does not establish sessions keys by itself, it is used along with the Oakley session key

establishment protocol. The Secure Key Exchange Mechanism (SKEME) describes a secure

exchange mechanism and Oakley defines the modes of operation needed to establish a secure

connection.

ISAKMP provides a framework for Internet key management and provides the specific protocol

support for negotiation of security attributes. Alone, it does not establish session keys. However it

can be used with various session key establishment protocols, such as Oakley, to provide a

complete solution to Internet key management.

About Oakley

The Oakley protocol uses a hybrid Diffie-Hellman technique to establish session keys on Internet

hosts and routers. Oakley provides the important security property of Perfect Forward Secrecy

(PFS) and is based on cryptographic techniques that have survived substantial public scrutiny.

Oakley can be used by itself, if no attribute negotiation is needed, or Oakley can be used in

conjunction with ISAKMP. When ISAKMP is used with Oakley, key escrow is not feasible.

The ISAKMP and Oakley protocols have been combined into a hybrid protocol. The resolution of

ISAKMP with Oakley uses the framework of ISAKMP to support a subset of Oakley key exchange

modes. This new key exchange protocol provides optional PFS, full security association attribute

negotiation, and authentication methods that provide both repudiation and non-repudiation.

Implementations of this protocol can be used to establish VPNs and also allow for users from

remote sites (who may have a dynamically allocated IP address) access to a secure network.

About IPSec

The IETF's IPSec Working Group develops standards for IP-layer security mechanisms for both

IPv4 and IPv6. The group also is developing generic key management protocols for use on the

Internet. For more information, refer to the IP Security and Encryption Overview.

IPSec is a framework of open standards developed by the Internet Engineering Task Force (IETF)

that provides security for transmission of sensitive information over unprotected networks such as

the Internet. It acts at the network level and implements the following standards:

IPSec

Internet Key Exchange (IKE)

Data Encryption Standard (DES)

MD5 (HMAC variant)

SHA (HMAC variant)

Authentication Header (AH)

Encapsulating Security Payload (ESP)

IPSec services provide a robust security solution that is standards-based. IPSec also provides

data authentication and anti-replay services in addition to data confidentiality services.

For more information regarding IPSec, refer to the chapter "Configuring IPSec Network Security."

About SKEME

SKEME constitutes a compact protocol that supports a variety of realistic scenarios and security

models over Internet. It provides clear tradeoffs between security and performance as required by

the different scenarios without incurring in unnecessary system complexity. The protocol supports

key exchange based on public key, key distribution centers, or manual installation, and provides

for fast and secure key refreshment. In addition, SKEME selectively provides perfect forward

secrecy, allows for replaceability and negotiation of the underlying cryptographic primitives, and

addresses privacy issues as anonymity and repudiatability

SKEME's basic mode is based on the use of public keys and a Diffie-Hellman shared secret

generation.

However, SKEME is not restricted to the use of public keys, but also allows the use of a preshared key. This key can be obtained by manual distribution or by the intermediary of a key

distribution center (KDC) such as Kerberos.

In short, SKEME contains four distinct modes:

Basic mode, which provides a key exchange based on public keys and ensures PFS thanks to

Diffie-Hellman.

A key exchange based on the use of public keys, but without Diffie-Hellman.

A key exchange based on the use of a pre-shared key and on Diffie-Hellman.

A mechanism of fast rekeying based only on symmetrical algorithms.

In addition, SKEME is composed of three phases: SHARE, EXCH and AUTH.

During the SHARE phase, the peers exchange half-keys, encrypted with their respective public

keys. These two half-keys are used to compute a secret key K. If anonymity is wanted, the

identities of the two peers are also encrypted. If a shared secret already exists, this phase is

skipped.

The exchange phase (EXCH) is used, depending on the selected mode, to exchange either DiffieHellman public values or nonces. The Diffie-Hellman shared secret will only be computed after the

end of the exchanges.

The public values or nonces are authenticated during the authentication phase (AUTH), using the

secret key established during the SHARE phase.

The messages from these three phases do not necessarily follow the order described above; in

actual practice they are combined to minimize the number of exchanged messages.

References used for this question:

Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten

Domains of Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (page 172).

http://tools.ietf.org/html/rfc4306

http://tools.ietf.org/html/rfc4301

http://en.wikipedia.org/wiki/Internet_Key_Exchange

CISCO ISAKMP and OAKLEY information

CISCO Configuring Internet Key Exchange Protocol

http://www.hsc.fr/ressources/articles/ipsec-tech/index.html.en

Answer: A

Explanation:

Content security measures presumes that the content is available in cleartext on the central mail

server.

Encrypted emails have to be decrypted before it can be filtered (e.g. to detect viruses), so you

need the decryption key on the central "crypto mail server".

There are several ways for such key management, e.g. by message or key recovery methods.

However, that would certainly require further processing in order to achieve such goal.

Answer: B

Explanation:

The main task here is the authentic distribution of the new root CA certificate as new trust anchor

to all the PKI participants (e.g. the users).

In some of the rollover-scenarios there is no automatic way, often explicit assignment of trust from

each user is needed, which could be very costly.

Other methods make use of the old root CA certificate for automatic trust establishment (see

PKIX-reference), but these solutions works only well for scenarios with currently valid root CA

certificates (and not for emergency cases e.g. compromise of the current root CA certificate).

The rollover of the root CA certificate is a specific and delicate problem and therefore are often

ignored during PKI deployment.

Reference: Camphausen, I.; Petersen, H.; Stark, C.: Konzepte zum Root CA Zertifikatswechsel,

conference Enterprise Security 2002, March 26-27, 2002, Paderborn; RFC 2459 : Internet X.509

Public Key Infrastructure Certificate and CRL Profile.

Answer: B

Explanation:

All of these statements pertaining to SSL are true except that it is primary use is to authenticate

the client to the server using public key cryptography and digital certificates. It is the opposite, Its

primary use is to authenticate the server to the client.

The following reference(s) were used for this question:

KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of

Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (page 170).

Answer: C

Explanation:

S/MIME (for Secure MIME, or Secure Multipurpose Mail Extension) is a security process used for

e-mail exchanges that makes it possible to guarantee the confidentiality and non-repudiation of

electronic messages.

S/MIME is based on the MIME standard, the goal of which is to let users attach files other than

ASCII text files to electronic messages. The MIME standard therefore makes it possible to attach

all types of files to e-mails.

S/MIME was originally developed by the company RSA Data Security. Ratified in July 1999 by the

IETF, S/MIME has become a standard, whose specifications are contained in RFCs 2630 to 2633.

How S/MIME works

The S/MIME standard is based on the principle of public-key encryption. S/MIME therefore makes

it possible to encrypt the content of messages but does not encrypt the communication.

The various sections of an electronic message, encoded according to the MIME standard, are

each encrypted using a session key.

The session key is inserted in each section's header, and is encrypted using the recipient's public

key. Only the recipient can open the message's body, using his private key, which guarantees the

confidentiality and integrity of the received message.

In addition, the message's signature is encrypted with the sender's private key. Anyone

intercepting the communication can read the content of the message's signature, but this ensures

the recipient of the sender's identity, since only the sender is capable of encrypting a message

(with his private key) that can be decrypted with his public key.

Reference(s) used for this question:

http://en.kioskea.net/contents/139-cryptography-s-mime

RFC 2630: Cryptographic Message Syntax;

OPPLIGER, Rolf, Secure Messaging with PGP and S/MIME, 2000, Artech House;

HARRIS, Shon, All-In-One CISSP Certification Exam Guide, 2001, McGraw-Hill/Osborne, page

570;

SMITH, Richard E., Internet Cryptography, 1997, Addison-Wesley Pub Co.

Answer: B

Explanation:

In order to protect against fraud in electronic fund transfers (EFT), the Message Authentication

Code (MAC), ANSI X9.9, was developed. The MAC is a check value, which is derived from the

contents of the message itself, that is sensitive to the bit changes in a message. It is similar to a

Cyclic Redundancy Check (CRC).

The aim of message authentication in computer and communication systems is to verify that he

message comes from its claimed originator and that it has not been altered in transmission. It is

particularly needed for EFT Electronic Funds Transfer). The protection mechanism is generation of

a Message Authentication Code (MAC), attached to the message, which can be recalculated by

the receiver and will reveal any alteration in transit. One standard method is described in (ANSI,

X9.9). Message authentication mechanisms an also be used to achieve non-repudiation of

messages.

The Secure Electronic Transaction (SET) was developed by a consortium including MasterCard

and VISA as a means of preventing fraud from occurring during electronic payment.

The Secure Hash Standard (SHS), NIST FIPS 180, available at

http://www.itl.nist.gov/fipspubs/fip180-1.htm, specifies the Secure Hash Algorithm (SHA-1).

Source:

KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of

Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (page 170)

also see:

http://luizfirmino.blogspot.com/2011/04/message-authentication-code-mac.html

and

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.22.2312&rep=rep1&type=pdf

Answer: A

Explanation:

More and more organizations are setting up their own internal PKIs. When these independent

PKIs need to interconnect to allow for secure communication to take place (either between

departments or different companies), there must be a way for the two root CAs to trust each other.

These two CAs do not have a CA above them they can both trust, so they must carry out cross

certification. A cross certification is the process undertaken by CAs to establish a trust relationship

in which they rely upon each other's digital certificates and public keys as if they had issued them

themselves.

When this is set up, a CA for one company can validate digital certificates from the other company

and vice versa.

Reference(s) used for this question:

For more information and illustration on Cross certification:

http://www.microsoft.com/technet/prodtechnol/windowsserver2003/technologies/security/ws03qsw

p.mspx http://www.entrust.com/resources/pdf/cross_certification.pdf

also see:

Shon Harris, CISSP All in one book, 4th Edition, Page 727

and

RFC 2459: Internet X.509 Public Key Infrastructure Certificate and CRL Profile; FORD, Warwick &

BAUM, Michael S., Secure Electronic Commerce: Building the Infrastructure for Digital Signatures

and Encryption (2nd Edition), 2000, Prentice Hall PTR, Page 254.

Answer: D

Explanation:

Other elements are included in a PKI.

Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten

Domains of Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (page 165).

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