Pass the ISC 2 Credentials SSCP Questions and answers with ValidTests

Computer worms are also known as Network Mobile Code, or a virus-like bit of code that can replicate itself over a network, infecting adjacent computers.

A computer worm is a standalone malware computer program that replicates itself in order to spread to other computers. Often, it uses a computer network to spread itself, relying on security failures on the target computer to access it. Unlike a computer virus, it does not need to attach itself to an existing program. Worms almost always cause at least some harm to the network, even if only by consuming bandwidth, whereas viruses almost always corrupt or modify files on a targeted computer.

A notable example is the SQL Slammer computer worm that spread globally in ten minutes on January 25, 2003. I myself came to work that day as a software tester and found all my SQL servers infected and actively trying to infect other computers on the test network.

A patch had been released a year prior by Microsoft and if systems were not patched and exposed to a 376 byte UDP packet from an infected host then system would become compromised.

Ordinarily, infected computers are not to be trusted and must be rebuilt from scratch but the vulnerability could be mitigated by replacing a single vulnerable dll called sqlsort.dll.

Replacing that with the patched version completely disabled the worm which really illustrates to us the importance of actively patching our systems against such network mobile code.

The following answers are incorrect:

- Rootkit: Sorry, this isn't correct because a rootkit isn't ordinarily classified as network mobile code like a worm is. This isn't to say that a rootkit couldn't be included in a worm, just that a rootkit isn't usually classified like a worm. A rootkit is a stealthy type of software, typically malicious, designed to hide the existence of certain processes or programs from normal methods of detection and enable continued privileged access to a computer. The term rootkit is a concatenation of "root" (the traditional name of the privileged account on Unix operating systems) and the word "kit" (which refers to the software components that implement the tool). The term "rootkit" has negative connotations through its association with malware.

- Adware: Incorrect answer. Sorry but adware isn't usually classified as a worm. Adware, or advertising-supported software, is any software package which automatically renders advertisements in order to generate revenue for its author. The advertisements may be in the user interface of the software or on a screen presented to the user during the installation process. The functions may be designed to analyze which Internet sites the user visits and to present advertising pertinent to the types of goods or services featured there. The term is sometimes used to refer to software that displays unwanted advertisements.

- Logic Bomb: Logic bombs like adware or rootkits could be spread by worms if they exploit the right service and gain root or admin access on a computer.

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

The CCCure CompTIA Holistic Security+ Tutorial and CBT

and

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

and

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

and

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

XSS or Cross-Site Scripting is a threat to web applications where malicious code is placed on a website that attacks the use using their existing authenticated session status.

Cross-Site Scripting attacks are a type of injection problem, in which malicious scripts are injected into the otherwise benign and trusted web sites. Cross-site scripting (XSS) attacks occur when an attacker uses a web application to send malicious code, generally in the form of a browser side script, to a different end user. Flaws that allow these attacks to succeed are quite widespread and occur anywhere a web application uses input from a user in the output it generates without validating or encoding it.

An attacker can use XSS to send a malicious script to an unsuspecting user. The end user’s browser has no way to know that the script should not be trusted, and will execute the script. Because it thinks the script came from a trusted source, the malicious script can access any cookies, session tokens, or other sensitive information retained by your browser and used with that site. These scripts can even rewrite the content of the HTML page.

Mitigation:

Configure your IPS - Intrusion Prevention System to detect and suppress this traffic.

Input Validation on the web application to normalize inputted data.

Set web apps to bind session cookies to the IP Address of the legitimate user and only permit that IP Address to use that cookie.

See the XSS (Cross Site Scripting) Prevention Cheat Sheet

See the Abridged XSS Prevention Cheat Sheet

See the DOM based XSS Prevention Cheat Sheet

See the OWASP Development Guide article on Phishing.

See the OWASP Development Guide article on Data Validation.

The following answers are incorrect:

Intrusion Detection Systems: Sorry. IDS Systems aren't usually the target of XSS attacks but a properly-configured IDS/IPS can "detect and report on malicious string and suppress the TCP connection in an attempt to mitigate the threat.

Firewalls: Sorry. Firewalls aren't usually the target of XSS attacks.

DNS Servers: Same as above, DNS Servers aren't usually targeted in XSS attacks but they play a key role in the domain name resolution in the XSS attack process.

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

CCCure Holistic Security+ CBT and Curriculum

and

https://www.owasp.org/index.php/Cross-site_Scripting_%28XSS%29

A few years ago the best choice for this question would have been seeing how far their skills can take them. Today this has changed greatly, most crimes committed are financially motivated.

Profit is the most widespread motive behind all cybercrimes and, indeed, most crimes- everyone wants to make money. Hacking for money or for free services includes a smorgasbord of crimes such as embezzlement, corporate espionage and being a “hacker for hire”. Scams are easier to undertake but the likelihood of success is much lower. Money-seekers come from any lifestyle but those with persuasive skills make better con artists in the same way as those who are exceptionally tech-savvy make better “hacks for hire”.

"White hats" are the security specialists (as opposed to Black Hats) interested in helping the community in securing their networks. They will test systems and network with the owner authorization.

A Black Hat is someone who uses his skills for offensive purpose. They do not seek authorization before they attempt to comprise the security mechanisms in place.

"Grey Hats" are people who sometimes work as a White hat and other times they will work as a "Black Hat", they have not made up their mind yet as to which side they prefer to be.

The following are incorrect answers:

All the other choices could be possible reasons but the best one today is really for financial gains.

References used for this question:

http://library.thinkquest.org/04oct/00460/crimeMotives.html

and

http://www.informit.com/articles/article.aspx?p=1160835

and

http://www.aic.gov.au/documents/1/B/A/%7B1BA0F612-613A-494D-B6C5-06938FE8BB53%7Dhtcb006.pdf

JAVA was developed so that the same program could be executed on multiple hardware and operating system platforms, it is not Architecture Specific.

The following answers are incorrect:

Object-oriented. Is not correct because JAVA is object-oriented. It should use the object-oriented programming methodology.

Distributed. Is incorrect because JAVA was developed to be able to be distrubuted, run on multiple computer systems over a network.

Multithreaded. Is incorrect because JAVA is multi-threaded that is calls to subroutines as is the case with object-oriented programming.

A virus is a program that can replicate itself on a system but not necessarily spread itself by network connections.

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.

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).

A given message and key always produce the same ciphertext.

The following answers are incorrect:

Repetitive encryption obscures any repeated patterns that may have been present in the plaintext. Is incorrect because with Electronic Code Book a given 64 bit block of plaintext always produces the same ciphertext

Individual characters are encoded by combining output from earlier encryption routines with plaintext. This is incorrect because with Electronic Code Book processing 64 bits at a time until the end of the file was reached. This is a characteristic of Cipher Feedback. Cipher Feedback the ciphertext is run through a key-generating device to create the key for the next block of plaintext.

The previous DES output is used as input. Is incorrect because This is incorrect because with Electronic Code Book processing 64 bits at a time until the end of the file was reached . This is a characteristic of Cipher Block Chaining. Cipher Block Chaining uses the output from the previous block to encrypt the next block.

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.

RSA can be used for encryption, key exchange, and digital signatures.

Key Exchange versus key Agreement

KEY EXCHANGE

Key exchange (also known as "key establishment") is any method in cryptography by which cryptographic keys are exchanged between users, allowing use of a cryptographic algorithm.

If sender and receiver wish to exchange encrypted messages, each must be equipped to encrypt messages to be sent and decrypt messages received. The nature of the equipping they require depends on the encryption technique they might use. If they use a code, both will require a copy of the same codebook. If they use a cipher, they will need appropriate keys. If the cipher is a symmetric key cipher, both will need a copy of the same key. If an asymmetric key cipher with the public/private key property, both will need the other's public key.

KEY AGREEMENT

Diffie-Hellman is a key agreement algorithm used by two parties to agree on a shared secret. The Diffie Hellman (DH) key agreement algorithm describes a means for two parties to agree upon a shared secret over a public network in such a way that the secret will be unavailable to eavesdroppers. The DH algorithm converts the shared secret into an arbitrary amount of keying material. The resulting keying material is used as a symmetric encryption key.

The other answers are not correct because:

DES and IDEA are both symmetric algorithms.

Diffie-Hellman is a common asymmetric algorithm, but is used only for key agreement. It is not typically used for data encryption and does not have digital signature capability.

References:

http://tools.ietf.org/html/rfc2631

For Diffie-Hellman information: http://www.netip.com/articles/keith/diffie-helman.htm

Source: TIPTON, et. al, Official (ISC)2 Guide to the CISSP CBK, 2007 edition, page 254.

And from the RSA web site, http://www.rsa.com/rsalabs/node.asp?id=2214 :

The RSA cryptosystem is a public-key cryptosystem that offers both encryption and digital signatures (authentication). Ronald Rivest, Adi Shamir, and Leonard Adleman developed the RSA system in 1977 [RSA78]; RSA stands for the first letter in each of its inventors' last names.

The RSA algorithm works as follows: take two large primes, p and q, and compute their product n = pq; n is called the modulus. Choose a number, e, less than n and relatively prime to (p-1)(q-1), which means e and (p-1)(q-1) have no common factors except 1. Find another number d such that (ed - 1) is divisible by (p-1)(q-1). The values e and d are called the public and private exponents, respectively. The public key is the pair (n, e); the private key is (n, d). The factors p and q may be destroyed or kept with the private key.

It is currently difficult to obtain the private key d from the public key (n, e). However if one could factor n into p and q, then one could obtain the private key d. Thus the security of the RSA system is based on the assumption that factoring is difficult. The discovery of an easy method of factoring would "break" RSA (see Question 3.1.3 and Question 2.3.3).

Here is how the RSA system can be used for encryption and digital signatures (in practice, the actual use is slightly different; see Questions 3.1.7 and 3.1.8):

Encryption

Suppose Alice wants to send a message m to Bob. Alice creates the ciphertext c by exponentiating: c = me mod n, where e and n are Bob's public key. She sends c to Bob. To decrypt, Bob also exponentiates: m = cd mod n; the relationship between e and d ensures that Bob correctly recovers m. Since only Bob knows d, only Bob can decrypt this message.

Digital Signature

Suppose Alice wants to send a message m to Bob in such a way that Bob is assured the message is both authentic, has not been tampered with, and from Alice. Alice creates a digital signature s by exponentiating: s = md mod n, where d and n are Alice's private key. She sends m and s to Bob. To verify the signature, Bob exponentiates and checks that the message m is recovered: m = se mod n, where e and n are Alice's public key.

Thus encryption and authentication take place without any sharing of private keys: each person uses only another's public key or their own private key. Anyone can send an encrypted message or verify a signed message, but only someone in possession of the correct private key can decrypt or sign a message.

CHAP is not used within IPSEC or IKE. CHAP is an authentication scheme used by Point to Point Protocol (PPP) servers to validate the identity of remote clients. CHAP periodically verifies the identity of the client by using a three-way handshake. This happens at the time of establishing the initial link (LCP), and may happen again at any time afterwards. The verification is based on a shared secret (such as the client user's password).

After the completion of the link establishment phase, the authenticator sends a "challenge" message to the peer.

The peer responds with a value calculated using a one-way hash function on the challenge and the secret combined.

The authenticator checks the response against its own calculation of the expected hash value. If the values match, the authenticator acknowledges the authentication; otherwise it should terminate the connection.

At random intervals the authenticator sends a new challenge to the peer and repeats steps 1 through 3.

The following were incorrect answers:

Pre Shared Keys

In cryptography, a pre-shared key or PSK is a shared secret which was previously shared between the two parties using some secure channel before it needs to be used. To build a key from shared secret, the key derivation function should be used. Such systems almost always use symmetric key cryptographic algorithms. The term PSK is used in WiFi encryption such as WEP or WPA, where both the wireless access points (AP) and all clients share the same key.

The characteristics of this secret or key are determined by the system which uses it; some system designs require that such keys be in a particular format. It can be a password like 'bret13i', a passphrase like 'Idaho hung gear id gene', or a hexadecimal string like '65E4 E556 8622 EEE1'. The secret is used by all systems involved in the cryptographic processes used to secure the traffic between the systems.

Certificat Based Authentication

The most common form of trusted authentication between parties in the wide world of Web commerce is the exchange of certificates. A certificate is a digital document that at a minimum includes a Distinguished Name (DN) and an associated public key.

The certificate is digitally signed by a trusted third party known as the Certificate Authority (CA). The CA vouches for the authenticity of the certificate holder. Each principal in the transaction presents certificate as its credentials. The recipient then validates the certificate’s signature against its cache of known and trusted CA certificates. A “personal

certificate” identifies an end user in a transaction; a “server certificate” identifies the service provider.

Generally, certificate formats follow the X.509 Version 3 standard. X.509 is part of the Open Systems Interconnect

(OSI) X.500 specification.

Public Key Authentication

Public key authentication is an alternative means of identifying yourself to a login server, instead of typing a password. It is more secure and more flexible, but more difficult to set up.

In conventional password authentication, you prove you are who you claim to be by proving that you know the correct password. The only way to prove you know the password is to tell the server what you think the password is. This means that if the server has been hacked, or spoofed an attacker can learn your password.

Public key authentication solves this problem. You generate a key pair, consisting of a public key (which everybody is allowed to know) and a private key (which you keep secret and do not give to anybody). The private key is able to generate signatures. A signature created using your private key cannot be forged by anybody who does not have a copy of that private key; but anybody who has your public key can verify that a particular signature is genuine.

So you generate a key pair on your own computer, and you copy the public key to the server. Then, when the server asks you to prove who you are, you can generate a signature using your private key. The server can verify that signature (since it has your public key) and allow you to log in. Now if the server is hacked or spoofed, the attacker does not gain your private key or password; they only gain one signature. And signatures cannot be re-used, so they have gained nothing.

There is a problem with this: if your private key is stored unprotected on your own computer, then anybody who gains access to your computer will be able to generate signatures as if they were you. So they will be able to log in to your server under your account. For this reason, your private key is usually encrypted when it is stored on your local machine, using a passphrase of your choice. In order to generate a signature, you must decrypt the key, so you have to type your passphrase.

References:

RFC 2409: The Internet Key Exchange (IKE); DORASWAMY, Naganand & HARKINS, Dan

Ipsec: The New Security Standard for the Internet, Intranets, and Virtual Private Networks, 1999, Prentice Hall PTR; SMITH, Richard E.

Internet Cryptography, 1997, Addison-Wesley Pub Co.; HARRIS, Shon, All-In-One CISSP Certification Exam Guide, 2001, McGraw-Hill/Osborne, page 467.

http://en.wikipedia.org/wiki/Pre-shared_key

http://www.home.umk.pl/~mgw/LDAP/RS.C4.JUN.97.pdf

http://the.earth.li/~sgtatham/putty/0.55/htmldoc/Chapter8.html#S8.1

Symmetric cryptography ciphers are generally fast and hard to break. So speed is one of the key advantage of Symmetric ciphers and NOT a disadvantage. Symmetric Ciphers uses simple encryption steps such as XOR, substitution, permutation, shifting columns, shifting rows, etc... Such steps does not required a large amount of processing power compare to the complex mathematical problem used within Asymmetric Ciphers.

Some of the weaknesses of Symmetric Ciphers are:

The lack of automated key distribution. Usually an Asymmetric cipher would be use to protect the symmetric key if it needs to be communicated to another entity securely over a public network. In the good old day this was done manually where it was distributed using the Floppy Net sometimes called the Sneaker Net (you run to someone's office to give them the key).

As far as the total number of keys are required to communicate securely between a large group of users, it does not scale very well. 10 users would require 45 keys for them to communicate securely with each other. If you have 1000 users then you would need almost half a million key to communicate secure. On Asymmetric ciphers there is only 2000 keys required for 1000 users. The formula to calculate the total number of keys required for a group of users who wishes to communicate securely with each others using Symmetric encryption is Total Number of Users (N) * Total Number of users minus one Divided by 2 or N (N-1)/2

Symmetric Ciphers are limited when it comes to security services, they cannot provide all of the security services provided by Asymmetric ciphers. Symmetric ciphers provides mostly confidentiality but can also provide integrity and authentication if a Message Authentication Code (MAC) is used and could also provide user authentication if Kerberos is used for example. Symmetric Ciphers cannot provide Digital Signature and Non-Repudiation.

Reference used for theis question:

WALLHOFF, John, CBK#5 Cryptography (CISSP Study Guide), April 2002 (page 2).

The following answers are incorrect.

Symmetric Key. Is incorrect because RSA is a Public Key or a Asymmetric Key cryptographic system and not a Symmetric Key or a Secret Key cryptographic system.

Secret Key. Is incorrect because RSA is a Public Key or a Asymmetric Key cryptographic system and not a Secret Key or a Symmetric Key cryptographic system.

Private Key. Is incorrect because Private Key is just one part if an Asymmetric Key cryptographic system, a Private Key used alone is also called a Symmetric Key cryptographic system.

Wireless Transport Layer Security (WTLS) is a communication protocol that allows wireless devices to send and receive encrypted information over the Internet. S-WAP is not defined. WSP (Wireless Session Protocol) and WDP (Wireless Datagram Protocol) are part of Wireless Access Protocol (WAP).

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 173).

There is no such thing as a Signature-Based MAC. Being the wrong choice in the list, it is the best answer to this question.

WHAT IS A Message Authentication Code (MAC)?

In Cryptography, a MAC (Message Authentication Code) also known as a cryptographic checksum, is a small block of data that is generated using a secret key and then appended to the message. When the message is received, the recipient can generate their own MAC using the secret key, and thereby know that the message has not changed either accidentally or intentionally in transit. Of course, this assurance is only as strong as the trust that the two parties have that no one else has access to the secret key.

A MAC is a small representation of a message and has the following characteristics:

A MAC is much smaller than the message generating it.

Given a MAC, it is impractical to compute the message that generated it.

Given a MAC and the message that generated it, it is impractical to find another message generating the same MAC.

See the graphic below from Wikipedia showing the creation of a MAC value:

Message Authentication Code MAC HMAC

In the example above, the sender of a message runs it through a MAC algorithm to produce a MAC data tag. The message and the MAC tag are then sent to the receiver. The receiver in turn runs the message portion of the transmission through the same MAC algorithm using the same key, producing a second MAC data tag. The receiver then compares the first MAC tag received in the transmission to the second generated MAC tag. If they are identical, the receiver can safely assume that the integrity of the message was not compromised, and the message was not altered or tampered with during transmission.

However, to allow the receiver to be able to detect replay attacks, the message itself must contain data that assures that this same message can only be sent once (e.g. time stamp, sequence number or use of a one-time MAC). Otherwise an attacker could — without even understanding its content — record this message and play it back at a later time, producing the same result as the original sender.

NOTE: There are many ways of producing a MAC value. Below you have a short list of some implementation.

The following were incorrect answers for this question:

They were all incorrect answers because they are all real type of MAC implementation.

In the case of DES-CBC, a MAC is generated using the DES algorithm in CBC mode, and the secret DES key is shared by the sender and the receiver. The MAC is actually just the last block of ciphertext generated by the algorithm. This block of data (64 bits) is attached to the unencrypted message and transmitted to the far end. All previous blocks of encrypted data are discarded to prevent any attack on the MAC itself. The receiver can just generate his own MAC using the secret DES key he shares to ensure message integrity and authentication. He knows that the message has not changed because the chaining function of CBC would significantly alter the last block of data if any bit had changed anywhere in the message. He knows the source of the message (authentication) because only one other person holds the secret key.

A Keyed-hash message authentication code (HMAC) is a specific construction for calculating a message authentication code (MAC) involving a cryptographic hash function in combination with a secret cryptographic key. As with any MAC, it may be used to simultaneously verify both the data integrity and the authentication of a message. Any cryptographic hash function, such as MD5, SHA-1, may be used in the calculation of an HMAC; the resulting MAC algorithm is termed HMAC-MD5 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, and on the size and quality of the key.

A message authentication code based on universal hashing, or UMAC, is a type of message authentication code (MAC) calculated choosing a hash function from a class of hash functions according to some secret (random) process and applying it to the message. The resulting digest or fingerprint is then encrypted to hide the identity of the hash function used. As with any MAC, it may be used to simultaneously verify both the data integrity and the authenticity of a message. UMAC is specified in RFC 4418, it has provable cryptographic strength and is usually a lot less computationally intensive than other MACs.

What is the MicMac (confusion) with MIC and MAC?

The term message integrity code (MIC) is frequently substituted for the term MAC, especially in communications, where the acronym MAC traditionally stands for Media Access Control when referring to Networking. However, some authors use MIC as a distinctly different term from a MAC; in their usage of the term the MIC operation does not use secret keys. This lack of security means that any MIC intended for use gauging message integrity should be encrypted or otherwise be protected against tampering. MIC algorithms are created such that a given message will always produce the same MIC assuming the same algorithm is used to generate both. Conversely, MAC algorithms are designed to produce matching MACs only if the same message, secret key and initialization vector are input to the same algorithm. MICs do not use secret keys and, when taken on their own, are therefore a much less reliable gauge of message integrity than MACs. Because MACs use secret keys, they do not necessarily need to be encrypted to provide the same level of assurance.

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 15799-15815). Auerbach Publications. Kindle Edition.

and

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

and

http://tools.ietf.org/html/rfc4418

A Birthday attack is usually applied to the probability of two different messages using the same hash function producing a common message digest.

The term "birthday" comes from the fact that in a room with 23 people, the probability of two of more people having the same birthday is greater than 50%.

Linear cryptanalysis is a general form of cryptanalysis based on finding affine approximations to the action of a cipher. Attacks have been developed for block ciphers and stream ciphers. Linear cryptanalysis is one of the two most widely used attacks on block ciphers; the other being differential cryptanalysis.

Differential Cryptanalysis is a potent cryptanalytic technique introduced by Biham and Shamir. Differential cryptanalysis is designed for the study and attack of DES-like cryptosystems. A DES-like cryptosystem is an iterated cryptosystem which relies on conventional cryptographic techniques such as substitution and diffusion.

Differential cryptanalysis is a general form of cryptanalysis applicable primarily to block ciphers, but also to stream ciphers and cryptographic hash functions. In the broadest sense, it is the study of how differences in an input can affect the resultant difference at the output. In the case of a block cipher, it refers to a set of techniques for tracing differences through the network of transformations, discovering where the cipher exhibits non-random behaviour, and exploiting such properties to recover the secret key.

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 163).

and

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

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-and-aes.aspx

and

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

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 which are either pre-shared or distributed using DNS (preferably with DNSSEC) and a Diffie–Hellman key exchange to set up a shared session secret from which cryptographic keys are derived.

Internet Key Exchange (IKE) Internet key exchange allows communicating partners to prove their identity to each other and establish a secure communication channel, and is applied as an authentication component of IPSec.

IKE uses two phases:

Phase 1: In this phase, the partners authenticate with each other, using one of the following:

Shared Secret: A key that is exchanged by humans via telephone, fax, encrypted e-mail, etc.

Public Key Encryption: Digital certificates are exchanged.

Revised mode of Public Key Encryption: To reduce the overhead of public key encryption, a nonce (a Cryptographic function that refers to a number or bit string used only once, in security engineering) is encrypted with the communicating partner’s public key, and the peer’s identity is encrypted with symmetric encryption using the nonce as the key. Next, IKE establishes a temporary security association and secure tunnel to protect the rest of the key exchange. Phase 2: The peers’ security associations are established, using the secure tunnel and temporary SA created at the end of phase 1.

The following reference(s) were 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 7032-7048). Auerbach Publications. Kindle Edition.

and

RFC 2409 at http://tools.ietf.org/html/rfc2409

and

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

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).

Triple DES encrypts a message three times. This encryption can be accomplished in several ways. The most secure form of triple DES is when the three encryptions are performed with three 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 152).