A technique used to increase the security of block ciphers. It consists of steps that combine the data with portions of the key (most commonly using a simple XOR) before the first round and after the last round of encryption.
Answer(s): A
Whitening https://en.wikipedia.org/wiki/Key_whiteningIn cryptography, key whitening is a technique intended to increase the security of an iterated block cipher. It consists of steps that combine the data with portions of the key. The most common form of key whitening is xor-encrypt-xor -- using a simple XOR before the first round and after the last round of encryption.The first block cipher to use a form of key whitening is DES-X, which simply uses two extra 64-bit keys for whitening, beyond the normal 56-bit key of DES. This is intended to increase the complexity of a brute force attack, increasing the effective size of the key without major changes in the algorithm. DES-X's inventor, Ron Rivest, named the technique whitening.Incorrect answers:Key Clustering - different encryption keys generated the same ciphertext from the same plaintext message.Key Schedule - an algorithm for the key that calculates the subkeys for each round that the encryption goes through.Key Exchange - a method in cryptography by which cryptographic keys are exchanged between two parties, allowing use of a cryptographic algorithm.
A protocol for key aggreement based on Diffie-Hellman. Created in 1995. Incorporated into the public key standard IEEE P1363.
Answer(s): C
Menezes-Qu-Vanstone https://en.wikipedia.org/wiki/MQVMQV (MenezesQuVanstone) is an authenticated protocol for key agreement based on the Diffie Hellman scheme. Like other authenticated DiffieHellman schemes, MQV provides protection against an active attacker. The protocol can be modified to work in an arbitrary finite group, and, in particular, elliptic curve groups, where it is known as elliptic curve MQV (ECMQV). MQV was initially proposed by Alfred Menezes, Minghua Qu and Scott Vanstone in 1995. It was modified with Law and Solinas in 1998.Incorrect answers:Elliptic Curve - an approach to public-key cryptography based on the algebraic structure of elliptic curves over finite fields. ECC allows smaller keys compared to non-EC cryptography (based on plain Galois fields) to provide equivalent security.Euler's totient - function counts the positive integers up to a given integer n that are relatively prime to n.Blum Blum Shub - a pseudorandom number generator proposed in 1986 by Lenore Blum, Manuel Blum and Michael Shub that is derived from Michael O. Rabin's one-way function.
What is the largest key size that AES can use?
https://en.wikipedia.org/wiki/Advanced_Encryption_Standard For AES, NIST selected three members of the Rijndael family, each with a block size of 128 bits, but three different key lengths: 128, 192 and 256 bits.
Terrance oversees the key escrow server for his company. All employees use asymmetric cryptography to encrypt all emails. How many keys are needed for asymmetric cryptography?
:https://en.wikipedia.org/wiki/Public-key_cryptographyPublic-key cryptography, or asymmetric cryptography, is a cryptographic system that uses pairs of keys: public keys, which may be disseminated widely, and private keys, which are known only to the owner. The generation of such keys depends on cryptographic algorithms based on mathematical problems to produce one-way functions. Effective security only requires keeping the private key private; the public key can be openly distributed without compromising security. In such a system, any person can encrypt a message using the receiver's public key, but that encrypted message can only be decrypted with the receiver's private key.
Which of the following is required for a hash?
Answer(s): D,E
Correct answers: Variable length input, fixed length output and Not reversible https://en.wikipedia.org/wiki/Hash_functionA hash function is any function that can be used to map data of arbitrary size to fixed-size values. The values returned by a hash function are called hash values, hash codes, digests, or simply hashes. The values are used to index a fixed-size table called a hash table. Use of a hash function to index a hash table is called hashing or scatter storage addressing.
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