Computer Security Midterm CH4

brute-force attack

A __________ is to try every possible key on a piece of ciphertext until an intelligible translation into plaintext is obtained.

pseudorandom

A __________ stream is one that is unpredictable without knowledge of the input key and which has an apparently random character.

T

An important element in many computer security services and applications is the use of cryptographic algorithms. True or False

keystream

Combined one byte at a time with the plaintext stream using the XOR operation, a __________ is the output of the pseudorandom bit generator.

public-key

Digital signatures and key management are the two most important applications of __________ encryption.

Electronic Frontier Foundation (EFF)

July 1998 the __________ announced that it had broken a DES encryption using a special purpose "DES cracker" machine.

F

Like the MAC, a hash function also takes a secret key as input. True or False

F

Public-key algorithms are based on simple operations on bit patterns. True or False

T

Public-key cryptography is asymmetric. True or False

T

Some form of protocol is needed for public-key distribution. True or False

public and private key

The __________ is a pair of keys that have been selected so that if one is used for encryption, the other is used for decryption.

F

The purpose of the DSS algorithm is to enable two users to securely reach agreement about a shared secret that can be used as a secret key for subsequent symmetric encryption of messages. True or False

Diffie-Hellman Key Agreement

The purpose of the __________ algorithm is to enable two users to securely reach agreement about a shared secret that can be used as a secret key for subsequent symmetric encryption of messages.

electronic codebook (ECB)

The simplest approach to multiple block encryption is known as __________ mode, in which plaintext is handled b bits at a time and each block of plaintext is encrypted using the same key.

T

The strength of a hash function against brute-force attacks depends solely on the length of the hash code produced by the algorithm. True or False

data at rest

Transmitted data stored locally are referred to as __________ .

RSA

__________ is a block cipher in which the plaintext and ciphertext are integers between 0 and n-1 for some n.

library-based tape encryption

__________ is provided by means of a co-processor board embedded in the tape drive and tape library hardware.

back-end appliance

A _________ is a hardware device that sits between servers and storage systems and encrypts all data going from the server to the storage system and decrypts data going in the opposite direction.

strong hash function

A _________ protects against an attack in which one party generates a message for another party to sign.

digital signature

A __________ is created by using a secure hash function to generate a hash value for a message and then encrypting the hash code with a private key.