IAS CH3 QUIZ

The vast majority of network based symmetric cryptographic applications make use of stream ciphers.

• TRUE

• FALSE

DES uses a 56-bit block and a 64-bit key.

• TRUE

• FALSE

If the bit-stream generator is a key-controlled algorithm the two

users only need to share the generating key and then each can

produce the keystream.

• TRUE

• FALSE

A problem with the ideal block cipher using a small block size is

that it is vulnerable to a statistical analysis of the plaintext.

• TRUE

• FALSE

Confusion seeks to make the statistical relationship between the

plaintext and ciphertext as complex as possible in order to thwart

attempts to deduce the key.

• TRUE

• FALSE

All other things being equal, smaller block sizes mean greater

security.

• TRUE

• FALSE

Greater complexity in the subkey generation algorithm should lead

to greater difficulty of cryptanalysis.

• TRUE

• FALSE

Fast software encryption/decryption and ease of analysis are two

considerations in the design of a Feistel cipher.

• TRUE

• FALSE

A sequence of plaintext elements is replaced by a __________ of that sequence

which means that no elements are added, deleted or replaced in the

sequence, but rather the order in which the elements appear in the sequence

is changed.

• permutation

• stream

• diffusion

• substitution

A __________ cipher is one that encrypts a digital data stream one bit or one

byte at a time.

• stream

• product

• key

• block