CRY- CHAP 7

A

A __________ is used to produce a pseudorandom string of bits of some fixed length. A. PRF B. PRNG C. OFB PRNG D. TRNG

D

A __________ takes as input a source that is effectively random. A. PRF B. BBS C. PRNG D. TRNG

B

A __________ uses a nondeterministic source to produce randomness. A. CSPRBG B. TRNG C. PRNG D. BBS

B

A cryptographically secure pseudorandom bit generator is defined as one that passes the least significant bit test. A. TRUE B. FALSE

A

A pseudorandom number generator takes as input a fixed value called the __________ and produces a sequence of output bits using a deterministic algorithm. A. seed B. fixed skew C. entropy source D. keystream

C

A secret key for symmetric encryption that is generated for use for a short period of time is called a _________ . A. strategic key B. sequence key C. session key D. stream keY

B

A source that is effectively random is referred to as a(n) __________ . A. open source B. entropy source C. keystream D. seed

A

A widely used technique for pseudorandom number generation is an algorithm known as the linear congruential method. A. TRUE B. FALSE

B

Examples of a pseudorandom function are decryption keys and nonces. A. TRUE B. FALSE

A

If the PRF does not generate effectively random 128-bit output values it may be possible for an adversary to narrow the possibilities and successfully use a brute force attack A. TRUE B. FALSE

B

In key distribution and reciprocal authentication schemes two communicating parties cooperate by exchanging messages to distribute keys and/or authenticate each other. In many cases ___________ are used for handshaking to prevent replay attacks A. session keys B. nonces C. RC4's D. entropies

A

Random numbers play an important role in the use of encryption for various network security applications. A. TRUE B. FALSE

D

The Blum, Blum, Shub generator is referred to as a ____________ . A. TRNG B. OFBPRNG C. QRN D. CSPRBG

A

The __________ test is the most basic test of randomness and must be included in any test suite. A. frequency B. runs C. unpredictability D. Maurer

A

The best that can be done to determine if a PRNG generates numbers that have the characteristic of randomness is on the basis of multiple tests. These tests should seek to establish uniformity, scalability, and __________ . A. consistency B. authentication C. frequency D. sequencing

B

The distribution of bits in a random number sequence should be ___________ , therefore the frequency of occurrence of ones and zeros should be approximately equal. A. independent B. uniform C. reversed D. streamed

A

The longer the keyword the more difficult the cryptanalysis. A. TRUE B. FALSE

A

The principle requirement of random or pseudorandom number generation is that the generated number stream be unpredictable. A. TRUE B. FALSE

B

The purpose of the Maurer's universal statistical test is to determine whether the number of ones and zeros in a sequence are approximately the same as would be expected for a truly random sequence A. TRUE B. FALSE

A

The security of Blum, Blum, Shub is based on the difficulty of factoring n A. TRUE B. FALSE

A

The seed that serves as input to the PRNG must be secure for cryptographic applications A. TRUE B. FALSE

B

The stream cipher is similar to the one-time pad with a difference being that a one-time pad uses a pseudorandom number stream and a stream cipher uses a genuine random number stream. A. TRUE B. FALSE

A

The true random number generator may simply involve conversion of an analog source to a binary output. A. TRUE B. FALSE

A

There are well-defined tests for determining uniform distribution and independence to validate that a sequence of numbers is random A. TRUE B. FALSE

A

Three broad categories of cryptographic algorithms are commonly used to create PRNGs: symmetric block ciphers, asymmetric ciphers, and hash functions and message authentication codes A. TRUE B. FALSE

B

Two approaches that use a block cipher to build a PNRG and have gained widespread acceptance are: A. CTR mode and CFB mode B. CTR mode and OFB mode C. CBC mode and CFB mode D. OFB mode and ECB mode

B

Various methods of modifying a bit stream to reduce or eliminate a bias have been developed. These are referred to as ___________ algorithms. A. backward B. deskewing C. forward D. keystream

A

With true random sequences each number is statistically independent of other numbers in the sequence and therefore unpredictable A. TRUE B. FALSE

D

__________ is an open source project for creating truly random numbers using inexpensive cameras, open source code, and inexpensive hardware. A. LavaRnd B. Blum, Blum, Shub C. Maurer's statistics D. Entropy