Ch 8 - Random Number Generator
The Blum, Blum, Shub generator is referred to as a ____________ .
CSPRBG
Two approaches that use a block cipher to build a PNRG and have gained widespread acceptance are:
CTR mode and OFB mode
The __________ is drawn from the physical environment of the computer and could include things such as keystroke timing patterns, disk electrical activity, mouse movements, and instantaneous values of the system clock.
ENTROPY SOURCE
__________ is an open source project for creating truly random numbers using inexpensive cameras, open source code, and inexpensive hardware.
Entropy
A cryptographically secure pseudorandom bit generator is defined as one that passes the least significant bit test.
F
Examples of a pseudorandom function are decryption keys and nonces.
F
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.
F
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.
F
In a stream cipher structure a key is input to a pseudorandom bit generator that produces a stream of 8-bit numbers that are apparently random. The output of the generator, called a ___________ , is combined one byte at a time with the plaintext stream using the bitwise exclusive-OR operation.
KEYSTREAM
Operating systems typically provide a built-in mechanism for generating random numbers. For example, __________ uses mouse and keyboard activity, disk I/O operations, and specific interrupts.
LINUX
A __________ is used to produce a pseudorandom string of bits of some fixed length.
PRF
A fundamental requirement of the RSA public-key encryption scheme is the ability to generate _________ numbers.
PRIME
An algorithm that is used to produce an open-ended sequence of bits is referred to as a ___________ .
PRNG
__________ algorithms are designed specifically and solely for the purpose of generating pseudorandom bit streams.
PURPOSE-BUILT
The most important and widely used stream cipher is __________ .
RC4
__________ is a stream cipher designed in 1987 by Ron Rivest for RSA Security.
RC4
The purpose of the __________ test is to determine whether the number of runs of ones and zeros of various lengths is as expected for a random sequence.
RUNS
A secret key for symmetric encryption that is generated for use for a short period of time is called a _________ .
SESSION KEY
A widely used technique for pseudorandom number generation is an algorithm known as the linear congruential method.
T
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.
T
Random numbers play an important role in the use of encryption for various network security applications.
T
The longer the keyword the more difficult the cryptanalysis.
T
The principle requirement of random or pseudorandom number generation is that the generated number stream be unpredictable.
T
The security of Blum, Blum, Shub is based on the difficulty of factoring n.
T
The seed that serves as input to the PRNG must be secure for cryptographic applications.
T
The true random number generator may simply involve conversion of an analog source to a binary output.
T
There are well-defined tests for determining uniform distribution and independence to validate that a sequence of numbers is random.
T
Three broad categories of cryptographic algorithms are commonly used to create PRNGs: symmetric block ciphers, asymmetric ciphers, and hash functions and message authentication codes.
T
With true random sequences each number is statistically independent of other numbers in the sequence and therefore unpredictable.
T
A __________ takes as input a source that is effectively random.
TRNG
A __________ uses a nondeterministic source to produce randomness.
TRNG
A stream of pseudorandom numbers should exhibit two forms of unpredictability: forward and __________ .
backward
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 __________ .
consistency
Various methods of modifying a bit stream to reduce or eliminate a bias have been developed. These are referred to as ___________ algorithms.
deskewing
A source that is effectively random is referred to as a(n) __________ .
entropy source
The Linux operating system uses _________ entropy sources for generating random numbers.
four
The __________ test is the most basic test of randomness and must be included in any test suite.
frequency
Two criteria used to validate that a sequence of numbers is random are uniform distribution and __________ .
independence
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.
nonces
If the algorithm is good the resulting sequences will pass many reasonable tests of randomness. These numbers are referred to as ___________ numbers.
pseudorandom
Typically the __________ takes as input a seed plus some context specific values such as a user ID or an application ID.
pseudorandom function (PRF)
Two distinct requirements for a sequence of random numbers are unpredictability and __________ .
randomness
A pseudorandom number generator takes as input a fixed value called the __________ and produces a sequence of output bits using a deterministic algorithm.
seed
A __________ is a symmetric encryption algorithm in which ciphertext output is produced bit-by-bit or byte-by-byte from a stream of plaintext input.
stream Cipher
The distribution of bits in a random number sequence should be ___________ , therefore the frequency of occurrence of ones and zeros should be approximately equal.
uniform