# Cryptography and Network Security

Computing

## Quiz 8 :Random Bit Generation and Stream Ciphers

Question Type
there are well-defined tests for determining uniform distribution and independence to validate that a sequence of numbers is random.
Free
True False

False

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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.
Free
True False

True

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A widely used technique for pseudorandom number generation is an algorithm known as the linear congruential method.
Free
True False

True

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A __________ takes as input a source that is effectively random.
Multiple Choice
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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.
True False
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the principle requirement of random or pseudorandom number generation is that the generated number stream be unpredictable.
True False
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three broad categories of cryptographic algorithms are commonly used to create PRNGs: symmetric block ciphers, asymmetric ciphers, and hash functions and message authentication codes.
True False
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Random numbers play an important role in the use of encryption for various network security applications.
True False
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With true random sequences each number is statistically independent of other numbers in the sequence and therefore unpredictable.
True False
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A __________ is used to produce a pseudorandom string of bits of some fixed length.
Multiple Choice
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A pseudorandom number generator takes as input a fixed value called the __________ and produces a sequence of output bits using a deterministic algorithm.
Multiple Choice
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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.
True False
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the seed that serves as input to the PRNG must be secure for cryptographic applications.
True False
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A cryptographically secure pseudorandom bit generator is defined as one that passes the least significant bit test.
True False
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the longer the keyword the more difficult the cryptanalysis.
True False
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A source that is effectively random is referred to as __________ .
Multiple Choice
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Examples of a pseudorandom function are decryption keys and nonces.
True False
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the security of Blum, Blum, Shub is based on the difficulty of factoring n.
True False