Question

Which of the following is not a valid design parameter to be considered in designing stream ciphers?

(a) Keystream should be truly as random as possible

(b) Encryption sequence should have a large value

(c) Output of the PRNG (the key) should be sufficiently large

(d) All of the mentioned are valid points that should be considered while designing stream cipher blocks

The question was posed to me in an online interview.

The query is from Pseudorandom Number Generators and Stream Ciphers topic in chapter Pseudorandom Number Generation and Stream Ciphers and More Block Ciphers of Cryptograph & Network Security

Answer 1

Correct choice is (d) All of the mentioned are valid points that should be considered while designing stream cipher blocks

Explanation: a, b and c are all valid design parameters.