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

Question

Quizplus · Accepted Answer

CTR mode and OFB mode are both popular and secure methods for building a PNRG using a block cipher. CTR mode is a counter-based mode that generates a keystream by encrypting a counter value and XORing it with the plaintext message. OFB mode, on the other hand, generates a keystream by encrypting an initial value and XORing it with the plaintext message. Both methods have good statistical properties and are considered secure for use in generating pseudorandom numbers. CBC and ECB modes, on the other hand, are not recommended for building a PNRG because they lack the necessary properties to ensure random output.

Two Approaches That Use a Block Cipher to Build a PNRG