Question

Multi-rate padding is denoted by

(a) 10*

(b) 10*1

(c) 10*1*

(d) 0*1

I have been asked this question during an online exam.

This interesting question is from Secure Hash Algorithms (SHA) in section Other Public Key Cryptosystems and Cryptographic Hash Functions of Cryptograph & Network Security

Answer 1

The correct answer is (b) 10*1

Easy explanation: Multi-rate padding appends a single bit 1 followed by the minimum number of 0s followed by a single bit 1 such that the length of the result is a multiple of the block length.