Question

What is the number of operation required to come up with 2 messages having the same message digest in SHA-512?

(a) 2^256

(b) 2^512

(c) 2^1024

(d) 2^128

The question was asked in unit test.

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

Answer 1

The correct option is (a) 2^256

For explanation I would say: The difficulty of coming up with 2 messages having the same message digest is on the order of 2^256.