Hashes

Question 1

if the length of a hash is 128 bits, then how many messages does an attack need to search in order to find two that share the same hash?

Answer 1

2^64 (the square root of 2 to the 128th)P2 L8

Question 2

The one-way has function is important not only in message authentication, but also in digital signatures

Answer 2

false(in digital signatures, the input plain-text is sent anyway)P2 L8

Question 3

SHA processes the input one block at a time, but each block goes through the same processing

Answer 3

trueP2 L8

Question 4

HMAC is secure provided that the embedded hash function has good cryptographic strengths such as one-way and collision-resistance

Answer 4

trueP2 L8