Re:Notes on Intel Microcode Updates
by lucb1e on Wednesday April 03, 2013 @09:21AM
(#5485824)
There is one thing that I don't understand:
> The RSA signature was located, and the signed data is a PKCS#1 1.5 encoded hash value. Older processor models use a 160-bit digest (SHA1), and newer process models use a 256-bit digest (SHA2).
Why is it assumed that any random 160-bits digest is SHA1 and any random 256-bits digest SHA-256? I don't know all Merkle-Damgard hashing algorithms by heart, but are SHA-1 and SHA-256 the only ones using 512-bits blocks and 160/256-bit digest lengths?
> The RSA signature was located, and the signed data is a PKCS#1 1.5 encoded hash value. Older processor models use a 160-bit digest (SHA1), and newer process models use a 256-bit digest (SHA2).
Why is it assumed that any random 160-bits digest is SHA1 and any random 256-bits digest SHA-256? I don't know all Merkle-Damgard hashing algorithms by heart, but are SHA-1 and SHA-256 the only ones using 512-bits blocks and 160/256-bit digest lengths?