Schneier On the US Crypto Competition

Bruce Schneier has a commentary in Wired titled An American Idol for Crypto Geeks on the US government's competition for a new cryptographic hash function to become the national standard, covered here recently. He talks about how much the competition, slated to wrap up by 2011, will advance the cryptographic state of the art. And how much fun he expects to have.

SHA-256?

[Bromskloss]

What about SHA-512?

Re:SHA-256?

[Phleg]

It uses a word size of 64 bits, so is not as fast on 32-bit computers. Also, I believe it's received less scrutiny than SHA-256. IANAC.

Theyre sking to find unSHA func or bigger word bit

[rogtioko]

NIST is either looking for an entirely revolutionary function to the SHA series, considering the emphasis that SHA-1 has been around since 1995, or seeking a function that supplies words greater than 64bits and also but albeit distantly 256bit and higher to counter higher chunk rate processors. If they're looking for something different than SHA, here are factors they are considering: the fact that all the SHA hashes after SHA-1 use part, maybe all, of SHA-1's 4 functions and vary only by the function's output word bit size, which SHA-256 and SHA-384-512 change with summation functions into the mix. For example, here is SHA-1's functions

f subscript t (x,y,z) =

Ch(x,y,z)=(x^y) xor (complement x^z) 0 less than or = t less than or = 19

Parity (x,y,z)=x xor y xor z 20 less than or = t less than or = 39

Maj (x,y,z)=(x^y) xor (x^z) xor (y^z) 40 less than or = t less than or = 59

Parity (x,y,z)=x xor y xor z 60 less than or = t less than or = 79

(4.1)

and SHA-384 and SHA-512 functions

Ch( x,y,z) = ( x^y) xor (complement x^z) (4.8)

Maj(x,y,z) = (x^y) xor (x^z) xor (y^z) (4.9)

(big sigma subscript 0) (superscript {512}) (x) = ROTR (superscript 28) (x) xor ROTR (superscript 34) (x) xor ROTR (superscript 39)(x) (4.10)

(big sigma subscript 1) (superscript {512}) (x) = ROTR (superscript 14) (x) xor ROTR (superscript 18) (x) xor ROTR (superscript 41) (x) (4.11)

(small sigma subscript 0) (superscript {512}) x = ROTR (superscript 1) (x) xor ROTR (superscript 8)(x) xor SHR (superscript 7) (x) (4.12)

(small sigma subscript 1) (superscript {512}) x = ROTR (superscript 19) (x) xor ROTR (superscript 61) (x) xor SHR (superscript 6) (x) (4.13)