SHA-512 is a variant of SHA-256 which operates on eight 64-bit buffers. The message to be hashed is rst (1) padded with its length in such away that the result is a multiple of 1024 bits long, and then (2) parsed into 1024- xed initial hash value H(O) , sequentially compute H(i) = H(il) + CM(i) (HG1)); where C is the SHA-512 compression function and + means word-wise mod 512 addition. H(N) is the hash of M All of these operators act on 64-bit words. The initial hash value H(0) is the following sequence of 64-bit words (which are obtained by taking the fractional parts of the square roots of the first eight primes): H(O) 1 = 6a09e667f3bcc908 H(0) 2 =bb67ae8584caa73b H(0) 3 =3c6ef372fe94f82b H(O) 4 =3c6ef372fe94f82b HO) 5 = 510e527fade682d1 H(O) 6 = 9b05688c2b3eb6c If H(O) 7 =1f83d9abfb41bd6b H(0) 8 =Sbe0cd19137e2179. But for SHA-640 we take two more 64-bit words.The next two words are obtained by taking the fractional parts of square roots of the ninth and tenth primes H(0)9=cbbb9d5dc1059ed8 H(0)10=629a292a367cd507
