Wikipedia lists pseudocode for SHA-256, including seed values. Better check if they’re right.
#!/usr/bin/perl use strict; print <<HERE; Initialize hash values: (first 32 bits of the fractional parts of the square roots of the first 8 primes 2..19): HERE my ($p, $r) = 0; while ($r < 8) { next if (!prime(++$p)); printf("h%d := 0x%s\n", $r++, bits($p, 1/2)); } print <<HERE; Initialize array of round constants: (first 32 bits of the fractional parts of the cube roots of the first 64 primes 2..311): k[0..63] := HERE my ($p, $r) = 0; while ($r < 64) { next if (!prime(++$p)); print " " if ($r++ % 8 == 0); printf("0x%s", bits($p, 1/3)); print "," if ($r < 64); print $r % 8 == 0 ? "\n" : " "; } sub prime { # http://diswww.mit.edu/bloom-picayune.mit.edu/perl/10138 return ((1 x shift) !~ /^1?$|^(11+?)\1+$/); } sub bits { my ($v, $m) = @_; return unpack("H*", pack("N", ($v ** $m - int($v ** $m)) * 2**32)); }
Results:
macbook:/Users/chrisl/ 142$ perl test.pl Initialize hash values: (first 32 bits of the fractional parts of the square roots of the first 8 primes 2..19): h0 := 0x6a09e667 h1 := 0xbb67ae85 h2 := 0x3c6ef372 h3 := 0xa54ff53a h4 := 0x510e527f h5 := 0x9b05688c h6 := 0x1f83d9ab h7 := 0x5be0cd19 Initialize array of round constants: (first 32 bits of the fractional parts of the cube roots of the first 64 primes 2..311): k[0..63] := 0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da, 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070, 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
Better safe than sorry!