Source file src/crypto/sha256/sha256block.go

     1	// Copyright 2009 The Go Authors. All rights reserved.
     2	// Use of this source code is governed by a BSD-style
     3	// license that can be found in the LICENSE file.
     4	
     5	// SHA256 block step.
     6	// In its own file so that a faster assembly or C version
     7	// can be substituted easily.
     8	
     9	package sha256
    10	
    11	import "math/bits"
    12	
    13	var _K = []uint32{
    14		0x428a2f98,
    15		0x71374491,
    16		0xb5c0fbcf,
    17		0xe9b5dba5,
    18		0x3956c25b,
    19		0x59f111f1,
    20		0x923f82a4,
    21		0xab1c5ed5,
    22		0xd807aa98,
    23		0x12835b01,
    24		0x243185be,
    25		0x550c7dc3,
    26		0x72be5d74,
    27		0x80deb1fe,
    28		0x9bdc06a7,
    29		0xc19bf174,
    30		0xe49b69c1,
    31		0xefbe4786,
    32		0x0fc19dc6,
    33		0x240ca1cc,
    34		0x2de92c6f,
    35		0x4a7484aa,
    36		0x5cb0a9dc,
    37		0x76f988da,
    38		0x983e5152,
    39		0xa831c66d,
    40		0xb00327c8,
    41		0xbf597fc7,
    42		0xc6e00bf3,
    43		0xd5a79147,
    44		0x06ca6351,
    45		0x14292967,
    46		0x27b70a85,
    47		0x2e1b2138,
    48		0x4d2c6dfc,
    49		0x53380d13,
    50		0x650a7354,
    51		0x766a0abb,
    52		0x81c2c92e,
    53		0x92722c85,
    54		0xa2bfe8a1,
    55		0xa81a664b,
    56		0xc24b8b70,
    57		0xc76c51a3,
    58		0xd192e819,
    59		0xd6990624,
    60		0xf40e3585,
    61		0x106aa070,
    62		0x19a4c116,
    63		0x1e376c08,
    64		0x2748774c,
    65		0x34b0bcb5,
    66		0x391c0cb3,
    67		0x4ed8aa4a,
    68		0x5b9cca4f,
    69		0x682e6ff3,
    70		0x748f82ee,
    71		0x78a5636f,
    72		0x84c87814,
    73		0x8cc70208,
    74		0x90befffa,
    75		0xa4506ceb,
    76		0xbef9a3f7,
    77		0xc67178f2,
    78	}
    79	
    80	func blockGeneric(dig *digest, p []byte) {
    81		var w [64]uint32
    82		h0, h1, h2, h3, h4, h5, h6, h7 := dig.h[0], dig.h[1], dig.h[2], dig.h[3], dig.h[4], dig.h[5], dig.h[6], dig.h[7]
    83		for len(p) >= chunk {
    84			// Can interlace the computation of w with the
    85			// rounds below if needed for speed.
    86			for i := 0; i < 16; i++ {
    87				j := i * 4
    88				w[i] = uint32(p[j])<<24 | uint32(p[j+1])<<16 | uint32(p[j+2])<<8 | uint32(p[j+3])
    89			}
    90			for i := 16; i < 64; i++ {
    91				v1 := w[i-2]
    92				t1 := (bits.RotateLeft32(v1, -17)) ^ (bits.RotateLeft32(v1, -19)) ^ (v1 >> 10)
    93				v2 := w[i-15]
    94				t2 := (bits.RotateLeft32(v2, -7)) ^ (bits.RotateLeft32(v2, -18)) ^ (v2 >> 3)
    95				w[i] = t1 + w[i-7] + t2 + w[i-16]
    96			}
    97	
    98			a, b, c, d, e, f, g, h := h0, h1, h2, h3, h4, h5, h6, h7
    99	
   100			for i := 0; i < 64; i++ {
   101				t1 := h + ((bits.RotateLeft32(e, -6)) ^ (bits.RotateLeft32(e, -11)) ^ (bits.RotateLeft32(e, -25))) + ((e & f) ^ (^e & g)) + _K[i] + w[i]
   102	
   103				t2 := ((bits.RotateLeft32(a, -2)) ^ (bits.RotateLeft32(a, -13)) ^ (bits.RotateLeft32(a, -22))) + ((a & b) ^ (a & c) ^ (b & c))
   104	
   105				h = g
   106				g = f
   107				f = e
   108				e = d + t1
   109				d = c
   110				c = b
   111				b = a
   112				a = t1 + t2
   113			}
   114	
   115			h0 += a
   116			h1 += b
   117			h2 += c
   118			h3 += d
   119			h4 += e
   120			h5 += f
   121			h6 += g
   122			h7 += h
   123	
   124			p = p[chunk:]
   125		}
   126	
   127		dig.h[0], dig.h[1], dig.h[2], dig.h[3], dig.h[4], dig.h[5], dig.h[6], dig.h[7] = h0, h1, h2, h3, h4, h5, h6, h7
   128	}
   129	

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