sha256block.mx raw

   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