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Source file src/crypto/sha256/sha256block.go

Documentation: crypto/sha256

  // Copyright 2009 The Go Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style
  // license that can be found in the LICENSE file.
  
  // SHA256 block step.
  // In its own file so that a faster assembly or C version
  // can be substituted easily.
  
  package sha256
  
  var _K = []uint32{
  	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,
  }
  
  func blockGeneric(dig *digest, p []byte) {
  	var w [64]uint32
  	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]
  	for len(p) >= chunk {
  		// Can interlace the computation of w with the
  		// rounds below if needed for speed.
  		for i := 0; i < 16; i++ {
  			j := i * 4
  			w[i] = uint32(p[j])<<24 | uint32(p[j+1])<<16 | uint32(p[j+2])<<8 | uint32(p[j+3])
  		}
  		for i := 16; i < 64; i++ {
  			v1 := w[i-2]
  			t1 := (v1>>17 | v1<<(32-17)) ^ (v1>>19 | v1<<(32-19)) ^ (v1 >> 10)
  			v2 := w[i-15]
  			t2 := (v2>>7 | v2<<(32-7)) ^ (v2>>18 | v2<<(32-18)) ^ (v2 >> 3)
  			w[i] = t1 + w[i-7] + t2 + w[i-16]
  		}
  
  		a, b, c, d, e, f, g, h := h0, h1, h2, h3, h4, h5, h6, h7
  
  		for i := 0; i < 64; i++ {
  			t1 := h + ((e>>6 | e<<(32-6)) ^ (e>>11 | e<<(32-11)) ^ (e>>25 | e<<(32-25))) + ((e & f) ^ (^e & g)) + _K[i] + w[i]
  
  			t2 := ((a>>2 | a<<(32-2)) ^ (a>>13 | a<<(32-13)) ^ (a>>22 | a<<(32-22))) + ((a & b) ^ (a & c) ^ (b & c))
  
  			h = g
  			g = f
  			f = e
  			e = d + t1
  			d = c
  			c = b
  			b = a
  			a = t1 + t2
  		}
  
  		h0 += a
  		h1 += b
  		h2 += c
  		h3 += d
  		h4 += e
  		h5 += f
  		h6 += g
  		h7 += h
  
  		p = p[chunk:]
  	}
  
  	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
  }
  

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