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Source file src/golang.org/x/crypto/salsa20/salsa/salsa208.go

Documentation: golang.org/x/crypto/salsa20/salsa

     1  // Copyright 2012 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  package salsa
     6  
     7  import "math/bits"
     8  
     9  // Core208 applies the Salsa20/8 core function to the 64-byte array in and puts
    10  // the result into the 64-byte array out. The input and output may be the same array.
    11  func Core208(out *[64]byte, in *[64]byte) {
    12  	j0 := uint32(in[0]) | uint32(in[1])<<8 | uint32(in[2])<<16 | uint32(in[3])<<24
    13  	j1 := uint32(in[4]) | uint32(in[5])<<8 | uint32(in[6])<<16 | uint32(in[7])<<24
    14  	j2 := uint32(in[8]) | uint32(in[9])<<8 | uint32(in[10])<<16 | uint32(in[11])<<24
    15  	j3 := uint32(in[12]) | uint32(in[13])<<8 | uint32(in[14])<<16 | uint32(in[15])<<24
    16  	j4 := uint32(in[16]) | uint32(in[17])<<8 | uint32(in[18])<<16 | uint32(in[19])<<24
    17  	j5 := uint32(in[20]) | uint32(in[21])<<8 | uint32(in[22])<<16 | uint32(in[23])<<24
    18  	j6 := uint32(in[24]) | uint32(in[25])<<8 | uint32(in[26])<<16 | uint32(in[27])<<24
    19  	j7 := uint32(in[28]) | uint32(in[29])<<8 | uint32(in[30])<<16 | uint32(in[31])<<24
    20  	j8 := uint32(in[32]) | uint32(in[33])<<8 | uint32(in[34])<<16 | uint32(in[35])<<24
    21  	j9 := uint32(in[36]) | uint32(in[37])<<8 | uint32(in[38])<<16 | uint32(in[39])<<24
    22  	j10 := uint32(in[40]) | uint32(in[41])<<8 | uint32(in[42])<<16 | uint32(in[43])<<24
    23  	j11 := uint32(in[44]) | uint32(in[45])<<8 | uint32(in[46])<<16 | uint32(in[47])<<24
    24  	j12 := uint32(in[48]) | uint32(in[49])<<8 | uint32(in[50])<<16 | uint32(in[51])<<24
    25  	j13 := uint32(in[52]) | uint32(in[53])<<8 | uint32(in[54])<<16 | uint32(in[55])<<24
    26  	j14 := uint32(in[56]) | uint32(in[57])<<8 | uint32(in[58])<<16 | uint32(in[59])<<24
    27  	j15 := uint32(in[60]) | uint32(in[61])<<8 | uint32(in[62])<<16 | uint32(in[63])<<24
    28  
    29  	x0, x1, x2, x3, x4, x5, x6, x7, x8 := j0, j1, j2, j3, j4, j5, j6, j7, j8
    30  	x9, x10, x11, x12, x13, x14, x15 := j9, j10, j11, j12, j13, j14, j15
    31  
    32  	for i := 0; i < 8; i += 2 {
    33  		u := x0 + x12
    34  		x4 ^= bits.RotateLeft32(u, 7)
    35  		u = x4 + x0
    36  		x8 ^= bits.RotateLeft32(u, 9)
    37  		u = x8 + x4
    38  		x12 ^= bits.RotateLeft32(u, 13)
    39  		u = x12 + x8
    40  		x0 ^= bits.RotateLeft32(u, 18)
    41  
    42  		u = x5 + x1
    43  		x9 ^= bits.RotateLeft32(u, 7)
    44  		u = x9 + x5
    45  		x13 ^= bits.RotateLeft32(u, 9)
    46  		u = x13 + x9
    47  		x1 ^= bits.RotateLeft32(u, 13)
    48  		u = x1 + x13
    49  		x5 ^= bits.RotateLeft32(u, 18)
    50  
    51  		u = x10 + x6
    52  		x14 ^= bits.RotateLeft32(u, 7)
    53  		u = x14 + x10
    54  		x2 ^= bits.RotateLeft32(u, 9)
    55  		u = x2 + x14
    56  		x6 ^= bits.RotateLeft32(u, 13)
    57  		u = x6 + x2
    58  		x10 ^= bits.RotateLeft32(u, 18)
    59  
    60  		u = x15 + x11
    61  		x3 ^= bits.RotateLeft32(u, 7)
    62  		u = x3 + x15
    63  		x7 ^= bits.RotateLeft32(u, 9)
    64  		u = x7 + x3
    65  		x11 ^= bits.RotateLeft32(u, 13)
    66  		u = x11 + x7
    67  		x15 ^= bits.RotateLeft32(u, 18)
    68  
    69  		u = x0 + x3
    70  		x1 ^= bits.RotateLeft32(u, 7)
    71  		u = x1 + x0
    72  		x2 ^= bits.RotateLeft32(u, 9)
    73  		u = x2 + x1
    74  		x3 ^= bits.RotateLeft32(u, 13)
    75  		u = x3 + x2
    76  		x0 ^= bits.RotateLeft32(u, 18)
    77  
    78  		u = x5 + x4
    79  		x6 ^= bits.RotateLeft32(u, 7)
    80  		u = x6 + x5
    81  		x7 ^= bits.RotateLeft32(u, 9)
    82  		u = x7 + x6
    83  		x4 ^= bits.RotateLeft32(u, 13)
    84  		u = x4 + x7
    85  		x5 ^= bits.RotateLeft32(u, 18)
    86  
    87  		u = x10 + x9
    88  		x11 ^= bits.RotateLeft32(u, 7)
    89  		u = x11 + x10
    90  		x8 ^= bits.RotateLeft32(u, 9)
    91  		u = x8 + x11
    92  		x9 ^= bits.RotateLeft32(u, 13)
    93  		u = x9 + x8
    94  		x10 ^= bits.RotateLeft32(u, 18)
    95  
    96  		u = x15 + x14
    97  		x12 ^= bits.RotateLeft32(u, 7)
    98  		u = x12 + x15
    99  		x13 ^= bits.RotateLeft32(u, 9)
   100  		u = x13 + x12
   101  		x14 ^= bits.RotateLeft32(u, 13)
   102  		u = x14 + x13
   103  		x15 ^= bits.RotateLeft32(u, 18)
   104  	}
   105  	x0 += j0
   106  	x1 += j1
   107  	x2 += j2
   108  	x3 += j3
   109  	x4 += j4
   110  	x5 += j5
   111  	x6 += j6
   112  	x7 += j7
   113  	x8 += j8
   114  	x9 += j9
   115  	x10 += j10
   116  	x11 += j11
   117  	x12 += j12
   118  	x13 += j13
   119  	x14 += j14
   120  	x15 += j15
   121  
   122  	out[0] = byte(x0)
   123  	out[1] = byte(x0 >> 8)
   124  	out[2] = byte(x0 >> 16)
   125  	out[3] = byte(x0 >> 24)
   126  
   127  	out[4] = byte(x1)
   128  	out[5] = byte(x1 >> 8)
   129  	out[6] = byte(x1 >> 16)
   130  	out[7] = byte(x1 >> 24)
   131  
   132  	out[8] = byte(x2)
   133  	out[9] = byte(x2 >> 8)
   134  	out[10] = byte(x2 >> 16)
   135  	out[11] = byte(x2 >> 24)
   136  
   137  	out[12] = byte(x3)
   138  	out[13] = byte(x3 >> 8)
   139  	out[14] = byte(x3 >> 16)
   140  	out[15] = byte(x3 >> 24)
   141  
   142  	out[16] = byte(x4)
   143  	out[17] = byte(x4 >> 8)
   144  	out[18] = byte(x4 >> 16)
   145  	out[19] = byte(x4 >> 24)
   146  
   147  	out[20] = byte(x5)
   148  	out[21] = byte(x5 >> 8)
   149  	out[22] = byte(x5 >> 16)
   150  	out[23] = byte(x5 >> 24)
   151  
   152  	out[24] = byte(x6)
   153  	out[25] = byte(x6 >> 8)
   154  	out[26] = byte(x6 >> 16)
   155  	out[27] = byte(x6 >> 24)
   156  
   157  	out[28] = byte(x7)
   158  	out[29] = byte(x7 >> 8)
   159  	out[30] = byte(x7 >> 16)
   160  	out[31] = byte(x7 >> 24)
   161  
   162  	out[32] = byte(x8)
   163  	out[33] = byte(x8 >> 8)
   164  	out[34] = byte(x8 >> 16)
   165  	out[35] = byte(x8 >> 24)
   166  
   167  	out[36] = byte(x9)
   168  	out[37] = byte(x9 >> 8)
   169  	out[38] = byte(x9 >> 16)
   170  	out[39] = byte(x9 >> 24)
   171  
   172  	out[40] = byte(x10)
   173  	out[41] = byte(x10 >> 8)
   174  	out[42] = byte(x10 >> 16)
   175  	out[43] = byte(x10 >> 24)
   176  
   177  	out[44] = byte(x11)
   178  	out[45] = byte(x11 >> 8)
   179  	out[46] = byte(x11 >> 16)
   180  	out[47] = byte(x11 >> 24)
   181  
   182  	out[48] = byte(x12)
   183  	out[49] = byte(x12 >> 8)
   184  	out[50] = byte(x12 >> 16)
   185  	out[51] = byte(x12 >> 24)
   186  
   187  	out[52] = byte(x13)
   188  	out[53] = byte(x13 >> 8)
   189  	out[54] = byte(x13 >> 16)
   190  	out[55] = byte(x13 >> 24)
   191  
   192  	out[56] = byte(x14)
   193  	out[57] = byte(x14 >> 8)
   194  	out[58] = byte(x14 >> 16)
   195  	out[59] = byte(x14 >> 24)
   196  
   197  	out[60] = byte(x15)
   198  	out[61] = byte(x15 >> 8)
   199  	out[62] = byte(x15 >> 16)
   200  	out[63] = byte(x15 >> 24)
   201  }
   202  

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