1 // Copyright 2010 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 des implements the Data Encryption Standard (DES) and the 6 // Triple Data Encryption Algorithm (TDEA) as defined 7 // in U.S. Federal Information Processing Standards Publication 46-3. 8 // 9 // DES is cryptographically broken and should not be used for secure 10 // applications. 11 package des 12 13 // Used to perform an initial permutation of a 64-bit input block. 14 var initialPermutation = [64]byte{ 15 6, 14, 22, 30, 38, 46, 54, 62, 16 4, 12, 20, 28, 36, 44, 52, 60, 17 2, 10, 18, 26, 34, 42, 50, 58, 18 0, 8, 16, 24, 32, 40, 48, 56, 19 7, 15, 23, 31, 39, 47, 55, 63, 20 5, 13, 21, 29, 37, 45, 53, 61, 21 3, 11, 19, 27, 35, 43, 51, 59, 22 1, 9, 17, 25, 33, 41, 49, 57, 23 } 24 25 // Used to perform a final permutation of a 4-bit preoutput block. This is the 26 // inverse of initialPermutation 27 var finalPermutation = [64]byte{ 28 24, 56, 16, 48, 8, 40, 0, 32, 29 25, 57, 17, 49, 9, 41, 1, 33, 30 26, 58, 18, 50, 10, 42, 2, 34, 31 27, 59, 19, 51, 11, 43, 3, 35, 32 28, 60, 20, 52, 12, 44, 4, 36, 33 29, 61, 21, 53, 13, 45, 5, 37, 34 30, 62, 22, 54, 14, 46, 6, 38, 35 31, 63, 23, 55, 15, 47, 7, 39, 36 } 37 38 // Used to expand an input block of 32 bits, producing an output block of 48 39 // bits. 40 var expansionFunction = [48]byte{ 41 0, 31, 30, 29, 28, 27, 28, 27, 42 26, 25, 24, 23, 24, 23, 22, 21, 43 20, 19, 20, 19, 18, 17, 16, 15, 44 16, 15, 14, 13, 12, 11, 12, 11, 45 10, 9, 8, 7, 8, 7, 6, 5, 46 4, 3, 4, 3, 2, 1, 0, 31, 47 } 48 49 // Yields a 32-bit output from a 32-bit input 50 var permutationFunction = [32]byte{ 51 16, 25, 12, 11, 3, 20, 4, 15, 52 31, 17, 9, 6, 27, 14, 1, 22, 53 30, 24, 8, 18, 0, 5, 29, 23, 54 13, 19, 2, 26, 10, 21, 28, 7, 55 } 56 57 // Used in the key schedule to select 56 bits 58 // from a 64-bit input. 59 var permutedChoice1 = [56]byte{ 60 7, 15, 23, 31, 39, 47, 55, 63, 61 6, 14, 22, 30, 38, 46, 54, 62, 62 5, 13, 21, 29, 37, 45, 53, 61, 63 4, 12, 20, 28, 1, 9, 17, 25, 64 33, 41, 49, 57, 2, 10, 18, 26, 65 34, 42, 50, 58, 3, 11, 19, 27, 66 35, 43, 51, 59, 36, 44, 52, 60, 67 } 68 69 // Used in the key schedule to produce each subkey by selecting 48 bits from 70 // the 56-bit input 71 var permutedChoice2 = [48]byte{ 72 42, 39, 45, 32, 55, 51, 53, 28, 73 41, 50, 35, 46, 33, 37, 44, 52, 74 30, 48, 40, 49, 29, 36, 43, 54, 75 15, 4, 25, 19, 9, 1, 26, 16, 76 5, 11, 23, 8, 12, 7, 17, 0, 77 22, 3, 10, 14, 6, 20, 27, 24, 78 } 79 80 // 8 S-boxes composed of 4 rows and 16 columns 81 // Used in the DES cipher function 82 var sBoxes = [8][4][16]uint8{ 83 // S-box 1 84 { 85 {14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7}, 86 {0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8}, 87 {4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0}, 88 {15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13}, 89 }, 90 // S-box 2 91 { 92 {15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10}, 93 {3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5}, 94 {0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15}, 95 {13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9}, 96 }, 97 // S-box 3 98 { 99 {10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8}, 100 {13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1}, 101 {13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7}, 102 {1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12}, 103 }, 104 // S-box 4 105 { 106 {7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15}, 107 {13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9}, 108 {10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4}, 109 {3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14}, 110 }, 111 // S-box 5 112 { 113 {2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9}, 114 {14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6}, 115 {4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14}, 116 {11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3}, 117 }, 118 // S-box 6 119 { 120 {12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11}, 121 {10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8}, 122 {9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6}, 123 {4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13}, 124 }, 125 // S-box 7 126 { 127 {4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1}, 128 {13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6}, 129 {1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2}, 130 {6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12}, 131 }, 132 // S-box 8 133 { 134 {13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7}, 135 {1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2}, 136 {7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8}, 137 {2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11}, 138 }, 139 } 140 141 // Size of left rotation per round in each half of the key schedule 142 var ksRotations = [16]uint8{1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1} 143
