Mercurial > dropbear
annotate src/encauth/gcm/gcm_gf_mult.c @ 381:999a5eb4ed10 libtomcrypt-dropbear
propagate from branch 'au.asn.ucc.matt.ltc.orig' (head 52840647ac7f5c707c3bd158d119a15734a7ef28)
to branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
| author | Matt Johnston <matt@ucc.asn.au> |
|---|---|
| date | Thu, 11 Jan 2007 02:39:21 +0000 |
| parents | d5faf4814ddb |
| children |
| rev | line source |
|---|---|
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1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis |
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2 * |
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3 * LibTomCrypt is a library that provides various cryptographic |
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4 * algorithms in a highly modular and flexible manner. |
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5 * |
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6 * The library is free for all purposes without any express |
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7 * guarantee it works. |
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8 * |
| 380 | 9 * Tom St Denis, [email protected], http://libtomcrypt.com |
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10 */ |
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11 |
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12 /** |
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13 @file gcm_gf_mult.c |
| 380 | 14 GCM implementation, do the GF mult, by Tom St Denis |
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15 */ |
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16 #include "tomcrypt.h" |
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17 |
| 380 | 18 #if defined(GCM_TABLES) || defined(LRW_TABLES) || ((defined(GCM_MODE) || defined(GCM_MODE)) && defined(LTC_FAST)) |
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19 |
| 380 | 20 /* this is x*2^128 mod p(x) ... the results are 16 bytes each stored in a packed format. Since only the |
| 21 * lower 16 bits are not zero'ed I removed the upper 14 bytes */ | |
| 22 const unsigned char gcm_shift_table[256*2] = { | |
| 23 0x00, 0x00, 0x01, 0xc2, 0x03, 0x84, 0x02, 0x46, 0x07, 0x08, 0x06, 0xca, 0x04, 0x8c, 0x05, 0x4e, | |
| 24 0x0e, 0x10, 0x0f, 0xd2, 0x0d, 0x94, 0x0c, 0x56, 0x09, 0x18, 0x08, 0xda, 0x0a, 0x9c, 0x0b, 0x5e, | |
| 25 0x1c, 0x20, 0x1d, 0xe2, 0x1f, 0xa4, 0x1e, 0x66, 0x1b, 0x28, 0x1a, 0xea, 0x18, 0xac, 0x19, 0x6e, | |
| 26 0x12, 0x30, 0x13, 0xf2, 0x11, 0xb4, 0x10, 0x76, 0x15, 0x38, 0x14, 0xfa, 0x16, 0xbc, 0x17, 0x7e, | |
| 27 0x38, 0x40, 0x39, 0x82, 0x3b, 0xc4, 0x3a, 0x06, 0x3f, 0x48, 0x3e, 0x8a, 0x3c, 0xcc, 0x3d, 0x0e, | |
| 28 0x36, 0x50, 0x37, 0x92, 0x35, 0xd4, 0x34, 0x16, 0x31, 0x58, 0x30, 0x9a, 0x32, 0xdc, 0x33, 0x1e, | |
| 29 0x24, 0x60, 0x25, 0xa2, 0x27, 0xe4, 0x26, 0x26, 0x23, 0x68, 0x22, 0xaa, 0x20, 0xec, 0x21, 0x2e, | |
| 30 0x2a, 0x70, 0x2b, 0xb2, 0x29, 0xf4, 0x28, 0x36, 0x2d, 0x78, 0x2c, 0xba, 0x2e, 0xfc, 0x2f, 0x3e, | |
| 31 0x70, 0x80, 0x71, 0x42, 0x73, 0x04, 0x72, 0xc6, 0x77, 0x88, 0x76, 0x4a, 0x74, 0x0c, 0x75, 0xce, | |
| 32 0x7e, 0x90, 0x7f, 0x52, 0x7d, 0x14, 0x7c, 0xd6, 0x79, 0x98, 0x78, 0x5a, 0x7a, 0x1c, 0x7b, 0xde, | |
| 33 0x6c, 0xa0, 0x6d, 0x62, 0x6f, 0x24, 0x6e, 0xe6, 0x6b, 0xa8, 0x6a, 0x6a, 0x68, 0x2c, 0x69, 0xee, | |
| 34 0x62, 0xb0, 0x63, 0x72, 0x61, 0x34, 0x60, 0xf6, 0x65, 0xb8, 0x64, 0x7a, 0x66, 0x3c, 0x67, 0xfe, | |
| 35 0x48, 0xc0, 0x49, 0x02, 0x4b, 0x44, 0x4a, 0x86, 0x4f, 0xc8, 0x4e, 0x0a, 0x4c, 0x4c, 0x4d, 0x8e, | |
| 36 0x46, 0xd0, 0x47, 0x12, 0x45, 0x54, 0x44, 0x96, 0x41, 0xd8, 0x40, 0x1a, 0x42, 0x5c, 0x43, 0x9e, | |
| 37 0x54, 0xe0, 0x55, 0x22, 0x57, 0x64, 0x56, 0xa6, 0x53, 0xe8, 0x52, 0x2a, 0x50, 0x6c, 0x51, 0xae, | |
| 38 0x5a, 0xf0, 0x5b, 0x32, 0x59, 0x74, 0x58, 0xb6, 0x5d, 0xf8, 0x5c, 0x3a, 0x5e, 0x7c, 0x5f, 0xbe, | |
| 39 0xe1, 0x00, 0xe0, 0xc2, 0xe2, 0x84, 0xe3, 0x46, 0xe6, 0x08, 0xe7, 0xca, 0xe5, 0x8c, 0xe4, 0x4e, | |
| 40 0xef, 0x10, 0xee, 0xd2, 0xec, 0x94, 0xed, 0x56, 0xe8, 0x18, 0xe9, 0xda, 0xeb, 0x9c, 0xea, 0x5e, | |
| 41 0xfd, 0x20, 0xfc, 0xe2, 0xfe, 0xa4, 0xff, 0x66, 0xfa, 0x28, 0xfb, 0xea, 0xf9, 0xac, 0xf8, 0x6e, | |
| 42 0xf3, 0x30, 0xf2, 0xf2, 0xf0, 0xb4, 0xf1, 0x76, 0xf4, 0x38, 0xf5, 0xfa, 0xf7, 0xbc, 0xf6, 0x7e, | |
| 43 0xd9, 0x40, 0xd8, 0x82, 0xda, 0xc4, 0xdb, 0x06, 0xde, 0x48, 0xdf, 0x8a, 0xdd, 0xcc, 0xdc, 0x0e, | |
| 44 0xd7, 0x50, 0xd6, 0x92, 0xd4, 0xd4, 0xd5, 0x16, 0xd0, 0x58, 0xd1, 0x9a, 0xd3, 0xdc, 0xd2, 0x1e, | |
| 45 0xc5, 0x60, 0xc4, 0xa2, 0xc6, 0xe4, 0xc7, 0x26, 0xc2, 0x68, 0xc3, 0xaa, 0xc1, 0xec, 0xc0, 0x2e, | |
| 46 0xcb, 0x70, 0xca, 0xb2, 0xc8, 0xf4, 0xc9, 0x36, 0xcc, 0x78, 0xcd, 0xba, 0xcf, 0xfc, 0xce, 0x3e, | |
| 47 0x91, 0x80, 0x90, 0x42, 0x92, 0x04, 0x93, 0xc6, 0x96, 0x88, 0x97, 0x4a, 0x95, 0x0c, 0x94, 0xce, | |
| 48 0x9f, 0x90, 0x9e, 0x52, 0x9c, 0x14, 0x9d, 0xd6, 0x98, 0x98, 0x99, 0x5a, 0x9b, 0x1c, 0x9a, 0xde, | |
| 49 0x8d, 0xa0, 0x8c, 0x62, 0x8e, 0x24, 0x8f, 0xe6, 0x8a, 0xa8, 0x8b, 0x6a, 0x89, 0x2c, 0x88, 0xee, | |
| 50 0x83, 0xb0, 0x82, 0x72, 0x80, 0x34, 0x81, 0xf6, 0x84, 0xb8, 0x85, 0x7a, 0x87, 0x3c, 0x86, 0xfe, | |
| 51 0xa9, 0xc0, 0xa8, 0x02, 0xaa, 0x44, 0xab, 0x86, 0xae, 0xc8, 0xaf, 0x0a, 0xad, 0x4c, 0xac, 0x8e, | |
| 52 0xa7, 0xd0, 0xa6, 0x12, 0xa4, 0x54, 0xa5, 0x96, 0xa0, 0xd8, 0xa1, 0x1a, 0xa3, 0x5c, 0xa2, 0x9e, | |
| 53 0xb5, 0xe0, 0xb4, 0x22, 0xb6, 0x64, 0xb7, 0xa6, 0xb2, 0xe8, 0xb3, 0x2a, 0xb1, 0x6c, 0xb0, 0xae, | |
| 54 0xbb, 0xf0, 0xba, 0x32, 0xb8, 0x74, 0xb9, 0xb6, 0xbc, 0xf8, 0xbd, 0x3a, 0xbf, 0x7c, 0xbe, 0xbe }; | |
| 55 | |
| 56 #endif | |
| 57 | |
| 58 | |
| 59 #if defined(GCM_MODE) || defined(LRW_MODE) | |
| 60 | |
| 61 #ifndef LTC_FAST | |
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62 /* right shift */ |
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63 static void gcm_rightshift(unsigned char *a) |
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64 { |
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65 int x; |
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66 for (x = 15; x > 0; x--) { |
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67 a[x] = (a[x]>>1) | ((a[x-1]<<7)&0x80); |
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68 } |
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69 a[0] >>= 1; |
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70 } |
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71 |
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72 /* c = b*a */ |
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73 static const unsigned char mask[] = { 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01 }; |
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74 static const unsigned char poly[] = { 0x00, 0xE1 }; |
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75 |
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76 |
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77 /** |
| 380 | 78 GCM GF multiplier (internal use only) bitserial |
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79 @param a First value |
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80 @param b Second value |
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81 @param c Destination for a * b |
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82 */ |
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83 void gcm_gf_mult(const unsigned char *a, const unsigned char *b, unsigned char *c) |
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84 { |
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85 unsigned char Z[16], V[16]; |
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86 unsigned x, y, z; |
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87 |
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88 zeromem(Z, 16); |
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89 XMEMCPY(V, a, 16); |
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90 for (x = 0; x < 128; x++) { |
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91 if (b[x>>3] & mask[x&7]) { |
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92 for (y = 0; y < 16; y++) { |
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93 Z[y] ^= V[y]; |
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94 } |
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95 } |
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96 z = V[15] & 0x01; |
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97 gcm_rightshift(V); |
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98 V[0] ^= poly[z]; |
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99 } |
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100 XMEMCPY(c, Z, 16); |
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101 } |
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102 |
| 380 | 103 #else |
| 104 | |
| 105 /* map normal numbers to "ieee" way ... e.g. bit reversed */ | |
| 106 #define M(x) ( ((x&8)>>3) | ((x&4)>>1) | ((x&2)<<1) | ((x&1)<<3) ) | |
| 107 | |
| 108 #define BPD (sizeof(LTC_FAST_TYPE) * 8) | |
| 109 #define WPV (1 + (16 / sizeof(LTC_FAST_TYPE))) | |
| 110 | |
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111 /** |
| 380 | 112 GCM GF multiplier (internal use only) word oriented |
| 113 @param a First value | |
| 114 @param b Second value | |
| 115 @param c Destination for a * b | |
| 116 */ | |
| 117 void gcm_gf_mult(const unsigned char *a, const unsigned char *b, unsigned char *c) | |
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118 { |
| 380 | 119 int i, j, k, u; |
| 120 LTC_FAST_TYPE B[16][WPV], tmp[32 / sizeof(LTC_FAST_TYPE)], pB[16 / sizeof(LTC_FAST_TYPE)], zz, z; | |
| 121 unsigned char pTmp[32]; | |
| 122 | |
| 123 /* create simple tables */ | |
| 124 zeromem(B[0], sizeof(B[0])); | |
| 125 zeromem(B[M(1)], sizeof(B[M(1)])); | |
| 126 | |
| 127 #ifdef ENDIAN_32BITWORD | |
| 128 for (i = 0; i < 4; i++) { | |
| 129 LOAD32H(B[M(1)][i], a + (i<<2)); | |
| 130 LOAD32L(pB[i], b + (i<<2)); | |
| 131 } | |
| 132 #else | |
| 133 for (i = 0; i < 2; i++) { | |
| 134 LOAD64H(B[M(1)][i], a + (i<<3)); | |
| 135 LOAD64L(pB[i], b + (i<<3)); | |
| 136 } | |
| 137 #endif | |
| 138 | |
| 139 /* now create 2, 4 and 8 */ | |
| 140 B[M(2)][0] = B[M(1)][0] >> 1; | |
| 141 B[M(4)][0] = B[M(1)][0] >> 2; | |
| 142 B[M(8)][0] = B[M(1)][0] >> 3; | |
| 143 for (i = 1; i < (int)WPV; i++) { | |
| 144 B[M(2)][i] = (B[M(1)][i-1] << (BPD-1)) | (B[M(1)][i] >> 1); | |
| 145 B[M(4)][i] = (B[M(1)][i-1] << (BPD-2)) | (B[M(1)][i] >> 2); | |
| 146 B[M(8)][i] = (B[M(1)][i-1] << (BPD-3)) | (B[M(1)][i] >> 3); | |
| 147 } | |
| 148 | |
| 149 /* now all values with two bits which are 3, 5, 6, 9, 10, 12 */ | |
| 150 for (i = 0; i < (int)WPV; i++) { | |
| 151 B[M(3)][i] = B[M(1)][i] ^ B[M(2)][i]; | |
| 152 B[M(5)][i] = B[M(1)][i] ^ B[M(4)][i]; | |
| 153 B[M(6)][i] = B[M(2)][i] ^ B[M(4)][i]; | |
| 154 B[M(9)][i] = B[M(1)][i] ^ B[M(8)][i]; | |
| 155 B[M(10)][i] = B[M(2)][i] ^ B[M(8)][i]; | |
| 156 B[M(12)][i] = B[M(8)][i] ^ B[M(4)][i]; | |
| 157 | |
| 158 /* now all 3 bit values and the only 4 bit value: 7, 11, 13, 14, 15 */ | |
| 159 B[M(7)][i] = B[M(3)][i] ^ B[M(4)][i]; | |
| 160 B[M(11)][i] = B[M(3)][i] ^ B[M(8)][i]; | |
| 161 B[M(13)][i] = B[M(1)][i] ^ B[M(12)][i]; | |
| 162 B[M(14)][i] = B[M(6)][i] ^ B[M(8)][i]; | |
| 163 B[M(15)][i] = B[M(7)][i] ^ B[M(8)][i]; | |
| 164 } | |
| 165 | |
| 166 zeromem(tmp, sizeof(tmp)); | |
| 167 | |
| 168 /* compute product four bits of each word at a time */ | |
| 169 /* for each nibble */ | |
| 170 for (i = (BPD/4)-1; i >= 0; i--) { | |
| 171 /* for each word */ | |
| 172 for (j = 0; j < (int)(WPV-1); j++) { | |
| 173 /* grab the 4 bits recall the nibbles are backwards so it's a shift by (i^1)*4 */ | |
| 174 u = (pB[j] >> ((i^1)<<2)) & 15; | |
| 175 | |
| 176 /* add offset by the word count the table looked up value to the result */ | |
| 177 for (k = 0; k < (int)WPV; k++) { | |
| 178 tmp[k+j] ^= B[u][k]; | |
| 179 } | |
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180 } |
| 380 | 181 /* shift result up by 4 bits */ |
| 182 if (i != 0) { | |
| 183 for (z = j = 0; j < (int)(32 / sizeof(LTC_FAST_TYPE)); j++) { | |
| 184 zz = tmp[j] << (BPD-4); | |
| 185 tmp[j] = (tmp[j] >> 4) | z; | |
| 186 z = zz; | |
| 187 } | |
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188 } |
| 380 | 189 } |
| 190 | |
| 191 /* store product */ | |
| 192 #ifdef ENDIAN_32BITWORD | |
| 193 for (i = 0; i < 8; i++) { | |
| 194 STORE32H(tmp[i], pTmp + (i<<2)); | |
| 195 } | |
| 196 #else | |
| 197 for (i = 0; i < 4; i++) { | |
| 198 STORE64H(tmp[i], pTmp + (i<<3)); | |
| 199 } | |
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200 #endif |
| 380 | 201 |
| 202 /* reduce by taking most significant byte and adding the appropriate two byte sequence 16 bytes down */ | |
| 203 for (i = 31; i >= 16; i--) { | |
| 204 pTmp[i-16] ^= gcm_shift_table[((unsigned)pTmp[i]<<1)]; | |
| 205 pTmp[i-15] ^= gcm_shift_table[((unsigned)pTmp[i]<<1)+1]; | |
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206 } |
| 380 | 207 |
| 208 for (i = 0; i < 16; i++) { | |
| 209 c[i] = pTmp[i]; | |
| 210 } | |
| 211 | |
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212 } |
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213 |
| 380 | 214 #endif |
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215 |
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216 #endif |
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217 |
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218 /* $Source: /cvs/libtom/libtomcrypt/src/encauth/gcm/gcm_gf_mult.c,v $ */ |
| 380 | 219 /* $Revision: 1.23 $ */ |
| 220 /* $Date: 2006/03/31 14:15:35 $ */ | |
| 221 |