[444] | 1 | /* |
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| 2 | chacha-merged.c version 20080118 |
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| 3 | D. J. Bernstein |
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| 4 | Public domain. |
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| 5 | */ |
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| 6 | |
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| 7 | /* $OpenBSD: chacha_private.h,v 1.2 2013/10/04 07:02:27 djm Exp $ */ |
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| 8 | |
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| 9 | #include <stdint.h> |
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| 10 | |
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| 11 | typedef uint8_t u8; |
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| 12 | typedef uint32_t u32; |
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| 13 | |
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| 14 | typedef struct |
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| 15 | { |
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| 16 | u32 input[16]; /* could be compressed */ |
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| 17 | } chacha_ctx; |
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| 18 | |
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| 19 | #define U8V(v) ((u8)(v)) |
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| 20 | #define U32V(v) ((u32)(v)) |
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| 21 | |
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| 22 | #define ROTL32(v, n) \ |
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| 23 | (U32V((v) << (n)) | ((v) >> (32 - (n)))) |
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| 24 | |
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| 25 | #define U8TO32_LITTLE(p) \ |
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| 26 | (((u32)((p)[0]) ) | \ |
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| 27 | ((u32)((p)[1]) << 8) | \ |
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| 28 | ((u32)((p)[2]) << 16) | \ |
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| 29 | ((u32)((p)[3]) << 24)) |
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| 30 | |
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| 31 | #define U32TO8_LITTLE(p, v) \ |
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| 32 | do { \ |
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| 33 | (p)[0] = U8V((v) ); \ |
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| 34 | (p)[1] = U8V((v) >> 8); \ |
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| 35 | (p)[2] = U8V((v) >> 16); \ |
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| 36 | (p)[3] = U8V((v) >> 24); \ |
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| 37 | } while (0) |
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| 38 | |
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| 39 | #define ROTATE(v,c) (ROTL32(v,c)) |
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| 40 | #define XOR(v,w) ((v) ^ (w)) |
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| 41 | #define PLUS(v,w) (U32V((v) + (w))) |
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| 42 | #define PLUSONE(v) (PLUS((v),1)) |
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| 43 | |
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| 44 | #define QUARTERROUND(a,b,c,d) \ |
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| 45 | a = PLUS(a,b); d = ROTATE(XOR(d,a),16); \ |
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| 46 | c = PLUS(c,d); b = ROTATE(XOR(b,c),12); \ |
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| 47 | a = PLUS(a,b); d = ROTATE(XOR(d,a), 8); \ |
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| 48 | c = PLUS(c,d); b = ROTATE(XOR(b,c), 7); |
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| 49 | |
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| 50 | static const char sigma[16] = "expand 32-byte k"; |
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| 51 | static const char tau[16] = "expand 16-byte k"; |
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| 52 | |
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| 53 | static void |
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| 54 | chacha_keysetup(chacha_ctx *x,const u8 *k,u32 kbits,u32 ivbits) |
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| 55 | { |
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| 56 | const char *constants; |
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| 57 | |
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| 58 | x->input[4] = U8TO32_LITTLE(k + 0); |
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| 59 | x->input[5] = U8TO32_LITTLE(k + 4); |
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| 60 | x->input[6] = U8TO32_LITTLE(k + 8); |
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| 61 | x->input[7] = U8TO32_LITTLE(k + 12); |
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| 62 | if (kbits == 256) { /* recommended */ |
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| 63 | k += 16; |
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| 64 | constants = sigma; |
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| 65 | } else { /* kbits == 128 */ |
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| 66 | constants = tau; |
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| 67 | } |
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| 68 | x->input[8] = U8TO32_LITTLE(k + 0); |
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| 69 | x->input[9] = U8TO32_LITTLE(k + 4); |
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| 70 | x->input[10] = U8TO32_LITTLE(k + 8); |
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| 71 | x->input[11] = U8TO32_LITTLE(k + 12); |
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| 72 | x->input[0] = U8TO32_LITTLE(constants + 0); |
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| 73 | x->input[1] = U8TO32_LITTLE(constants + 4); |
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| 74 | x->input[2] = U8TO32_LITTLE(constants + 8); |
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| 75 | x->input[3] = U8TO32_LITTLE(constants + 12); |
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| 76 | } |
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| 77 | |
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| 78 | static void |
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| 79 | chacha_ivsetup(chacha_ctx *x,const u8 *iv) |
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| 80 | { |
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| 81 | x->input[12] = 0; |
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| 82 | x->input[13] = 0; |
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| 83 | x->input[14] = U8TO32_LITTLE(iv + 0); |
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| 84 | x->input[15] = U8TO32_LITTLE(iv + 4); |
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| 85 | } |
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| 86 | |
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| 87 | static void |
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| 88 | chacha_encrypt_bytes(chacha_ctx *x,const u8 *m,u8 *c,u32 bytes) |
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| 89 | { |
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| 90 | u32 x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15; |
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| 91 | u32 j0, j1, j2, j3, j4, j5, j6, j7, j8, j9, j10, j11, j12, j13, j14, j15; |
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| 92 | u8 *ctarget = NULL; |
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| 93 | u8 tmp[64]; |
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| 94 | u_int i; |
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| 95 | |
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| 96 | if (!bytes) return; |
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| 97 | |
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| 98 | j0 = x->input[0]; |
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| 99 | j1 = x->input[1]; |
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| 100 | j2 = x->input[2]; |
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| 101 | j3 = x->input[3]; |
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| 102 | j4 = x->input[4]; |
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| 103 | j5 = x->input[5]; |
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| 104 | j6 = x->input[6]; |
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| 105 | j7 = x->input[7]; |
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| 106 | j8 = x->input[8]; |
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| 107 | j9 = x->input[9]; |
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| 108 | j10 = x->input[10]; |
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| 109 | j11 = x->input[11]; |
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| 110 | j12 = x->input[12]; |
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| 111 | j13 = x->input[13]; |
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| 112 | j14 = x->input[14]; |
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| 113 | j15 = x->input[15]; |
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| 114 | |
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| 115 | for (;;) { |
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| 116 | if (bytes < 64) { |
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| 117 | for (i = 0;i < bytes;++i) tmp[i] = m[i]; |
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| 118 | m = tmp; |
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| 119 | ctarget = c; |
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| 120 | c = tmp; |
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| 121 | } |
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| 122 | x0 = j0; |
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| 123 | x1 = j1; |
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| 124 | x2 = j2; |
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| 125 | x3 = j3; |
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| 126 | x4 = j4; |
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| 127 | x5 = j5; |
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| 128 | x6 = j6; |
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| 129 | x7 = j7; |
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| 130 | x8 = j8; |
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| 131 | x9 = j9; |
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| 132 | x10 = j10; |
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| 133 | x11 = j11; |
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| 134 | x12 = j12; |
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| 135 | x13 = j13; |
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| 136 | x14 = j14; |
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| 137 | x15 = j15; |
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| 138 | for (i = 20;i > 0;i -= 2) { |
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| 139 | QUARTERROUND( x0, x4, x8,x12) |
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| 140 | QUARTERROUND( x1, x5, x9,x13) |
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| 141 | QUARTERROUND( x2, x6,x10,x14) |
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| 142 | QUARTERROUND( x3, x7,x11,x15) |
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| 143 | QUARTERROUND( x0, x5,x10,x15) |
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| 144 | QUARTERROUND( x1, x6,x11,x12) |
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| 145 | QUARTERROUND( x2, x7, x8,x13) |
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| 146 | QUARTERROUND( x3, x4, x9,x14) |
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| 147 | } |
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| 148 | x0 = PLUS(x0,j0); |
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| 149 | x1 = PLUS(x1,j1); |
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| 150 | x2 = PLUS(x2,j2); |
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| 151 | x3 = PLUS(x3,j3); |
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| 152 | x4 = PLUS(x4,j4); |
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| 153 | x5 = PLUS(x5,j5); |
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| 154 | x6 = PLUS(x6,j6); |
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| 155 | x7 = PLUS(x7,j7); |
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| 156 | x8 = PLUS(x8,j8); |
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| 157 | x9 = PLUS(x9,j9); |
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| 158 | x10 = PLUS(x10,j10); |
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| 159 | x11 = PLUS(x11,j11); |
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| 160 | x12 = PLUS(x12,j12); |
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| 161 | x13 = PLUS(x13,j13); |
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| 162 | x14 = PLUS(x14,j14); |
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| 163 | x15 = PLUS(x15,j15); |
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| 164 | |
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| 165 | #ifndef KEYSTREAM_ONLY |
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| 166 | x0 = XOR(x0,U8TO32_LITTLE(m + 0)); |
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| 167 | x1 = XOR(x1,U8TO32_LITTLE(m + 4)); |
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| 168 | x2 = XOR(x2,U8TO32_LITTLE(m + 8)); |
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| 169 | x3 = XOR(x3,U8TO32_LITTLE(m + 12)); |
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| 170 | x4 = XOR(x4,U8TO32_LITTLE(m + 16)); |
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| 171 | x5 = XOR(x5,U8TO32_LITTLE(m + 20)); |
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| 172 | x6 = XOR(x6,U8TO32_LITTLE(m + 24)); |
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| 173 | x7 = XOR(x7,U8TO32_LITTLE(m + 28)); |
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| 174 | x8 = XOR(x8,U8TO32_LITTLE(m + 32)); |
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| 175 | x9 = XOR(x9,U8TO32_LITTLE(m + 36)); |
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| 176 | x10 = XOR(x10,U8TO32_LITTLE(m + 40)); |
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| 177 | x11 = XOR(x11,U8TO32_LITTLE(m + 44)); |
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| 178 | x12 = XOR(x12,U8TO32_LITTLE(m + 48)); |
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| 179 | x13 = XOR(x13,U8TO32_LITTLE(m + 52)); |
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| 180 | x14 = XOR(x14,U8TO32_LITTLE(m + 56)); |
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| 181 | x15 = XOR(x15,U8TO32_LITTLE(m + 60)); |
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| 182 | #endif |
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| 183 | |
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| 184 | j12 = PLUSONE(j12); |
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| 185 | if (!j12) { |
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| 186 | j13 = PLUSONE(j13); |
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| 187 | /* stopping at 2^70 bytes per nonce is user's responsibility */ |
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| 188 | } |
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| 189 | |
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| 190 | U32TO8_LITTLE(c + 0,x0); |
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| 191 | U32TO8_LITTLE(c + 4,x1); |
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| 192 | U32TO8_LITTLE(c + 8,x2); |
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| 193 | U32TO8_LITTLE(c + 12,x3); |
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| 194 | U32TO8_LITTLE(c + 16,x4); |
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| 195 | U32TO8_LITTLE(c + 20,x5); |
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| 196 | U32TO8_LITTLE(c + 24,x6); |
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| 197 | U32TO8_LITTLE(c + 28,x7); |
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| 198 | U32TO8_LITTLE(c + 32,x8); |
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| 199 | U32TO8_LITTLE(c + 36,x9); |
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| 200 | U32TO8_LITTLE(c + 40,x10); |
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| 201 | U32TO8_LITTLE(c + 44,x11); |
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| 202 | U32TO8_LITTLE(c + 48,x12); |
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| 203 | U32TO8_LITTLE(c + 52,x13); |
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| 204 | U32TO8_LITTLE(c + 56,x14); |
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| 205 | U32TO8_LITTLE(c + 60,x15); |
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| 206 | |
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| 207 | if (bytes <= 64) { |
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| 208 | if (bytes < 64) { |
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| 209 | for (i = 0;i < bytes;++i) ctarget[i] = c[i]; |
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| 210 | } |
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| 211 | x->input[12] = j12; |
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| 212 | x->input[13] = j13; |
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| 213 | return; |
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| 214 | } |
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| 215 | bytes -= 64; |
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| 216 | c += 64; |
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| 217 | #ifndef KEYSTREAM_ONLY |
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| 218 | m += 64; |
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| 219 | #endif |
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| 220 | } |
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| 221 | } |
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