Damien Miller | 9159310 | 2013-10-09 10:42:32 +1100 | [diff] [blame] | 1 | /* |
| 2 | chacha-merged.c version 20080118 |
| 3 | D. J. Bernstein |
| 4 | Public domain. |
| 5 | */ |
| 6 | |
| 7 | /* $OpenBSD: chacha_private.h,v 1.2 2013/10/04 07:02:27 djm Exp $ */ |
| 8 | |
| 9 | typedef unsigned char u8; |
| 10 | typedef unsigned int u32; |
| 11 | |
| 12 | typedef struct |
| 13 | { |
| 14 | u32 input[16]; /* could be compressed */ |
| 15 | } chacha_ctx; |
| 16 | |
| 17 | #define U8C(v) (v##U) |
| 18 | #define U32C(v) (v##U) |
| 19 | |
| 20 | #define U8V(v) ((u8)(v) & U8C(0xFF)) |
| 21 | #define U32V(v) ((u32)(v) & U32C(0xFFFFFFFF)) |
| 22 | |
| 23 | #define ROTL32(v, n) \ |
| 24 | (U32V((v) << (n)) | ((v) >> (32 - (n)))) |
| 25 | |
| 26 | #define U8TO32_LITTLE(p) \ |
| 27 | (((u32)((p)[0]) ) | \ |
| 28 | ((u32)((p)[1]) << 8) | \ |
| 29 | ((u32)((p)[2]) << 16) | \ |
| 30 | ((u32)((p)[3]) << 24)) |
| 31 | |
| 32 | #define U32TO8_LITTLE(p, v) \ |
| 33 | do { \ |
| 34 | (p)[0] = U8V((v) ); \ |
| 35 | (p)[1] = U8V((v) >> 8); \ |
| 36 | (p)[2] = U8V((v) >> 16); \ |
| 37 | (p)[3] = U8V((v) >> 24); \ |
| 38 | } while (0) |
| 39 | |
| 40 | #define ROTATE(v,c) (ROTL32(v,c)) |
| 41 | #define XOR(v,w) ((v) ^ (w)) |
| 42 | #define PLUS(v,w) (U32V((v) + (w))) |
| 43 | #define PLUSONE(v) (PLUS((v),1)) |
| 44 | |
| 45 | #define QUARTERROUND(a,b,c,d) \ |
| 46 | a = PLUS(a,b); d = ROTATE(XOR(d,a),16); \ |
| 47 | c = PLUS(c,d); b = ROTATE(XOR(b,c),12); \ |
| 48 | a = PLUS(a,b); d = ROTATE(XOR(d,a), 8); \ |
| 49 | c = PLUS(c,d); b = ROTATE(XOR(b,c), 7); |
| 50 | |
| 51 | static const char sigma[16] = "expand 32-byte k"; |
| 52 | static const char tau[16] = "expand 16-byte k"; |
| 53 | |
| 54 | static void |
| 55 | chacha_keysetup(chacha_ctx *x,const u8 *k,u32 kbits,u32 ivbits) |
| 56 | { |
| 57 | const char *constants; |
| 58 | |
| 59 | x->input[4] = U8TO32_LITTLE(k + 0); |
| 60 | x->input[5] = U8TO32_LITTLE(k + 4); |
| 61 | x->input[6] = U8TO32_LITTLE(k + 8); |
| 62 | x->input[7] = U8TO32_LITTLE(k + 12); |
| 63 | if (kbits == 256) { /* recommended */ |
| 64 | k += 16; |
| 65 | constants = sigma; |
| 66 | } else { /* kbits == 128 */ |
| 67 | constants = tau; |
| 68 | } |
| 69 | x->input[8] = U8TO32_LITTLE(k + 0); |
| 70 | x->input[9] = U8TO32_LITTLE(k + 4); |
| 71 | x->input[10] = U8TO32_LITTLE(k + 8); |
| 72 | x->input[11] = U8TO32_LITTLE(k + 12); |
| 73 | x->input[0] = U8TO32_LITTLE(constants + 0); |
| 74 | x->input[1] = U8TO32_LITTLE(constants + 4); |
| 75 | x->input[2] = U8TO32_LITTLE(constants + 8); |
| 76 | x->input[3] = U8TO32_LITTLE(constants + 12); |
| 77 | } |
| 78 | |
| 79 | static void |
| 80 | chacha_ivsetup(chacha_ctx *x,const u8 *iv) |
| 81 | { |
| 82 | x->input[12] = 0; |
| 83 | x->input[13] = 0; |
| 84 | x->input[14] = U8TO32_LITTLE(iv + 0); |
| 85 | x->input[15] = U8TO32_LITTLE(iv + 4); |
| 86 | } |
| 87 | |
| 88 | static void |
| 89 | chacha_encrypt_bytes(chacha_ctx *x,const u8 *m,u8 *c,u32 bytes) |
| 90 | { |
| 91 | u32 x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15; |
| 92 | u32 j0, j1, j2, j3, j4, j5, j6, j7, j8, j9, j10, j11, j12, j13, j14, j15; |
| 93 | u8 *ctarget = NULL; |
| 94 | u8 tmp[64]; |
| 95 | u_int i; |
| 96 | |
| 97 | if (!bytes) return; |
| 98 | |
| 99 | j0 = x->input[0]; |
| 100 | j1 = x->input[1]; |
| 101 | j2 = x->input[2]; |
| 102 | j3 = x->input[3]; |
| 103 | j4 = x->input[4]; |
| 104 | j5 = x->input[5]; |
| 105 | j6 = x->input[6]; |
| 106 | j7 = x->input[7]; |
| 107 | j8 = x->input[8]; |
| 108 | j9 = x->input[9]; |
| 109 | j10 = x->input[10]; |
| 110 | j11 = x->input[11]; |
| 111 | j12 = x->input[12]; |
| 112 | j13 = x->input[13]; |
| 113 | j14 = x->input[14]; |
| 114 | j15 = x->input[15]; |
| 115 | |
| 116 | for (;;) { |
| 117 | if (bytes < 64) { |
| 118 | for (i = 0;i < bytes;++i) tmp[i] = m[i]; |
| 119 | m = tmp; |
| 120 | ctarget = c; |
| 121 | c = tmp; |
| 122 | } |
| 123 | x0 = j0; |
| 124 | x1 = j1; |
| 125 | x2 = j2; |
| 126 | x3 = j3; |
| 127 | x4 = j4; |
| 128 | x5 = j5; |
| 129 | x6 = j6; |
| 130 | x7 = j7; |
| 131 | x8 = j8; |
| 132 | x9 = j9; |
| 133 | x10 = j10; |
| 134 | x11 = j11; |
| 135 | x12 = j12; |
| 136 | x13 = j13; |
| 137 | x14 = j14; |
| 138 | x15 = j15; |
| 139 | for (i = 20;i > 0;i -= 2) { |
| 140 | QUARTERROUND( x0, x4, x8,x12) |
| 141 | QUARTERROUND( x1, x5, x9,x13) |
| 142 | QUARTERROUND( x2, x6,x10,x14) |
| 143 | QUARTERROUND( x3, x7,x11,x15) |
| 144 | QUARTERROUND( x0, x5,x10,x15) |
| 145 | QUARTERROUND( x1, x6,x11,x12) |
| 146 | QUARTERROUND( x2, x7, x8,x13) |
| 147 | QUARTERROUND( x3, x4, x9,x14) |
| 148 | } |
| 149 | x0 = PLUS(x0,j0); |
| 150 | x1 = PLUS(x1,j1); |
| 151 | x2 = PLUS(x2,j2); |
| 152 | x3 = PLUS(x3,j3); |
| 153 | x4 = PLUS(x4,j4); |
| 154 | x5 = PLUS(x5,j5); |
| 155 | x6 = PLUS(x6,j6); |
| 156 | x7 = PLUS(x7,j7); |
| 157 | x8 = PLUS(x8,j8); |
| 158 | x9 = PLUS(x9,j9); |
| 159 | x10 = PLUS(x10,j10); |
| 160 | x11 = PLUS(x11,j11); |
| 161 | x12 = PLUS(x12,j12); |
| 162 | x13 = PLUS(x13,j13); |
| 163 | x14 = PLUS(x14,j14); |
| 164 | x15 = PLUS(x15,j15); |
| 165 | |
| 166 | #ifndef KEYSTREAM_ONLY |
| 167 | x0 = XOR(x0,U8TO32_LITTLE(m + 0)); |
| 168 | x1 = XOR(x1,U8TO32_LITTLE(m + 4)); |
| 169 | x2 = XOR(x2,U8TO32_LITTLE(m + 8)); |
| 170 | x3 = XOR(x3,U8TO32_LITTLE(m + 12)); |
| 171 | x4 = XOR(x4,U8TO32_LITTLE(m + 16)); |
| 172 | x5 = XOR(x5,U8TO32_LITTLE(m + 20)); |
| 173 | x6 = XOR(x6,U8TO32_LITTLE(m + 24)); |
| 174 | x7 = XOR(x7,U8TO32_LITTLE(m + 28)); |
| 175 | x8 = XOR(x8,U8TO32_LITTLE(m + 32)); |
| 176 | x9 = XOR(x9,U8TO32_LITTLE(m + 36)); |
| 177 | x10 = XOR(x10,U8TO32_LITTLE(m + 40)); |
| 178 | x11 = XOR(x11,U8TO32_LITTLE(m + 44)); |
| 179 | x12 = XOR(x12,U8TO32_LITTLE(m + 48)); |
| 180 | x13 = XOR(x13,U8TO32_LITTLE(m + 52)); |
| 181 | x14 = XOR(x14,U8TO32_LITTLE(m + 56)); |
| 182 | x15 = XOR(x15,U8TO32_LITTLE(m + 60)); |
| 183 | #endif |
| 184 | |
| 185 | j12 = PLUSONE(j12); |
| 186 | if (!j12) { |
| 187 | j13 = PLUSONE(j13); |
| 188 | /* stopping at 2^70 bytes per nonce is user's responsibility */ |
| 189 | } |
| 190 | |
| 191 | U32TO8_LITTLE(c + 0,x0); |
| 192 | U32TO8_LITTLE(c + 4,x1); |
| 193 | U32TO8_LITTLE(c + 8,x2); |
| 194 | U32TO8_LITTLE(c + 12,x3); |
| 195 | U32TO8_LITTLE(c + 16,x4); |
| 196 | U32TO8_LITTLE(c + 20,x5); |
| 197 | U32TO8_LITTLE(c + 24,x6); |
| 198 | U32TO8_LITTLE(c + 28,x7); |
| 199 | U32TO8_LITTLE(c + 32,x8); |
| 200 | U32TO8_LITTLE(c + 36,x9); |
| 201 | U32TO8_LITTLE(c + 40,x10); |
| 202 | U32TO8_LITTLE(c + 44,x11); |
| 203 | U32TO8_LITTLE(c + 48,x12); |
| 204 | U32TO8_LITTLE(c + 52,x13); |
| 205 | U32TO8_LITTLE(c + 56,x14); |
| 206 | U32TO8_LITTLE(c + 60,x15); |
| 207 | |
| 208 | if (bytes <= 64) { |
| 209 | if (bytes < 64) { |
| 210 | for (i = 0;i < bytes;++i) ctarget[i] = c[i]; |
| 211 | } |
| 212 | x->input[12] = j12; |
| 213 | x->input[13] = j13; |
| 214 | return; |
| 215 | } |
| 216 | bytes -= 64; |
| 217 | c += 64; |
| 218 | #ifndef KEYSTREAM_ONLY |
| 219 | m += 64; |
| 220 | #endif |
| 221 | } |
| 222 | } |