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Diffstat (limited to 'src/crypto/chacha8.c')
| -rw-r--r-- | src/crypto/chacha8.c | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/src/crypto/chacha8.c b/src/crypto/chacha8.c new file mode 100644 index 000000000..df135af59 --- /dev/null +++ b/src/crypto/chacha8.c @@ -0,0 +1,170 @@ +/* +chacha-merged.c version 20080118 +D. J. Bernstein +Public domain. +*/ + +#include <memory.h> +#include <stdio.h> +#include <sys/param.h> + +#include "chacha8.h" +#include "common/int-util.h" +#include "warnings.h" + +/* + * The following macros are used to obtain exact-width results. + */ +#define U8V(v) ((uint8_t)(v) & UINT8_C(0xFF)) +#define U32V(v) ((uint32_t)(v) & UINT32_C(0xFFFFFFFF)) + +/* + * The following macros load words from an array of bytes with + * different types of endianness, and vice versa. + */ +#define U8TO32_LITTLE(p) SWAP32LE(((uint32_t*)(p))[0]) +#define U32TO8_LITTLE(p, v) (((uint32_t*)(p))[0] = SWAP32LE(v)) + +#define ROTATE(v,c) (rol32(v,c)) +#define XOR(v,w) ((v) ^ (w)) +#define PLUS(v,w) (U32V((v) + (w))) +#define PLUSONE(v) (PLUS((v),1)) + +#define QUARTERROUND(a,b,c,d) \ + a = PLUS(a,b); d = ROTATE(XOR(d,a),16); \ + c = PLUS(c,d); b = ROTATE(XOR(b,c),12); \ + a = PLUS(a,b); d = ROTATE(XOR(d,a), 8); \ + c = PLUS(c,d); b = ROTATE(XOR(b,c), 7); + +static const char sigma[] = "expand 32-byte k"; + +DISABLE_GCC_AND_CLANG_WARNING(strict-aliasing) + +void chacha8(const void* data, size_t length, const uint8_t* key, const uint8_t* iv, char* cipher) { + uint32_t x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15; + uint32_t j0, j1, j2, j3, j4, j5, j6, j7, j8, j9, j10, j11, j12, j13, j14, j15; + char* ctarget = 0; + char tmp[64]; + int i; + + if (!length) return; + + j0 = U8TO32_LITTLE(sigma + 0); + j1 = U8TO32_LITTLE(sigma + 4); + j2 = U8TO32_LITTLE(sigma + 8); + j3 = U8TO32_LITTLE(sigma + 12); + j4 = U8TO32_LITTLE(key + 0); + j5 = U8TO32_LITTLE(key + 4); + j6 = U8TO32_LITTLE(key + 8); + j7 = U8TO32_LITTLE(key + 12); + j8 = U8TO32_LITTLE(key + 16); + j9 = U8TO32_LITTLE(key + 20); + j10 = U8TO32_LITTLE(key + 24); + j11 = U8TO32_LITTLE(key + 28); + j12 = 0; + j13 = 0; + j14 = U8TO32_LITTLE(iv + 0); + j15 = U8TO32_LITTLE(iv + 4); + + for (;;) { + if (length < 64) { + memcpy(tmp, data, length); + data = tmp; + ctarget = cipher; + cipher = tmp; + } + x0 = j0; + x1 = j1; + x2 = j2; + x3 = j3; + x4 = j4; + x5 = j5; + x6 = j6; + x7 = j7; + x8 = j8; + x9 = j9; + x10 = j10; + x11 = j11; + x12 = j12; + x13 = j13; + x14 = j14; + x15 = j15; + for (i = 8;i > 0;i -= 2) { + QUARTERROUND( x0, x4, x8,x12) + QUARTERROUND( x1, x5, x9,x13) + QUARTERROUND( x2, x6,x10,x14) + QUARTERROUND( x3, x7,x11,x15) + QUARTERROUND( x0, x5,x10,x15) + QUARTERROUND( x1, x6,x11,x12) + QUARTERROUND( x2, x7, x8,x13) + QUARTERROUND( x3, x4, x9,x14) + } + x0 = PLUS( x0, j0); + x1 = PLUS( x1, j1); + x2 = PLUS( x2, j2); + x3 = PLUS( x3, j3); + x4 = PLUS( x4, j4); + x5 = PLUS( x5, j5); + x6 = PLUS( x6, j6); + x7 = PLUS( x7, j7); + x8 = PLUS( x8, j8); + x9 = PLUS( x9, j9); + x10 = PLUS(x10,j10); + x11 = PLUS(x11,j11); + x12 = PLUS(x12,j12); + x13 = PLUS(x13,j13); + x14 = PLUS(x14,j14); + x15 = PLUS(x15,j15); + + x0 = XOR( x0,U8TO32_LITTLE((uint8_t*)data + 0)); + x1 = XOR( x1,U8TO32_LITTLE((uint8_t*)data + 4)); + x2 = XOR( x2,U8TO32_LITTLE((uint8_t*)data + 8)); + x3 = XOR( x3,U8TO32_LITTLE((uint8_t*)data + 12)); + x4 = XOR( x4,U8TO32_LITTLE((uint8_t*)data + 16)); + x5 = XOR( x5,U8TO32_LITTLE((uint8_t*)data + 20)); + x6 = XOR( x6,U8TO32_LITTLE((uint8_t*)data + 24)); + x7 = XOR( x7,U8TO32_LITTLE((uint8_t*)data + 28)); + x8 = XOR( x8,U8TO32_LITTLE((uint8_t*)data + 32)); + x9 = XOR( x9,U8TO32_LITTLE((uint8_t*)data + 36)); + x10 = XOR(x10,U8TO32_LITTLE((uint8_t*)data + 40)); + x11 = XOR(x11,U8TO32_LITTLE((uint8_t*)data + 44)); + x12 = XOR(x12,U8TO32_LITTLE((uint8_t*)data + 48)); + x13 = XOR(x13,U8TO32_LITTLE((uint8_t*)data + 52)); + x14 = XOR(x14,U8TO32_LITTLE((uint8_t*)data + 56)); + x15 = XOR(x15,U8TO32_LITTLE((uint8_t*)data + 60)); + + j12 = PLUSONE(j12); + if (!j12) + { + j13 = PLUSONE(j13); + /* stopping at 2^70 bytes per iv is user's responsibility */ + } + + U32TO8_LITTLE(cipher + 0,x0); + U32TO8_LITTLE(cipher + 4,x1); + U32TO8_LITTLE(cipher + 8,x2); + U32TO8_LITTLE(cipher + 12,x3); + U32TO8_LITTLE(cipher + 16,x4); + U32TO8_LITTLE(cipher + 20,x5); + U32TO8_LITTLE(cipher + 24,x6); + U32TO8_LITTLE(cipher + 28,x7); + U32TO8_LITTLE(cipher + 32,x8); + U32TO8_LITTLE(cipher + 36,x9); + U32TO8_LITTLE(cipher + 40,x10); + U32TO8_LITTLE(cipher + 44,x11); + U32TO8_LITTLE(cipher + 48,x12); + U32TO8_LITTLE(cipher + 52,x13); + U32TO8_LITTLE(cipher + 56,x14); + U32TO8_LITTLE(cipher + 60,x15); + + if (length <= 64) { + if (length < 64) { + memcpy(ctarget, cipher, length); + } + return; + } + length -= 64; + cipher += 64; + data = (uint8_t*)data + 64; + } +} |