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Diffstat (limited to 'node/Salsa20.cpp')
| -rw-r--r-- | node/Salsa20.cpp | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/node/Salsa20.cpp b/node/Salsa20.cpp new file mode 100644 index 00000000..802f82e9 --- /dev/null +++ b/node/Salsa20.cpp @@ -0,0 +1,221 @@ +/* + * Based on public domain code available at: http://cr.yp.to/snuffle.html + * + * This therefore is public domain. + */ + +#include "Salsa20.hpp" + +#define ROTATE(v,c) (((v) << (c)) | ((v) >> (32 - (c)))) +#define XOR(v,w) ((v) ^ (w)) +#define PLUS(v,w) ((uint32_t)((v) + (w))) +#define PLUSONE(v) ((uint32_t)((v) + 1)) + +#if __BYTE_ORDER == __LITTLE_ENDIAN +#define U8TO32_LITTLE(p) (*((const uint32_t *)((const void *)(p)))) +#define U32TO8_LITTLE(c,v) *((uint32_t *)((void *)(c))) = (v) +#else +#ifdef __GNUC__ +#define U8TO32_LITTLE(p) __builtin_bswap32(*((const uint32_t *)((const void *)(p)))) +#define U32TO8_LITTLE(c,v) *((uint32_t *)((void *)(c))) = __builtin_bswap32((v)) +#else +error need be; +#endif +#endif + +namespace ZeroTier { + +static const char *sigma = "expand 32-byte k"; +static const char *tau = "expand 16-byte k"; + +void Salsa20::init(const void *key,unsigned int kbits,const void *iv) + throw() +{ + const char *constants; + const uint8_t *k = (const uint8_t *)key; + + _state[1] = U8TO32_LITTLE(k + 0); + _state[2] = U8TO32_LITTLE(k + 4); + _state[3] = U8TO32_LITTLE(k + 8); + _state[4] = U8TO32_LITTLE(k + 12); + if (kbits == 256) { /* recommended */ + k += 16; + constants = sigma; + } else { /* kbits == 128 */ + constants = tau; + } + _state[11] = U8TO32_LITTLE(k + 0); + _state[12] = U8TO32_LITTLE(k + 4); + _state[13] = U8TO32_LITTLE(k + 8); + _state[14] = U8TO32_LITTLE(k + 12); + + _state[6] = U8TO32_LITTLE(((const uint8_t *)iv) + 0); + _state[7] = U8TO32_LITTLE(((const uint8_t *)iv) + 4); + _state[8] = 0; + _state[9] = 0; + + _state[0] = U8TO32_LITTLE(constants + 0); + _state[5] = U8TO32_LITTLE(constants + 4); + _state[10] = U8TO32_LITTLE(constants + 8); + _state[15] = U8TO32_LITTLE(constants + 12); +} + +void Salsa20::encrypt(const void *in,void *out,unsigned int bytes) + throw() +{ + 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; + uint8_t tmp[64]; + const uint8_t *m = (const uint8_t *)in; + uint8_t *c = (uint8_t *)out; + uint8_t *ctarget = c; + unsigned int i; + + if (!bytes) return; + + j0 = _state[0]; + j1 = _state[1]; + j2 = _state[2]; + j3 = _state[3]; + j4 = _state[4]; + j5 = _state[5]; + j6 = _state[6]; + j7 = _state[7]; + j8 = _state[8]; + j9 = _state[9]; + j10 = _state[10]; + j11 = _state[11]; + j12 = _state[12]; + j13 = _state[13]; + j14 = _state[14]; + j15 = _state[15]; + + for (;;) { + if (bytes < 64) { + for (i = 0;i < bytes;++i) tmp[i] = m[i]; + m = tmp; + ctarget = c; + c = 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 = 20;i > 0;i -= 2) { + x4 = XOR( x4,ROTATE(PLUS( x0,x12), 7)); + x8 = XOR( x8,ROTATE(PLUS( x4, x0), 9)); + x12 = XOR(x12,ROTATE(PLUS( x8, x4),13)); + x0 = XOR( x0,ROTATE(PLUS(x12, x8),18)); + x9 = XOR( x9,ROTATE(PLUS( x5, x1), 7)); + x13 = XOR(x13,ROTATE(PLUS( x9, x5), 9)); + x1 = XOR( x1,ROTATE(PLUS(x13, x9),13)); + x5 = XOR( x5,ROTATE(PLUS( x1,x13),18)); + x14 = XOR(x14,ROTATE(PLUS(x10, x6), 7)); + x2 = XOR( x2,ROTATE(PLUS(x14,x10), 9)); + x6 = XOR( x6,ROTATE(PLUS( x2,x14),13)); + x10 = XOR(x10,ROTATE(PLUS( x6, x2),18)); + x3 = XOR( x3,ROTATE(PLUS(x15,x11), 7)); + x7 = XOR( x7,ROTATE(PLUS( x3,x15), 9)); + x11 = XOR(x11,ROTATE(PLUS( x7, x3),13)); + x15 = XOR(x15,ROTATE(PLUS(x11, x7),18)); + x1 = XOR( x1,ROTATE(PLUS( x0, x3), 7)); + x2 = XOR( x2,ROTATE(PLUS( x1, x0), 9)); + x3 = XOR( x3,ROTATE(PLUS( x2, x1),13)); + x0 = XOR( x0,ROTATE(PLUS( x3, x2),18)); + x6 = XOR( x6,ROTATE(PLUS( x5, x4), 7)); + x7 = XOR( x7,ROTATE(PLUS( x6, x5), 9)); + x4 = XOR( x4,ROTATE(PLUS( x7, x6),13)); + x5 = XOR( x5,ROTATE(PLUS( x4, x7),18)); + x11 = XOR(x11,ROTATE(PLUS(x10, x9), 7)); + x8 = XOR( x8,ROTATE(PLUS(x11,x10), 9)); + x9 = XOR( x9,ROTATE(PLUS( x8,x11),13)); + x10 = XOR(x10,ROTATE(PLUS( x9, x8),18)); + x12 = XOR(x12,ROTATE(PLUS(x15,x14), 7)); + x13 = XOR(x13,ROTATE(PLUS(x12,x15), 9)); + x14 = XOR(x14,ROTATE(PLUS(x13,x12),13)); + x15 = XOR(x15,ROTATE(PLUS(x14,x13),18)); + } + 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(m + 0)); + x1 = XOR(x1,U8TO32_LITTLE(m + 4)); + x2 = XOR(x2,U8TO32_LITTLE(m + 8)); + x3 = XOR(x3,U8TO32_LITTLE(m + 12)); + x4 = XOR(x4,U8TO32_LITTLE(m + 16)); + x5 = XOR(x5,U8TO32_LITTLE(m + 20)); + x6 = XOR(x6,U8TO32_LITTLE(m + 24)); + x7 = XOR(x7,U8TO32_LITTLE(m + 28)); + x8 = XOR(x8,U8TO32_LITTLE(m + 32)); + x9 = XOR(x9,U8TO32_LITTLE(m + 36)); + x10 = XOR(x10,U8TO32_LITTLE(m + 40)); + x11 = XOR(x11,U8TO32_LITTLE(m + 44)); + x12 = XOR(x12,U8TO32_LITTLE(m + 48)); + x13 = XOR(x13,U8TO32_LITTLE(m + 52)); + x14 = XOR(x14,U8TO32_LITTLE(m + 56)); + x15 = XOR(x15,U8TO32_LITTLE(m + 60)); + + j8 = PLUSONE(j8); + if (!j8) { + j9 = PLUSONE(j9); + /* stopping at 2^70 bytes per nonce is user's responsibility */ + } + + U32TO8_LITTLE(c + 0,x0); + U32TO8_LITTLE(c + 4,x1); + U32TO8_LITTLE(c + 8,x2); + U32TO8_LITTLE(c + 12,x3); + U32TO8_LITTLE(c + 16,x4); + U32TO8_LITTLE(c + 20,x5); + U32TO8_LITTLE(c + 24,x6); + U32TO8_LITTLE(c + 28,x7); + U32TO8_LITTLE(c + 32,x8); + U32TO8_LITTLE(c + 36,x9); + U32TO8_LITTLE(c + 40,x10); + U32TO8_LITTLE(c + 44,x11); + U32TO8_LITTLE(c + 48,x12); + U32TO8_LITTLE(c + 52,x13); + U32TO8_LITTLE(c + 56,x14); + U32TO8_LITTLE(c + 60,x15); + + if (bytes <= 64) { + if (bytes < 64) { + for (i = 0;i < bytes;++i) ctarget[i] = c[i]; + } + _state[8] = j8; + _state[9] = j9; + return; + } + bytes -= 64; + c += 64; + m += 64; + } +} + +} // namespace ZeroTier |