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