1 /* 2 * Public Domain poly1305 from Andrew Moon 3 * poly1305-donna-unrolled.c from https://github.com/floodyberry/poly1305-donna 4 */ 5 6 /* $OpenBSD: poly1305.c,v 1.3 2013/12/19 22:57:13 djm Exp $ */ 7 8 #include <sys/types.h> 9 #include <stdint.h> 10 11 #include "poly1305.h" 12 13 #define mul32x32_64(a,b) ((uint64_t)(a) * (b)) 14 15 #define U8TO32_LE(p) \ 16 (((uint32_t)((p)[0])) | \ 17 ((uint32_t)((p)[1]) << 8) | \ 18 ((uint32_t)((p)[2]) << 16) | \ 19 ((uint32_t)((p)[3]) << 24)) 20 21 #define U32TO8_LE(p, v) \ 22 do { \ 23 (p)[0] = (uint8_t)((v)); \ 24 (p)[1] = (uint8_t)((v) >> 8); \ 25 (p)[2] = (uint8_t)((v) >> 16); \ 26 (p)[3] = (uint8_t)((v) >> 24); \ 27 } while (0) 28 29 void 30 poly1305_auth(unsigned char out[POLY1305_TAGLEN], const unsigned char *m, size_t inlen, const unsigned char key[POLY1305_KEYLEN]) { 31 uint32_t t0,t1,t2,t3; 32 uint32_t h0,h1,h2,h3,h4; 33 uint32_t r0,r1,r2,r3,r4; 34 uint32_t s1,s2,s3,s4; 35 uint32_t b, nb; 36 size_t j; 37 uint64_t t[5]; 38 uint64_t f0,f1,f2,f3; 39 uint32_t g0,g1,g2,g3,g4; 40 uint64_t c; 41 unsigned char mp[16]; 42 43 /* clamp key */ 44 t0 = U8TO32_LE(key+0); 45 t1 = U8TO32_LE(key+4); 46 t2 = U8TO32_LE(key+8); 47 t3 = U8TO32_LE(key+12); 48 49 /* precompute multipliers */ 50 r0 = t0 & 0x3ffffff; t0 >>= 26; t0 |= t1 << 6; 51 r1 = t0 & 0x3ffff03; t1 >>= 20; t1 |= t2 << 12; 52 r2 = t1 & 0x3ffc0ff; t2 >>= 14; t2 |= t3 << 18; 53 r3 = t2 & 0x3f03fff; t3 >>= 8; 54 r4 = t3 & 0x00fffff; 55 56 s1 = r1 * 5; 57 s2 = r2 * 5; 58 s3 = r3 * 5; 59 s4 = r4 * 5; 60 61 /* init state */ 62 h0 = 0; 63 h1 = 0; 64 h2 = 0; 65 h3 = 0; 66 h4 = 0; 67 68 /* full blocks */ 69 if (inlen < 16) goto poly1305_donna_atmost15bytes; 70 poly1305_donna_16bytes: 71 m += 16; 72 inlen -= 16; 73 74 t0 = U8TO32_LE(m-16); 75 t1 = U8TO32_LE(m-12); 76 t2 = U8TO32_LE(m-8); 77 t3 = U8TO32_LE(m-4); 78 79 h0 += t0 & 0x3ffffff; 80 h1 += ((((uint64_t)t1 << 32) | t0) >> 26) & 0x3ffffff; 81 h2 += ((((uint64_t)t2 << 32) | t1) >> 20) & 0x3ffffff; 82 h3 += ((((uint64_t)t3 << 32) | t2) >> 14) & 0x3ffffff; 83 h4 += (t3 >> 8) | (1 << 24); 84 85 86 poly1305_donna_mul: 87 t[0] = mul32x32_64(h0,r0) + mul32x32_64(h1,s4) + mul32x32_64(h2,s3) + mul32x32_64(h3,s2) + mul32x32_64(h4,s1); 88 t[1] = mul32x32_64(h0,r1) + mul32x32_64(h1,r0) + mul32x32_64(h2,s4) + mul32x32_64(h3,s3) + mul32x32_64(h4,s2); 89 t[2] = mul32x32_64(h0,r2) + mul32x32_64(h1,r1) + mul32x32_64(h2,r0) + mul32x32_64(h3,s4) + mul32x32_64(h4,s3); 90 t[3] = mul32x32_64(h0,r3) + mul32x32_64(h1,r2) + mul32x32_64(h2,r1) + mul32x32_64(h3,r0) + mul32x32_64(h4,s4); 91 t[4] = mul32x32_64(h0,r4) + mul32x32_64(h1,r3) + mul32x32_64(h2,r2) + mul32x32_64(h3,r1) + mul32x32_64(h4,r0); 92 93 h0 = (uint32_t)t[0] & 0x3ffffff; c = (t[0] >> 26); 94 t[1] += c; h1 = (uint32_t)t[1] & 0x3ffffff; b = (uint32_t)(t[1] >> 26); 95 t[2] += b; h2 = (uint32_t)t[2] & 0x3ffffff; b = (uint32_t)(t[2] >> 26); 96 t[3] += b; h3 = (uint32_t)t[3] & 0x3ffffff; b = (uint32_t)(t[3] >> 26); 97 t[4] += b; h4 = (uint32_t)t[4] & 0x3ffffff; b = (uint32_t)(t[4] >> 26); 98 h0 += b * 5; 99 100 if (inlen >= 16) goto poly1305_donna_16bytes; 101 102 /* final bytes */ 103 poly1305_donna_atmost15bytes: 104 if (!inlen) goto poly1305_donna_finish; 105 106 for (j = 0; j < inlen; j++) mp[j] = m[j]; 107 mp[j++] = 1; 108 for (; j < 16; j++) mp[j] = 0; 109 inlen = 0; 110 111 t0 = U8TO32_LE(mp+0); 112 t1 = U8TO32_LE(mp+4); 113 t2 = U8TO32_LE(mp+8); 114 t3 = U8TO32_LE(mp+12); 115 116 h0 += t0 & 0x3ffffff; 117 h1 += ((((uint64_t)t1 << 32) | t0) >> 26) & 0x3ffffff; 118 h2 += ((((uint64_t)t2 << 32) | t1) >> 20) & 0x3ffffff; 119 h3 += ((((uint64_t)t3 << 32) | t2) >> 14) & 0x3ffffff; 120 h4 += (t3 >> 8); 121 122 goto poly1305_donna_mul; 123 124 poly1305_donna_finish: 125 b = h0 >> 26; h0 = h0 & 0x3ffffff; 126 h1 += b; b = h1 >> 26; h1 = h1 & 0x3ffffff; 127 h2 += b; b = h2 >> 26; h2 = h2 & 0x3ffffff; 128 h3 += b; b = h3 >> 26; h3 = h3 & 0x3ffffff; 129 h4 += b; b = h4 >> 26; h4 = h4 & 0x3ffffff; 130 h0 += b * 5; b = h0 >> 26; h0 = h0 & 0x3ffffff; 131 h1 += b; 132 133 g0 = h0 + 5; b = g0 >> 26; g0 &= 0x3ffffff; 134 g1 = h1 + b; b = g1 >> 26; g1 &= 0x3ffffff; 135 g2 = h2 + b; b = g2 >> 26; g2 &= 0x3ffffff; 136 g3 = h3 + b; b = g3 >> 26; g3 &= 0x3ffffff; 137 g4 = h4 + b - (1 << 26); 138 139 b = (g4 >> 31) - 1; 140 nb = ~b; 141 h0 = (h0 & nb) | (g0 & b); 142 h1 = (h1 & nb) | (g1 & b); 143 h2 = (h2 & nb) | (g2 & b); 144 h3 = (h3 & nb) | (g3 & b); 145 h4 = (h4 & nb) | (g4 & b); 146 147 f0 = ((h0 ) | (h1 << 26)) + (uint64_t)U8TO32_LE(&key[16]); 148 f1 = ((h1 >> 6) | (h2 << 20)) + (uint64_t)U8TO32_LE(&key[20]); 149 f2 = ((h2 >> 12) | (h3 << 14)) + (uint64_t)U8TO32_LE(&key[24]); 150 f3 = ((h3 >> 18) | (h4 << 8)) + (uint64_t)U8TO32_LE(&key[28]); 151 152 U32TO8_LE(&out[ 0], f0); f1 += (f0 >> 32); 153 U32TO8_LE(&out[ 4], f1); f2 += (f1 >> 32); 154 U32TO8_LE(&out[ 8], f2); f3 += (f2 >> 32); 155 U32TO8_LE(&out[12], f3); 156 } 157