Line data    Source code

       1             : // Copyright (c) 2019 The Bitcoin Core developers
       2             : // Distributed under the MIT software license, see the accompanying
       3             : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
       4             : 
       5             : #include <crypto/common.h>
       6             : #include <crypto/poly1305.h>
       7             : 
       8             : #include <string.h>
       9             : 
      10             : namespace poly1305_donna {
      11             : 
      12             : // Based on the public domain implementation by Andrew Moon
      13             : // poly1305-donna-32.h from https://github.com/floodyberry/poly1305-donna
      14             : 
      15     1404174 : void poly1305_init(poly1305_context *st, const unsigned char key[32]) noexcept {
      16             :     /* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
      17     1404174 :     st->r[0] = (ReadLE32(&key[ 0])     ) & 0x3ffffff;
      18     1404174 :     st->r[1] = (ReadLE32(&key[ 3]) >> 2) & 0x3ffff03;
      19     1404174 :     st->r[2] = (ReadLE32(&key[ 6]) >> 4) & 0x3ffc0ff;
      20     1404174 :     st->r[3] = (ReadLE32(&key[ 9]) >> 6) & 0x3f03fff;
      21     1404174 :     st->r[4] = (ReadLE32(&key[12]) >> 8) & 0x00fffff;
      22             : 
      23             :     /* h = 0 */
      24     1404174 :     st->h[0] = 0;
      25     1404174 :     st->h[1] = 0;
      26     1404174 :     st->h[2] = 0;
      27     1404174 :     st->h[3] = 0;
      28     1404174 :     st->h[4] = 0;
      29             : 
      30             :     /* save pad for later */
      31     1404174 :     st->pad[0] = ReadLE32(&key[16]);
      32     1404174 :     st->pad[1] = ReadLE32(&key[20]);
      33     1404174 :     st->pad[2] = ReadLE32(&key[24]);
      34     1404174 :     st->pad[3] = ReadLE32(&key[28]);
      35             : 
      36     1404174 :     st->leftover = 0;
      37     1404174 :     st->final = 0;
      38     1404174 : }
      39             : 
      40     1716365 : static void poly1305_blocks(poly1305_context *st, const unsigned char *m, size_t bytes) noexcept {
      41     1716365 :     const uint32_t hibit = (st->final) ? 0 : (1UL << 24); /* 1 << 128 */
      42             :     uint32_t r0,r1,r2,r3,r4;
      43             :     uint32_t s1,s2,s3,s4;
      44             :     uint32_t h0,h1,h2,h3,h4;
      45             :     uint64_t d0,d1,d2,d3,d4;
      46             :     uint32_t c;
      47             : 
      48     1716365 :     r0 = st->r[0];
      49     1716365 :     r1 = st->r[1];
      50     1716365 :     r2 = st->r[2];
      51     1716365 :     r3 = st->r[3];
      52     1716365 :     r4 = st->r[4];
      53             : 
      54     1716365 :     s1 = r1 * 5;
      55     1716365 :     s2 = r2 * 5;
      56     1716365 :     s3 = r3 * 5;
      57     1716365 :     s4 = r4 * 5;
      58             : 
      59     1716365 :     h0 = st->h[0];
      60     1716365 :     h1 = st->h[1];
      61     1716365 :     h2 = st->h[2];
      62     1716365 :     h3 = st->h[3];
      63     1716365 :     h4 = st->h[4];
      64             : 
      65    42368788 :     while (bytes >= POLY1305_BLOCK_SIZE) {
      66             :         /* h += m[i] */
      67    40652423 :         h0 += (ReadLE32(m+ 0)     ) & 0x3ffffff;
      68    40652423 :         h1 += (ReadLE32(m+ 3) >> 2) & 0x3ffffff;
      69    40652423 :         h2 += (ReadLE32(m+ 6) >> 4) & 0x3ffffff;
      70    40652423 :         h3 += (ReadLE32(m+ 9) >> 6) & 0x3ffffff;
      71    40652423 :         h4 += (ReadLE32(m+12) >> 8) | hibit;
      72             : 
      73             :         /* h *= r */
      74    40652423 :         d0 = ((uint64_t)h0 * r0) + ((uint64_t)h1 * s4) + ((uint64_t)h2 * s3) + ((uint64_t)h3 * s2) + ((uint64_t)h4 * s1);
      75    40652423 :         d1 = ((uint64_t)h0 * r1) + ((uint64_t)h1 * r0) + ((uint64_t)h2 * s4) + ((uint64_t)h3 * s3) + ((uint64_t)h4 * s2);
      76    40652423 :         d2 = ((uint64_t)h0 * r2) + ((uint64_t)h1 * r1) + ((uint64_t)h2 * r0) + ((uint64_t)h3 * s4) + ((uint64_t)h4 * s3);
      77    40652423 :         d3 = ((uint64_t)h0 * r3) + ((uint64_t)h1 * r2) + ((uint64_t)h2 * r1) + ((uint64_t)h3 * r0) + ((uint64_t)h4 * s4);
      78    40652423 :         d4 = ((uint64_t)h0 * r4) + ((uint64_t)h1 * r3) + ((uint64_t)h2 * r2) + ((uint64_t)h3 * r1) + ((uint64_t)h4 * r0);
      79             : 
      80             :         /* (partial) h %= p */
      81    40652423 :                       c = (uint32_t)(d0 >> 26); h0 = (uint32_t)d0 & 0x3ffffff;
      82    40652423 :         d1 += c;      c = (uint32_t)(d1 >> 26); h1 = (uint32_t)d1 & 0x3ffffff;
      83    40652423 :         d2 += c;      c = (uint32_t)(d2 >> 26); h2 = (uint32_t)d2 & 0x3ffffff;
      84    40652423 :         d3 += c;      c = (uint32_t)(d3 >> 26); h3 = (uint32_t)d3 & 0x3ffffff;
      85    40652423 :         d4 += c;      c = (uint32_t)(d4 >> 26); h4 = (uint32_t)d4 & 0x3ffffff;
      86    40652423 :         h0 += c * 5;  c =           (h0 >> 26); h0 =           h0 & 0x3ffffff;
      87    40652423 :         h1 += c;
      88             : 
      89    40652423 :         m += POLY1305_BLOCK_SIZE;
      90    40652423 :         bytes -= POLY1305_BLOCK_SIZE;
      91             :     }
      92             : 
      93     1716365 :     st->h[0] = h0;
      94     1716365 :     st->h[1] = h1;
      95     1716365 :     st->h[2] = h2;
      96     1716365 :     st->h[3] = h3;
      97     1716365 :     st->h[4] = h4;
      98     1716365 : }
      99             : 
     100     1404174 : void poly1305_finish(poly1305_context *st, unsigned char mac[16]) noexcept {
     101             :     uint32_t h0,h1,h2,h3,h4,c;
     102             :     uint32_t g0,g1,g2,g3,g4;
     103             :     uint64_t f;
     104             :     uint32_t mask;
     105             : 
     106             :     /* process the remaining block */
     107     1404174 :     if (st->leftover) {
     108         947 :         size_t i = st->leftover;
     109         947 :         st->buffer[i++] = 1;
     110        7374 :         for (; i < POLY1305_BLOCK_SIZE; i++) {
     111        6427 :             st->buffer[i] = 0;
     112        6427 :         }
     113         947 :         st->final = 1;
     114         947 :         poly1305_blocks(st, st->buffer, POLY1305_BLOCK_SIZE);
     115         947 :     }
     116             : 
     117             :     /* fully carry h */
     118     1404174 :     h0 = st->h[0];
     119     1404174 :     h1 = st->h[1];
     120     1404174 :     h2 = st->h[2];
     121     1404174 :     h3 = st->h[3];
     122     1404174 :     h4 = st->h[4];
     123             : 
     124     1404174 :                  c = h1 >> 26; h1 = h1 & 0x3ffffff;
     125     1404174 :     h2 +=     c; c = h2 >> 26; h2 = h2 & 0x3ffffff;
     126     1404174 :     h3 +=     c; c = h3 >> 26; h3 = h3 & 0x3ffffff;
     127     1404174 :     h4 +=     c; c = h4 >> 26; h4 = h4 & 0x3ffffff;
     128     1404174 :     h0 += c * 5; c = h0 >> 26; h0 = h0 & 0x3ffffff;
     129     1404174 :     h1 +=     c;
     130             : 
     131             :     /* compute h + -p */
     132     1404174 :     g0 = h0 + 5; c = g0 >> 26; g0 &= 0x3ffffff;
     133     1404174 :     g1 = h1 + c; c = g1 >> 26; g1 &= 0x3ffffff;
     134     1404174 :     g2 = h2 + c; c = g2 >> 26; g2 &= 0x3ffffff;
     135     1404174 :     g3 = h3 + c; c = g3 >> 26; g3 &= 0x3ffffff;
     136     1404174 :     g4 = h4 + c - (1UL << 26);
     137             : 
     138             :     /* select h if h < p, or h + -p if h >= p */
     139     1404174 :     mask = (g4 >> ((sizeof(uint32_t) * 8) - 1)) - 1;
     140     1404174 :     g0 &= mask;
     141     1404174 :     g1 &= mask;
     142     1404174 :     g2 &= mask;
     143     1404174 :     g3 &= mask;
     144     1404174 :     g4 &= mask;
     145     1404174 :     mask = ~mask;
     146     1404174 :     h0 = (h0 & mask) | g0;
     147     1404174 :     h1 = (h1 & mask) | g1;
     148     1404174 :     h2 = (h2 & mask) | g2;
     149     1404174 :     h3 = (h3 & mask) | g3;
     150     1404174 :     h4 = (h4 & mask) | g4;
     151             : 
     152             :     /* h = h % (2^128) */
     153     1404174 :     h0 = ((h0      ) | (h1 << 26)) & 0xffffffff;
     154     1404174 :     h1 = ((h1 >>  6) | (h2 << 20)) & 0xffffffff;
     155     1404174 :     h2 = ((h2 >> 12) | (h3 << 14)) & 0xffffffff;
     156     1404174 :     h3 = ((h3 >> 18) | (h4 <<  8)) & 0xffffffff;
     157             : 
     158             :     /* mac = (h + pad) % (2^128) */
     159     1404174 :     f = (uint64_t)h0 + st->pad[0]            ; h0 = (uint32_t)f;
     160     1404174 :     f = (uint64_t)h1 + st->pad[1] + (f >> 32); h1 = (uint32_t)f;
     161     1404174 :     f = (uint64_t)h2 + st->pad[2] + (f >> 32); h2 = (uint32_t)f;
     162     1404174 :     f = (uint64_t)h3 + st->pad[3] + (f >> 32); h3 = (uint32_t)f;
     163             : 
     164     1404174 :     WriteLE32(mac +  0, h0);
     165     1404174 :     WriteLE32(mac +  4, h1);
     166     1404174 :     WriteLE32(mac +  8, h2);
     167     1404174 :     WriteLE32(mac + 12, h3);
     168             : 
     169             :     /* zero out the state */
     170     1404174 :     st->h[0] = 0;
     171     1404174 :     st->h[1] = 0;
     172     1404174 :     st->h[2] = 0;
     173     1404174 :     st->h[3] = 0;
     174     1404174 :     st->h[4] = 0;
     175     1404174 :     st->r[0] = 0;
     176     1404174 :     st->r[1] = 0;
     177     1404174 :     st->r[2] = 0;
     178     1404174 :     st->r[3] = 0;
     179     1404174 :     st->r[4] = 0;
     180     1404174 :     st->pad[0] = 0;
     181     1404174 :     st->pad[1] = 0;
     182     1404174 :     st->pad[2] = 0;
     183     1404174 :     st->pad[3] = 0;
     184     1404174 : }
     185             : 
     186     7020787 : void poly1305_update(poly1305_context *st, const unsigned char *m, size_t bytes) noexcept {
     187             :     size_t i;
     188             : 
     189             :     /* handle leftover */
     190     7020787 :     if (st->leftover) {
     191      192424 :         size_t want = (POLY1305_BLOCK_SIZE - st->leftover);
     192      192424 :         if (want > bytes) {
     193        2965 :             want = bytes;
     194        2965 :         }
     195     2197846 :         for (i = 0; i < want; i++) {
     196     2005422 :             st->buffer[st->leftover + i] = m[i];
     197     2005422 :         }
     198      192424 :         bytes -= want;
     199      192424 :         m += want;
     200      192424 :         st->leftover += want;
     201      192424 :         if (st->leftover < POLY1305_BLOCK_SIZE) return;
     202      189459 :         poly1305_blocks(st, st->buffer, POLY1305_BLOCK_SIZE);
     203      189459 :         st->leftover = 0;
     204      189459 :     }
     205             : 
     206             :     /* process full blocks */
     207     7017822 :     if (bytes >= POLY1305_BLOCK_SIZE) {
     208     1525959 :         size_t want = (bytes & ~(POLY1305_BLOCK_SIZE - 1));
     209     1525959 :         poly1305_blocks(st, m, want);
     210     1525959 :         m += want;
     211     1525959 :         bytes -= want;
     212     1525959 :     }
     213             : 
     214             :     /* store leftover */
     215     7017822 :     if (bytes) {
     216     1224106 :         for (i = 0; i < bytes; i++) {
     217     1033700 :             st->buffer[st->leftover + i] = m[i];
     218     1033700 :         }
     219      190406 :         st->leftover += bytes;
     220      190406 :     }
     221     7020787 : }
     222             : 
     223             : }  // namespace poly1305_donna