diff options
Diffstat (limited to 'third_party/bearssl/src/ec_c25519_m31.c')
| -rw-r--r-- | third_party/bearssl/src/ec_c25519_m31.c | 800 |
1 files changed, 800 insertions, 0 deletions
diff --git a/third_party/bearssl/src/ec_c25519_m31.c b/third_party/bearssl/src/ec_c25519_m31.c new file mode 100644 index 0000000..1dd6d51 --- /dev/null +++ b/third_party/bearssl/src/ec_c25519_m31.c @@ -0,0 +1,800 @@ +/* + * Copyright (c) 2017 Thomas Pornin <[email protected]> + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#include "inner.h" + +/* obsolete +#include <stdio.h> +#include <stdlib.h> +static void +print_int(const char *name, const uint32_t *x) +{ + size_t u; + unsigned char tmp[40]; + + printf("%s = ", name); + for (u = 0; u < 9; u ++) { + if (x[u] > 0x3FFFFFFF) { + printf("INVALID:"); + for (u = 0; u < 9; u ++) { + printf(" %08X", x[u]); + } + printf("\n"); + return; + } + } + memset(tmp, 0, sizeof tmp); + for (u = 0; u < 9; u ++) { + uint64_t w; + int j, k; + + w = x[u]; + j = 30 * (int)u; + k = j & 7; + if (k != 0) { + w <<= k; + j -= k; + } + k = j >> 3; + for (j = 0; j < 8; j ++) { + tmp[39 - k - j] |= (unsigned char)w; + w >>= 8; + } + } + for (u = 8; u < 40; u ++) { + printf("%02X", tmp[u]); + } + printf("\n"); +} +*/ + +/* + * If BR_NO_ARITH_SHIFT is undefined, or defined to 0, then we _assume_ + * that right-shifting a signed negative integer copies the sign bit + * (arithmetic right-shift). This is "implementation-defined behaviour", + * i.e. it is not undefined, but it may differ between compilers. Each + * compiler is supposed to document its behaviour in that respect. GCC + * explicitly defines that an arithmetic right shift is used. We expect + * all other compilers to do the same, because underlying CPU offer an + * arithmetic right shift opcode that could not be used otherwise. + */ +#if BR_NO_ARITH_SHIFT +#define ARSH(x, n) (((uint32_t)(x) >> (n)) \ + | ((-((uint32_t)(x) >> 31)) << (32 - (n)))) +#else +#define ARSH(x, n) ((*(int32_t *)&(x)) >> (n)) +#endif + +/* + * Convert an integer from unsigned little-endian encoding to a sequence of + * 30-bit words in little-endian order. The final "partial" word is + * returned. + */ +static uint32_t +le8_to_le30(uint32_t *dst, const unsigned char *src, size_t len) +{ + uint32_t acc; + int acc_len; + + acc = 0; + acc_len = 0; + while (len -- > 0) { + uint32_t b; + + b = *src ++; + if (acc_len < 22) { + acc |= b << acc_len; + acc_len += 8; + } else { + *dst ++ = (acc | (b << acc_len)) & 0x3FFFFFFF; + acc = b >> (30 - acc_len); + acc_len -= 22; + } + } + return acc; +} + +/* + * Convert an integer (30-bit words, little-endian) to unsigned + * little-endian encoding. The total encoding length is provided; all + * the destination bytes will be filled. + */ +static void +le30_to_le8(unsigned char *dst, size_t len, const uint32_t *src) +{ + uint32_t acc; + int acc_len; + + acc = 0; + acc_len = 0; + while (len -- > 0) { + if (acc_len < 8) { + uint32_t w; + + w = *src ++; + *dst ++ = (unsigned char)(acc | (w << acc_len)); + acc = w >> (8 - acc_len); + acc_len += 22; + } else { + *dst ++ = (unsigned char)acc; + acc >>= 8; + acc_len -= 8; + } + } +} + +/* + * Multiply two integers. Source integers are represented as arrays of + * nine 30-bit words, for values up to 2^270-1. Result is encoded over + * 18 words of 30 bits each. + */ +static void +mul9(uint32_t *d, const uint32_t *a, const uint32_t *b) +{ + /* + * Maximum intermediate result is no more than + * 10376293531797946367, which fits in 64 bits. Reason: + * + * 10376293531797946367 = 9 * (2^30-1)^2 + 9663676406 + * 10376293531797946367 < 9663676407 * 2^30 + * + * Thus, adding together 9 products of 30-bit integers, with + * a carry of at most 9663676406, yields an integer that fits + * on 64 bits and generates a carry of at most 9663676406. + */ + uint64_t t[17]; + uint64_t cc; + int i; + + t[ 0] = MUL31(a[0], b[0]); + t[ 1] = MUL31(a[0], b[1]) + + MUL31(a[1], b[0]); + t[ 2] = MUL31(a[0], b[2]) + + MUL31(a[1], b[1]) + + MUL31(a[2], b[0]); + t[ 3] = MUL31(a[0], b[3]) + + MUL31(a[1], b[2]) + + MUL31(a[2], b[1]) + + MUL31(a[3], b[0]); + t[ 4] = MUL31(a[0], b[4]) + + MUL31(a[1], b[3]) + + MUL31(a[2], b[2]) + + MUL31(a[3], b[1]) + + MUL31(a[4], b[0]); + t[ 5] = MUL31(a[0], b[5]) + + MUL31(a[1], b[4]) + + MUL31(a[2], b[3]) + + MUL31(a[3], b[2]) + + MUL31(a[4], b[1]) + + MUL31(a[5], b[0]); + t[ 6] = MUL31(a[0], b[6]) + + MUL31(a[1], b[5]) + + MUL31(a[2], b[4]) + + MUL31(a[3], b[3]) + + MUL31(a[4], b[2]) + + MUL31(a[5], b[1]) + + MUL31(a[6], b[0]); + t[ 7] = MUL31(a[0], b[7]) + + MUL31(a[1], b[6]) + + MUL31(a[2], b[5]) + + MUL31(a[3], b[4]) + + MUL31(a[4], b[3]) + + MUL31(a[5], b[2]) + + MUL31(a[6], b[1]) + + MUL31(a[7], b[0]); + t[ 8] = MUL31(a[0], b[8]) + + MUL31(a[1], b[7]) + + MUL31(a[2], b[6]) + + MUL31(a[3], b[5]) + + MUL31(a[4], b[4]) + + MUL31(a[5], b[3]) + + MUL31(a[6], b[2]) + + MUL31(a[7], b[1]) + + MUL31(a[8], b[0]); + t[ 9] = MUL31(a[1], b[8]) + + MUL31(a[2], b[7]) + + MUL31(a[3], b[6]) + + MUL31(a[4], b[5]) + + MUL31(a[5], b[4]) + + MUL31(a[6], b[3]) + + MUL31(a[7], b[2]) + + MUL31(a[8], b[1]); + t[10] = MUL31(a[2], b[8]) + + MUL31(a[3], b[7]) + + MUL31(a[4], b[6]) + + MUL31(a[5], b[5]) + + MUL31(a[6], b[4]) + + MUL31(a[7], b[3]) + + MUL31(a[8], b[2]); + t[11] = MUL31(a[3], b[8]) + + MUL31(a[4], b[7]) + + MUL31(a[5], b[6]) + + MUL31(a[6], b[5]) + + MUL31(a[7], b[4]) + + MUL31(a[8], b[3]); + t[12] = MUL31(a[4], b[8]) + + MUL31(a[5], b[7]) + + MUL31(a[6], b[6]) + + MUL31(a[7], b[5]) + + MUL31(a[8], b[4]); + t[13] = MUL31(a[5], b[8]) + + MUL31(a[6], b[7]) + + MUL31(a[7], b[6]) + + MUL31(a[8], b[5]); + t[14] = MUL31(a[6], b[8]) + + MUL31(a[7], b[7]) + + MUL31(a[8], b[6]); + t[15] = MUL31(a[7], b[8]) + + MUL31(a[8], b[7]); + t[16] = MUL31(a[8], b[8]); + + /* + * Propagate carries. + */ + cc = 0; + for (i = 0; i < 17; i ++) { + uint64_t w; + + w = t[i] + cc; + d[i] = (uint32_t)w & 0x3FFFFFFF; + cc = w >> 30; + } + d[17] = (uint32_t)cc; +} + +/* + * Square a 270-bit integer, represented as an array of nine 30-bit words. + * Result uses 18 words of 30 bits each. + */ +static void +square9(uint32_t *d, const uint32_t *a) +{ + uint64_t t[17]; + uint64_t cc; + int i; + + t[ 0] = MUL31(a[0], a[0]); + t[ 1] = ((MUL31(a[0], a[1])) << 1); + t[ 2] = MUL31(a[1], a[1]) + + ((MUL31(a[0], a[2])) << 1); + t[ 3] = ((MUL31(a[0], a[3]) + + MUL31(a[1], a[2])) << 1); + t[ 4] = MUL31(a[2], a[2]) + + ((MUL31(a[0], a[4]) + + MUL31(a[1], a[3])) << 1); + t[ 5] = ((MUL31(a[0], a[5]) + + MUL31(a[1], a[4]) + + MUL31(a[2], a[3])) << 1); + t[ 6] = MUL31(a[3], a[3]) + + ((MUL31(a[0], a[6]) + + MUL31(a[1], a[5]) + + MUL31(a[2], a[4])) << 1); + t[ 7] = ((MUL31(a[0], a[7]) + + MUL31(a[1], a[6]) + + MUL31(a[2], a[5]) + + MUL31(a[3], a[4])) << 1); + t[ 8] = MUL31(a[4], a[4]) + + ((MUL31(a[0], a[8]) + + MUL31(a[1], a[7]) + + MUL31(a[2], a[6]) + + MUL31(a[3], a[5])) << 1); + t[ 9] = ((MUL31(a[1], a[8]) + + MUL31(a[2], a[7]) + + MUL31(a[3], a[6]) + + MUL31(a[4], a[5])) << 1); + t[10] = MUL31(a[5], a[5]) + + ((MUL31(a[2], a[8]) + + MUL31(a[3], a[7]) + + MUL31(a[4], a[6])) << 1); + t[11] = ((MUL31(a[3], a[8]) + + MUL31(a[4], a[7]) + + MUL31(a[5], a[6])) << 1); + t[12] = MUL31(a[6], a[6]) + + ((MUL31(a[4], a[8]) + + MUL31(a[5], a[7])) << 1); + t[13] = ((MUL31(a[5], a[8]) + + MUL31(a[6], a[7])) << 1); + t[14] = MUL31(a[7], a[7]) + + ((MUL31(a[6], a[8])) << 1); + t[15] = ((MUL31(a[7], a[8])) << 1); + t[16] = MUL31(a[8], a[8]); + + /* + * Propagate carries. + */ + cc = 0; + for (i = 0; i < 17; i ++) { + uint64_t w; + + w = t[i] + cc; + d[i] = (uint32_t)w & 0x3FFFFFFF; + cc = w >> 30; + } + d[17] = (uint32_t)cc; +} + +/* + * Perform a "final reduction" in field F255 (field for Curve25519) + * The source value must be less than twice the modulus. If the value + * is not lower than the modulus, then the modulus is subtracted and + * this function returns 1; otherwise, it leaves it untouched and it + * returns 0. + */ +static uint32_t +reduce_final_f255(uint32_t *d) +{ + uint32_t t[9]; + uint32_t cc; + int i; + + memcpy(t, d, sizeof t); + cc = 19; + for (i = 0; i < 9; i ++) { + uint32_t w; + + w = t[i] + cc; + cc = w >> 30; + t[i] = w & 0x3FFFFFFF; + } + cc = t[8] >> 15; + t[8] &= 0x7FFF; + CCOPY(cc, d, t, sizeof t); + return cc; +} + +/* + * Perform a multiplication of two integers modulo 2^255-19. + * Operands are arrays of 9 words, each containing 30 bits of data, in + * little-endian order. Input value may be up to 2^256-1; on output, value + * fits on 256 bits and is lower than twice the modulus. + */ +static void +f255_mul(uint32_t *d, const uint32_t *a, const uint32_t *b) +{ + uint32_t t[18], cc; + int i; + + /* + * Compute raw multiplication. All result words fit in 30 bits + * each; upper word (t[17]) must fit on 2 bits, since the product + * of two 256-bit integers must fit on 512 bits. + */ + mul9(t, a, b); + + /* + * Modular reduction: each high word is added where necessary. + * Since the modulus is 2^255-19 and word 9 corresponds to + * offset 9*30 = 270, word 9+k must be added to word k with + * a factor of 19*2^15 = 622592. The extra bits in word 8 are also + * added that way. + * + * Keeping the carry on 32 bits helps with 32-bit architectures, + * and does not noticeably impact performance on 64-bit systems. + */ + cc = MUL15(t[8] >> 15, 19); /* at most 19*(2^15-1) = 622573 */ + t[8] &= 0x7FFF; + for (i = 0; i < 9; i ++) { + uint64_t w; + + w = (uint64_t)t[i] + (uint64_t)cc + MUL31(t[i + 9], 622592); + t[i] = (uint32_t)w & 0x3FFFFFFF; + cc = (uint32_t)(w >> 30); /* at most 622592 */ + } + + /* + * Original product was up to (2^256-1)^2, i.e. a 512-bit integer. + * This was split into two parts (upper of 257 bits, lower of 255 + * bits), and the upper was added to the lower with a factor 19, + * which means that the intermediate value is less than 77*2^255 + * (19*2^257 + 2^255). Therefore, the extra bits "t[8] >> 15" are + * less than 77, and the initial carry cc is at most 76*19 = 1444. + */ + cc = MUL15(t[8] >> 15, 19); + t[8] &= 0x7FFF; + for (i = 0; i < 9; i ++) { + uint32_t z; + + z = t[i] + cc; + d[i] = z & 0x3FFFFFFF; + cc = z >> 30; + } + + /* + * Final result is at most 2^255 + 1443. In particular, the last + * carry is necessarily 0, since t[8] was truncated to 15 bits. + */ +} + +/* + * Perform a squaring of an integer modulo 2^255-19. + * Operands are arrays of 9 words, each containing 30 bits of data, in + * little-endian order. Input value may be up to 2^256-1; on output, value + * fits on 256 bits and is lower than twice the modulus. + */ +static void +f255_square(uint32_t *d, const uint32_t *a) +{ + uint32_t t[18], cc; + int i; + + /* + * Compute raw squaring. All result words fit in 30 bits + * each; upper word (t[17]) must fit on 2 bits, since the square + * of a 256-bit integers must fit on 512 bits. + */ + square9(t, a); + + /* + * Modular reduction: each high word is added where necessary. + * See f255_mul() for details on the reduction and carry limits. + */ + cc = MUL15(t[8] >> 15, 19); + t[8] &= 0x7FFF; + for (i = 0; i < 9; i ++) { + uint64_t w; + + w = (uint64_t)t[i] + (uint64_t)cc + MUL31(t[i + 9], 622592); + t[i] = (uint32_t)w & 0x3FFFFFFF; + cc = (uint32_t)(w >> 30); + } + cc = MUL15(t[8] >> 15, 19); + t[8] &= 0x7FFF; + for (i = 0; i < 9; i ++) { + uint32_t z; + + z = t[i] + cc; + d[i] = z & 0x3FFFFFFF; + cc = z >> 30; + } +} + +/* + * Add two values in F255. Partial reduction is performed (down to less + * than twice the modulus). + */ +static void +f255_add(uint32_t *d, const uint32_t *a, const uint32_t *b) +{ + /* + * Since operand words fit on 30 bits, we can use 32-bit + * variables throughout. + */ + int i; + uint32_t cc, w; + + cc = 0; + for (i = 0; i < 9; i ++) { + w = a[i] + b[i] + cc; + d[i] = w & 0x3FFFFFFF; + cc = w >> 30; + } + cc = MUL15(w >> 15, 19); + d[8] &= 0x7FFF; + for (i = 0; i < 9; i ++) { + w = d[i] + cc; + d[i] = w & 0x3FFFFFFF; + cc = w >> 30; + } +} + +/* + * Subtract one value from another in F255. Partial reduction is + * performed (down to less than twice the modulus). + */ +static void +f255_sub(uint32_t *d, const uint32_t *a, const uint32_t *b) +{ + /* + * We actually compute a - b + 2*p, so that the final value is + * necessarily positive. + */ + int i; + uint32_t cc, w; + + cc = (uint32_t)-38; + for (i = 0; i < 9; i ++) { + w = a[i] - b[i] + cc; + d[i] = w & 0x3FFFFFFF; + cc = ARSH(w, 30); + } + cc = MUL15((w + 0x10000) >> 15, 19); + d[8] &= 0x7FFF; + for (i = 0; i < 9; i ++) { + w = d[i] + cc; + d[i] = w & 0x3FFFFFFF; + cc = w >> 30; + } +} + +/* + * Multiply an integer by the 'A24' constant (121665). Partial reduction + * is performed (down to less than twice the modulus). + */ +static void +f255_mul_a24(uint32_t *d, const uint32_t *a) +{ + int i; + uint64_t w; + uint32_t cc; + + /* + * a[] is over 256 bits, thus a[8] has length at most 16 bits. + * We single out the processing of the last word: intermediate + * value w is up to 121665*2^16, yielding a carry for the next + * loop of at most 19*(121665*2^16/2^15) = 4623289. + */ + cc = 0; + for (i = 0; i < 8; i ++) { + w = MUL31(a[i], 121665) + (uint64_t)cc; + d[i] = (uint32_t)w & 0x3FFFFFFF; + cc = (uint32_t)(w >> 30); + } + w = MUL31(a[8], 121665) + (uint64_t)cc; + d[8] = (uint32_t)w & 0x7FFF; + cc = MUL15((uint32_t)(w >> 15), 19); + + for (i = 0; i < 9; i ++) { + uint32_t z; + + z = d[i] + cc; + d[i] = z & 0x3FFFFFFF; + cc = z >> 30; + } +} + +static const unsigned char GEN[] = { + 0x09, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 +}; + +static const unsigned char ORDER[] = { + 0x7F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF +}; + +static const unsigned char * +api_generator(int curve, size_t *len) +{ + (void)curve; + *len = 32; + return GEN; +} + +static const unsigned char * +api_order(int curve, size_t *len) +{ + (void)curve; + *len = 32; + return ORDER; +} + +static size_t +api_xoff(int curve, size_t *len) +{ + (void)curve; + *len = 32; + return 0; +} + +static void +cswap(uint32_t *a, uint32_t *b, uint32_t ctl) +{ + int i; + + ctl = -ctl; + for (i = 0; i < 9; i ++) { + uint32_t aw, bw, tw; + + aw = a[i]; + bw = b[i]; + tw = ctl & (aw ^ bw); + a[i] = aw ^ tw; + b[i] = bw ^ tw; + } +} + +static uint32_t +api_mul(unsigned char *G, size_t Glen, + const unsigned char *kb, size_t kblen, int curve) +{ + uint32_t x1[9], x2[9], x3[9], z2[9], z3[9]; + uint32_t a[9], aa[9], b[9], bb[9]; + uint32_t c[9], d[9], e[9], da[9], cb[9]; + unsigned char k[32]; + uint32_t swap; + int i; + + (void)curve; + + /* + * Points are encoded over exactly 32 bytes. Multipliers must fit + * in 32 bytes as well. + * RFC 7748 mandates that the high bit of the last point byte must + * be ignored/cleared. + */ + if (Glen != 32 || kblen > 32) { + return 0; + } + G[31] &= 0x7F; + + /* + * Initialise variables x1, x2, z2, x3 and z3. We set all of them + * into Montgomery representation. + */ + x1[8] = le8_to_le30(x1, G, 32); + memcpy(x3, x1, sizeof x1); + memset(z2, 0, sizeof z2); + memset(x2, 0, sizeof x2); + x2[0] = 1; + memset(z3, 0, sizeof z3); + z3[0] = 1; + + memset(k, 0, (sizeof k) - kblen); + memcpy(k + (sizeof k) - kblen, kb, kblen); + k[31] &= 0xF8; + k[0] &= 0x7F; + k[0] |= 0x40; + + /* obsolete + print_int("x1", x1); + */ + + swap = 0; + for (i = 254; i >= 0; i --) { + uint32_t kt; + + kt = (k[31 - (i >> 3)] >> (i & 7)) & 1; + swap ^= kt; + cswap(x2, x3, swap); + cswap(z2, z3, swap); + swap = kt; + + /* obsolete + print_int("x2", x2); + print_int("z2", z2); + print_int("x3", x3); + print_int("z3", z3); + */ + + f255_add(a, x2, z2); + f255_square(aa, a); + f255_sub(b, x2, z2); + f255_square(bb, b); + f255_sub(e, aa, bb); + f255_add(c, x3, z3); + f255_sub(d, x3, z3); + f255_mul(da, d, a); + f255_mul(cb, c, b); + + /* obsolete + print_int("a ", a); + print_int("aa", aa); + print_int("b ", b); + print_int("bb", bb); + print_int("e ", e); + print_int("c ", c); + print_int("d ", d); + print_int("da", da); + print_int("cb", cb); + */ + + f255_add(x3, da, cb); + f255_square(x3, x3); + f255_sub(z3, da, cb); + f255_square(z3, z3); + f255_mul(z3, z3, x1); + f255_mul(x2, aa, bb); + f255_mul_a24(z2, e); + f255_add(z2, z2, aa); + f255_mul(z2, e, z2); + + /* obsolete + print_int("x2", x2); + print_int("z2", z2); + print_int("x3", x3); + print_int("z3", z3); + */ + } + cswap(x2, x3, swap); + cswap(z2, z3, swap); + + /* + * Inverse z2 with a modular exponentiation. This is a simple + * square-and-multiply algorithm; we mutualise most non-squarings + * since the exponent contains almost only ones. + */ + memcpy(a, z2, sizeof z2); + for (i = 0; i < 15; i ++) { + f255_square(a, a); + f255_mul(a, a, z2); + } + memcpy(b, a, sizeof a); + for (i = 0; i < 14; i ++) { + int j; + + for (j = 0; j < 16; j ++) { + f255_square(b, b); + } + f255_mul(b, b, a); + } + for (i = 14; i >= 0; i --) { + f255_square(b, b); + if ((0xFFEB >> i) & 1) { + f255_mul(b, z2, b); + } + } + f255_mul(x2, x2, b); + reduce_final_f255(x2); + le30_to_le8(G, 32, x2); + return 1; +} + +static size_t +api_mulgen(unsigned char *R, + const unsigned char *x, size_t xlen, int curve) +{ + const unsigned char *G; + size_t Glen; + + G = api_generator(curve, &Glen); + memcpy(R, G, Glen); + api_mul(R, Glen, x, xlen, curve); + return Glen; +} + +static uint32_t +api_muladd(unsigned char *A, const unsigned char *B, size_t len, + const unsigned char *x, size_t xlen, + const unsigned char *y, size_t ylen, int curve) +{ + /* + * We don't implement this method, since it is used for ECDSA + * only, and there is no ECDSA over Curve25519 (which instead + * uses EdDSA). + */ + (void)A; + (void)B; + (void)len; + (void)x; + (void)xlen; + (void)y; + (void)ylen; + (void)curve; + return 0; +} + +/* see bearssl_ec.h */ +const br_ec_impl br_ec_c25519_m31 = { + (uint32_t)0x20000000, + &api_generator, + &api_order, + &api_xoff, + &api_mul, + &api_mulgen, + &api_muladd +}; |