diff options
Diffstat (limited to 'src/Specific/CurveParameters/X25519_C64')
-rw-r--r-- | src/Specific/CurveParameters/X25519_C64/scalarmult.c | 309 |
1 files changed, 0 insertions, 309 deletions
diff --git a/src/Specific/CurveParameters/X25519_C64/scalarmult.c b/src/Specific/CurveParameters/X25519_C64/scalarmult.c deleted file mode 100644 index ffe015012..000000000 --- a/src/Specific/CurveParameters/X25519_C64/scalarmult.c +++ /dev/null @@ -1,309 +0,0 @@ -// The synthesized parts are from fiat-crypto, copyright MIT 2017. -// The synthesis framework is released under the MIT license. -// The non-synthesized parts are from curve25519-donna by Adam Langley (Google): -/* Copyright 2008, Google Inc. - * All rights reserved. - * - * Code released into the public domain. - * - * curve25519-donna: Curve25519 elliptic curve, public key function - * - * http://code.google.com/p/curve25519-donna/ - * - * (modified by Andres Erbsen and Jason Gross) - * Adam Langley <agl@imperialviolet.org> - * Parts optimised by floodyberry - * Derived from public domain C code by Daniel J. Bernstein <djb@cr.yp.to> - * - * More information about curve25519 can be found here - * http://cr.yp.to/ecdh.html - * - * djb's sample implementation of curve25519 is written in a special assembly - * language called qhasm and uses the floating point registers. - * - * This is, almost, a clean room reimplementation from the curve25519 paper. It - * uses many of the tricks described therein. Only the crecip function is taken - * from the sample implementation. - */ - -#include <string.h> -#include <stdint.h> - -#include "femul.h" -#include "fesquare.h" -#include "ladderstep.h" - -typedef unsigned int uint128_t __attribute__((mode(TI))); - -#undef force_inline -#define force_inline __attribute__((always_inline)) - -typedef uint8_t u8; -typedef uint64_t limb; -typedef limb felem[5]; - -static void force_inline -fmul(felem output, const felem in2, const felem in) { - uint64_t out[5]; - femul(out, - in2[4], in2[3], in2[2], in2[1], in2[0], - in[4], in[3], in[2], in[1], in[0]); - output[4] = out[0]; - output[3] = out[1]; - output[2] = out[2]; - output[1] = out[3]; - output[0] = out[4]; -} - -static void force_inline -fsquare_times(felem output, const felem in, limb count) { - uint64_t r0 = in[0]; - uint64_t r1 = in[1]; - uint64_t r2 = in[2]; - uint64_t r3 = in[3]; - uint64_t r4 = in[4]; - - do { - uint64_t out[5]; - fesquare(out, r4, r3, r2, r1, r0); - r4 = out[0]; - r3 = out[1]; - r2 = out[2]; - r1 = out[3]; - r0 = out[4]; - } while(--count); - - output[0] = r0; - output[1] = r1; - output[2] = r2; - output[3] = r3; - output[4] = r4; -} - -/* Take a little-endian, 32-byte number and expand it into polynomial form */ -static void -fexpand(limb *output, const u8 *in) { - output[0] = *((const uint64_t *)(in)) & 0x7ffffffffffff; - output[1] = (*((const uint64_t *)(in+6)) >> 3) & 0x7ffffffffffff; - output[2] = (*((const uint64_t *)(in+12)) >> 6) & 0x7ffffffffffff; - output[3] = (*((const uint64_t *)(in+19)) >> 1) & 0x7ffffffffffff; - output[4] = (*((const uint64_t *)(in+25)) >> 4) & 0x7ffffffffffff; -} - -/* Take a fully reduced polynomial form number and contract it into a - * little-endian, 32-byte array - */ -static void -fcontract(u8 *output, const felem input) { - uint128_t t[5]; - - t[0] = input[0]; - t[1] = input[1]; - t[2] = input[2]; - t[3] = input[3]; - t[4] = input[4]; - - t[1] += t[0] >> 51; t[0] &= 0x7ffffffffffff; - t[2] += t[1] >> 51; t[1] &= 0x7ffffffffffff; - t[3] += t[2] >> 51; t[2] &= 0x7ffffffffffff; - t[4] += t[3] >> 51; t[3] &= 0x7ffffffffffff; - t[0] += 19 * (t[4] >> 51); t[4] &= 0x7ffffffffffff; - - t[1] += t[0] >> 51; t[0] &= 0x7ffffffffffff; - t[2] += t[1] >> 51; t[1] &= 0x7ffffffffffff; - t[3] += t[2] >> 51; t[2] &= 0x7ffffffffffff; - t[4] += t[3] >> 51; t[3] &= 0x7ffffffffffff; - t[0] += 19 * (t[4] >> 51); t[4] &= 0x7ffffffffffff; - - /* now t is between 0 and 2^255-1, properly carried. */ - /* case 1: between 0 and 2^255-20. case 2: between 2^255-19 and 2^255-1. */ - - t[0] += 19; - - t[1] += t[0] >> 51; t[0] &= 0x7ffffffffffff; - t[2] += t[1] >> 51; t[1] &= 0x7ffffffffffff; - t[3] += t[2] >> 51; t[2] &= 0x7ffffffffffff; - t[4] += t[3] >> 51; t[3] &= 0x7ffffffffffff; - t[0] += 19 * (t[4] >> 51); t[4] &= 0x7ffffffffffff; - - /* now between 19 and 2^255-1 in both cases, and offset by 19. */ - - t[0] += 0x8000000000000 - 19; - t[1] += 0x8000000000000 - 1; - t[2] += 0x8000000000000 - 1; - t[3] += 0x8000000000000 - 1; - t[4] += 0x8000000000000 - 1; - - /* now between 2^255 and 2^256-20, and offset by 2^255. */ - - t[1] += t[0] >> 51; t[0] &= 0x7ffffffffffff; - t[2] += t[1] >> 51; t[1] &= 0x7ffffffffffff; - t[3] += t[2] >> 51; t[2] &= 0x7ffffffffffff; - t[4] += t[3] >> 51; t[3] &= 0x7ffffffffffff; - t[4] &= 0x7ffffffffffff; - - *((uint64_t *)(output)) = t[0] | (t[1] << 51); - *((uint64_t *)(output+8)) = (t[1] >> 13) | (t[2] << 38); - *((uint64_t *)(output+16)) = (t[2] >> 26) | (t[3] << 25); - *((uint64_t *)(output+24)) = (t[3] >> 39) | (t[4] << 12); -} - -/* Input: Q, Q', Q-Q' - * Output: 2Q, Q+Q' - */ -static void -fmonty(limb *x2, limb *z2, /* output 2Q */ - limb *x3, limb *z3, /* output Q + Q' */ - limb *x, limb *z, /* input Q */ - limb *xprime, limb *zprime, /* input Q' */ - const limb *qmqp /* input Q - Q' */) { - uint64_t out[20]; - ladderstep(out, qmqp[4], qmqp[3], qmqp[2], qmqp[1], qmqp[0], x[4], x[3], x[2], x[1], x[0], z[4], z[3], z[2], z[1], z[0], xprime[4], xprime[3], xprime[2], xprime[1], xprime[0], zprime[4], zprime[3], zprime[2], zprime[1], zprime[0]); - x2[4] = out[ 0]; - x2[3] = out[ 1]; - x2[2] = out[ 2]; - x2[1] = out[ 3]; - x2[0] = out[ 4]; - z2[4] = out[ 5]; - z2[3] = out[ 6]; - z2[2] = out[ 7]; - z2[1] = out[ 8]; - z2[0] = out[ 9]; - x3[4] = out[10]; - x3[3] = out[11]; - x3[2] = out[12]; - x3[1] = out[13]; - x3[0] = out[14]; - z3[4] = out[15]; - z3[3] = out[16]; - z3[2] = out[17]; - z3[1] = out[18]; - z3[0] = out[19]; -} - -// ----------------------------------------------------------------------------- -// Maybe swap the contents of two limb arrays (@a and @b), each @len elements -// long. Perform the swap iff @swap is non-zero. -// -// This function performs the swap without leaking any side-channel -// information. -// ----------------------------------------------------------------------------- -static void -swap_conditional(limb a[5], limb b[5], limb iswap) { - unsigned i; - const limb swap = -iswap; - - for (i = 0; i < 5; ++i) { - const limb x = swap & (a[i] ^ b[i]); - a[i] ^= x; - b[i] ^= x; - } -} - -/* Calculates nQ where Q is the x-coordinate of a point on the curve - * - * resultx/resultz: the x coordinate of the resulting curve point (short form) - * n: a little endian, 32-byte number - * q: a point of the curve (short form) - */ -static void -cmult(limb *resultx, limb *resultz, const u8 *n, const limb *q) { - limb a[5] = {0}, b[5] = {1}, c[5] = {1}, d[5] = {0}; - limb *nqpqx = a, *nqpqz = b, *nqx = c, *nqz = d, *t; - limb e[5] = {0}, f[5] = {1}, g[5] = {0}, h[5] = {1}; - limb *nqpqx2 = e, *nqpqz2 = f, *nqx2 = g, *nqz2 = h; - - unsigned i, j; - - memcpy(nqpqx, q, sizeof(limb) * 5); - - for (i = 0; i < 32; ++i) { - u8 byte = n[31 - i]; - for (j = 0; j < 8; ++j) { - const limb bit = byte >> 7; - - swap_conditional(nqx, nqpqx, bit); - swap_conditional(nqz, nqpqz, bit); - fmonty(nqx2, nqz2, - nqpqx2, nqpqz2, - nqx, nqz, - nqpqx, nqpqz, - q); - swap_conditional(nqx2, nqpqx2, bit); - swap_conditional(nqz2, nqpqz2, bit); - - t = nqx; - nqx = nqx2; - nqx2 = t; - t = nqz; - nqz = nqz2; - nqz2 = t; - t = nqpqx; - nqpqx = nqpqx2; - nqpqx2 = t; - t = nqpqz; - nqpqz = nqpqz2; - nqpqz2 = t; - - byte <<= 1; - } - } - - memcpy(resultx, nqx, sizeof(limb) * 5); - memcpy(resultz, nqz, sizeof(limb) * 5); -} - - -// ----------------------------------------------------------------------------- -// Shamelessly copied from djb's code, tightened a little -// ----------------------------------------------------------------------------- -static void -crecip(felem out, const felem z) { - felem a,t0,b,c; - - /* 2 */ fsquare_times(a, z, 1); // a = 2 - /* 8 */ fsquare_times(t0, a, 2); - /* 9 */ fmul(b, t0, z); // b = 9 - /* 11 */ fmul(a, b, a); // a = 11 - /* 22 */ fsquare_times(t0, a, 1); - /* 2^5 - 2^0 = 31 */ fmul(b, t0, b); - /* 2^10 - 2^5 */ fsquare_times(t0, b, 5); - /* 2^10 - 2^0 */ fmul(b, t0, b); - /* 2^20 - 2^10 */ fsquare_times(t0, b, 10); - /* 2^20 - 2^0 */ fmul(c, t0, b); - /* 2^40 - 2^20 */ fsquare_times(t0, c, 20); - /* 2^40 - 2^0 */ fmul(t0, t0, c); - /* 2^50 - 2^10 */ fsquare_times(t0, t0, 10); - /* 2^50 - 2^0 */ fmul(b, t0, b); - /* 2^100 - 2^50 */ fsquare_times(t0, b, 50); - /* 2^100 - 2^0 */ fmul(c, t0, b); - /* 2^200 - 2^100 */ fsquare_times(t0, c, 100); - /* 2^200 - 2^0 */ fmul(t0, t0, c); - /* 2^250 - 2^50 */ fsquare_times(t0, t0, 50); - /* 2^250 - 2^0 */ fmul(t0, t0, b); - /* 2^255 - 2^5 */ fsquare_times(t0, t0, 5); - /* 2^255 - 21 */ fmul(out, t0, a); -} - -int -crypto_scalarmult(u8 *mypublic, const u8 *secret, const u8 *basepoint) { - limb bp[5], x[5], z[5], zmone[5]; - uint8_t e[32]; - int i; - - for (i = 0;i < 32;++i) e[i] = secret[i]; - e[0] &= 248; - e[31] &= 127; - e[31] |= 64; - - fexpand(bp, basepoint); - cmult(x, z, e, bp); - crecip(zmone, z); - fmul(z, x, zmone); - fcontract(mypublic, z); - return 0; -} - -void crypto_scalarmult_bench(unsigned char* buf) { - crypto_scalarmult(buf, buf+32, buf+64); -} |