diff options
author | Micah Anderson <micah@riseup.net> | 2014-08-11 13:49:21 -0400 |
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committer | Micah Anderson <micah@riseup.net> | 2014-08-11 13:49:21 -0400 |
commit | 2e59f9740a29439df7c7a56cf0ae83dec3081d31 (patch) | |
tree | d5e7c4e74c9a0f1ea999327d2e68b1dd27be00e0 /src/libsodium/crypto_scalarmult/curve25519/donna_c64 |
initial import of debian version from mentors0.6.1
Diffstat (limited to 'src/libsodium/crypto_scalarmult/curve25519/donna_c64')
3 files changed, 478 insertions, 0 deletions
diff --git a/src/libsodium/crypto_scalarmult/curve25519/donna_c64/api.h b/src/libsodium/crypto_scalarmult/curve25519/donna_c64/api.h new file mode 100644 index 0000000..5c9bba7 --- /dev/null +++ b/src/libsodium/crypto_scalarmult/curve25519/donna_c64/api.h @@ -0,0 +1,9 @@ + +#include "crypto_scalarmult_curve25519.h" + +#define crypto_scalarmult_curve25519_implementation_name \ + crypto_scalarmult_curve25519_donna_c64_implementation_name + +#define crypto_scalarmult crypto_scalarmult_curve25519 +#define crypto_scalarmult_base crypto_scalarmult_curve25519_base + diff --git a/src/libsodium/crypto_scalarmult/curve25519/donna_c64/base_curve25519_donna_c64.c b/src/libsodium/crypto_scalarmult/curve25519/donna_c64/base_curve25519_donna_c64.c new file mode 100644 index 0000000..58a3f1c --- /dev/null +++ b/src/libsodium/crypto_scalarmult/curve25519/donna_c64/base_curve25519_donna_c64.c @@ -0,0 +1,13 @@ + +#include "api.h" + +#ifdef HAVE_TI_MODE + +static const unsigned char basepoint[32] = {9}; + +int crypto_scalarmult_base(unsigned char *q,const unsigned char *n) +{ + return crypto_scalarmult(q, n, basepoint); +} + +#endif diff --git a/src/libsodium/crypto_scalarmult/curve25519/donna_c64/smult_curve25519_donna_c64.c b/src/libsodium/crypto_scalarmult/curve25519/donna_c64/smult_curve25519_donna_c64.c new file mode 100644 index 0000000..c26ea73 --- /dev/null +++ b/src/libsodium/crypto_scalarmult/curve25519/donna_c64/smult_curve25519_donna_c64.c @@ -0,0 +1,456 @@ +/* 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/ + * + * 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 "api.h" + +#ifdef HAVE_TI_MODE + +typedef uint8_t u8; +typedef uint64_t limb; +typedef limb felem[5]; +// This is a special gcc mode for 128-bit integers. It's implemented on 64-bit +// platforms only as far as I know. +typedef unsigned uint128_t __attribute__((mode(TI))); + +#undef force_inline +#define force_inline inline __attribute__((always_inline)) + +/* Sum two numbers: output += in */ +static force_inline void +fsum(limb *output, const limb *in) { + output[0] += in[0]; + output[1] += in[1]; + output[2] += in[2]; + output[3] += in[3]; + output[4] += in[4]; +} + +/* Find the difference of two numbers: output = in - output + * (note the order of the arguments!) + * + * Assumes that out[i] < 2**52 + * On return, out[i] < 2**55 + */ +static force_inline void +fdifference_backwards(felem out, const felem in) { + /* 152 is 19 << 3 */ + static const limb two54m152 = (((limb)1) << 54) - 152; + static const limb two54m8 = (((limb)1) << 54) - 8; + + out[0] = in[0] + two54m152 - out[0]; + out[1] = in[1] + two54m8 - out[1]; + out[2] = in[2] + two54m8 - out[2]; + out[3] = in[3] + two54m8 - out[3]; + out[4] = in[4] + two54m8 - out[4]; +} + +/* Multiply a number by a scalar: output = in * scalar */ +static force_inline void +fscalar_product(felem output, const felem in, const limb scalar) { + uint128_t a; + + a = ((uint128_t) in[0]) * scalar; + output[0] = ((limb)a) & 0x7ffffffffffff; + + a = ((uint128_t) in[1]) * scalar + ((limb) (a >> 51)); + output[1] = ((limb)a) & 0x7ffffffffffff; + + a = ((uint128_t) in[2]) * scalar + ((limb) (a >> 51)); + output[2] = ((limb)a) & 0x7ffffffffffff; + + a = ((uint128_t) in[3]) * scalar + ((limb) (a >> 51)); + output[3] = ((limb)a) & 0x7ffffffffffff; + + a = ((uint128_t) in[4]) * scalar + ((limb) (a >> 51)); + output[4] = ((limb)a) & 0x7ffffffffffff; + + output[0] += (a >> 51) * 19; +} + +/* Multiply two numbers: output = in2 * in + * + * output must be distinct to both inputs. The inputs are reduced coefficient + * form, the output is not. + * + * Assumes that in[i] < 2**55 and likewise for in2. + * On return, output[i] < 2**52 + */ +static force_inline void +fmul(felem output, const felem in2, const felem in) { + uint128_t t[5]; + limb r0,r1,r2,r3,r4,s0,s1,s2,s3,s4,c; + + r0 = in[0]; + r1 = in[1]; + r2 = in[2]; + r3 = in[3]; + r4 = in[4]; + + s0 = in2[0]; + s1 = in2[1]; + s2 = in2[2]; + s3 = in2[3]; + s4 = in2[4]; + + t[0] = ((uint128_t) r0) * s0; + t[1] = ((uint128_t) r0) * s1 + ((uint128_t) r1) * s0; + t[2] = ((uint128_t) r0) * s2 + ((uint128_t) r2) * s0 + ((uint128_t) r1) * s1; + t[3] = ((uint128_t) r0) * s3 + ((uint128_t) r3) * s0 + ((uint128_t) r1) * s2 + ((uint128_t) r2) * s1; + t[4] = ((uint128_t) r0) * s4 + ((uint128_t) r4) * s0 + ((uint128_t) r3) * s1 + ((uint128_t) r1) * s3 + ((uint128_t) r2) * s2; + + r4 *= 19; + r1 *= 19; + r2 *= 19; + r3 *= 19; + + t[0] += ((uint128_t) r4) * s1 + ((uint128_t) r1) * s4 + ((uint128_t) r2) * s3 + ((uint128_t) r3) * s2; + t[1] += ((uint128_t) r4) * s2 + ((uint128_t) r2) * s4 + ((uint128_t) r3) * s3; + t[2] += ((uint128_t) r4) * s3 + ((uint128_t) r3) * s4; + t[3] += ((uint128_t) r4) * s4; + + r0 = (limb)t[0] & 0x7ffffffffffff; c = (limb)(t[0] >> 51); + t[1] += c; r1 = (limb)t[1] & 0x7ffffffffffff; c = (limb)(t[1] >> 51); + t[2] += c; r2 = (limb)t[2] & 0x7ffffffffffff; c = (limb)(t[2] >> 51); + t[3] += c; r3 = (limb)t[3] & 0x7ffffffffffff; c = (limb)(t[3] >> 51); + t[4] += c; r4 = (limb)t[4] & 0x7ffffffffffff; c = (limb)(t[4] >> 51); + r0 += c * 19; c = r0 >> 51; r0 = r0 & 0x7ffffffffffff; + r1 += c; c = r1 >> 51; r1 = r1 & 0x7ffffffffffff; + r2 += c; + + output[0] = r0; + output[1] = r1; + output[2] = r2; + output[3] = r3; + output[4] = r4; +} + +static force_inline void +fsquare_times(felem output, const felem in, limb count) { + uint128_t t[5]; + limb r0,r1,r2,r3,r4,c; + limb d0,d1,d2,d4,d419; + + r0 = in[0]; + r1 = in[1]; + r2 = in[2]; + r3 = in[3]; + r4 = in[4]; + + do { + d0 = r0 * 2; + d1 = r1 * 2; + d2 = r2 * 2 * 19; + d419 = r4 * 19; + d4 = d419 * 2; + + t[0] = ((uint128_t) r0) * r0 + ((uint128_t) d4) * r1 + (((uint128_t) d2) * (r3 )); + t[1] = ((uint128_t) d0) * r1 + ((uint128_t) d4) * r2 + (((uint128_t) r3) * (r3 * 19)); + t[2] = ((uint128_t) d0) * r2 + ((uint128_t) r1) * r1 + (((uint128_t) d4) * (r3 )); + t[3] = ((uint128_t) d0) * r3 + ((uint128_t) d1) * r2 + (((uint128_t) r4) * (d419 )); + t[4] = ((uint128_t) d0) * r4 + ((uint128_t) d1) * r3 + (((uint128_t) r2) * (r2 )); + + r0 = (limb)t[0] & 0x7ffffffffffff; c = (limb)(t[0] >> 51); + t[1] += c; r1 = (limb)t[1] & 0x7ffffffffffff; c = (limb)(t[1] >> 51); + t[2] += c; r2 = (limb)t[2] & 0x7ffffffffffff; c = (limb)(t[2] >> 51); + t[3] += c; r3 = (limb)t[3] & 0x7ffffffffffff; c = (limb)(t[3] >> 51); + t[4] += c; r4 = (limb)t[4] & 0x7ffffffffffff; c = (limb)(t[4] >> 51); + r0 += c * 19; c = r0 >> 51; r0 = r0 & 0x7ffffffffffff; + r1 += c; c = r1 >> 51; r1 = r1 & 0x7ffffffffffff; + r2 += c; + } while(--count); + + output[0] = r0; + output[1] = r1; + output[2] = r2; + output[3] = r3; + output[4] = r4; +} + +#if !defined(CPU_ALIGNED_ACCESS_REQUIRED) && defined(NATIVE_LITTLE_ENDIAN) +# define U8TO64(p) (*((const uint64_t *) (p))) +# define U64TO8(p, v) (*((uint64_t *) (p)) = (v)) +#else +static force_inline uint64_t +U8TO64(const unsigned char *p) { + return + (((uint64_t)(p[0] & 0xff) ) | + ((uint64_t)(p[1] & 0xff) << 8) | + ((uint64_t)(p[2] & 0xff) << 16) | + ((uint64_t)(p[3] & 0xff) << 24) | + ((uint64_t)(p[4] & 0xff) << 32) | + ((uint64_t)(p[5] & 0xff) << 40) | + ((uint64_t)(p[6] & 0xff) << 48) | + ((uint64_t)(p[7] & 0xff) << 56)); +} + +static force_inline void +U64TO8(unsigned char *p, uint64_t v) { + p[0] = (v ) & 0xff; + p[1] = (v >> 8) & 0xff; + p[2] = (v >> 16) & 0xff; + p[3] = (v >> 24) & 0xff; + p[4] = (v >> 32) & 0xff; + p[5] = (v >> 40) & 0xff; + p[6] = (v >> 48) & 0xff; + p[7] = (v >> 56) & 0xff; +} +#endif + +/* Take a little-endian, 32-byte number and expand it into polynomial form */ +static void +fexpand(limb *output, const u8 *in) { + output[0] = U8TO64(in) & 0x7ffffffffffff; + output[1] = (U8TO64(in+6) >> 3) & 0x7ffffffffffff; + output[2] = (U8TO64(in+12) >> 6) & 0x7ffffffffffff; + output[3] = (U8TO64(in+19) >> 1) & 0x7ffffffffffff; + output[4] = (U8TO64(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; + + U64TO8(output, t[0] | (t[1] << 51)); + U64TO8(output + 8, (t[1] >> 13) | (t[2] << 38)); + U64TO8(output + 16, (t[2] >> 26) | (t[3] << 25)); + U64TO8(output + 24, (t[3] >> 39) | (t[4] << 12)); +} + +/* Input: Q, Q', Q-Q' + * Output: 2Q, Q+Q' + * + * x2 z3: long form + * x3 z3: long form + * x z: short form, destroyed + * xprime zprime: short form, destroyed + * qmqp: short form, preserved + */ +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' */) { + limb origx[5], origxprime[5], zzz[5], xx[5], zz[5], xxprime[5], + zzprime[5], zzzprime[5]; + + memcpy(origx, x, 5 * sizeof(limb)); + fsum(x, z); + fdifference_backwards(z, origx); // does x - z + + memcpy(origxprime, xprime, sizeof(limb) * 5); + fsum(xprime, zprime); + fdifference_backwards(zprime, origxprime); + fmul(xxprime, xprime, z); + fmul(zzprime, x, zprime); + memcpy(origxprime, xxprime, sizeof(limb) * 5); + fsum(xxprime, zzprime); + fdifference_backwards(zzprime, origxprime); + fsquare_times(x3, xxprime, 1); + fsquare_times(zzzprime, zzprime, 1); + fmul(z3, zzzprime, qmqp); + + fsquare_times(xx, x, 1); + fsquare_times(zz, z, 1); + fmul(x2, xx, zz); + fdifference_backwards(zz, xx); // does zz = xx - zz + fscalar_product(zzz, zz, 121665); + fsum(zzz, xx); + fmul(z2, zz, zzz); +} + +// ----------------------------------------------------------------------------- +// 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; +} + +#endif |