From bd0aa66e454246a1781c27f6d82273e62e121110 Mon Sep 17 00:00:00 2001 From: Martin Willi Date: Tue, 7 Apr 2015 18:12:52 +0200 Subject: [PATCH] curve22519: Add a portable backend implemented in plain C --- .../plugins/curve25519/Makefile.am | 1 + .../plugins/curve25519/curve25519_drv.c | 2 + .../curve25519/curve25519_drv_portable.c | 613 ++++++++++++++++++ .../curve25519/curve25519_drv_portable.h | 31 + 4 files changed, 647 insertions(+) create mode 100644 src/libstrongswan/plugins/curve25519/curve25519_drv_portable.c create mode 100644 src/libstrongswan/plugins/curve25519/curve25519_drv_portable.h diff --git a/src/libstrongswan/plugins/curve25519/Makefile.am b/src/libstrongswan/plugins/curve25519/Makefile.am index a8003128a..e97a61c2c 100644 --- a/src/libstrongswan/plugins/curve25519/Makefile.am +++ b/src/libstrongswan/plugins/curve25519/Makefile.am @@ -13,6 +13,7 @@ endif libstrongswan_curve25519_la_SOURCES = \ curve25519_dh.h curve25519_dh.c \ curve25519_drv.h curve25519_drv.c \ + curve25519_drv_portable.h curve25519_drv_portable.c \ curve25519_plugin.h curve25519_plugin.c libstrongswan_curve25519_la_LDFLAGS = -module -avoid-version diff --git a/src/libstrongswan/plugins/curve25519/curve25519_drv.c b/src/libstrongswan/plugins/curve25519/curve25519_drv.c index 438a24b40..df39e711f 100644 --- a/src/libstrongswan/plugins/curve25519/curve25519_drv.c +++ b/src/libstrongswan/plugins/curve25519/curve25519_drv.c @@ -14,6 +14,7 @@ */ #include "curve25519_drv.h" +#include "curve25519_drv_portable.h" typedef curve25519_drv_t*(*curve25519_drv_create)(); @@ -23,6 +24,7 @@ typedef curve25519_drv_t*(*curve25519_drv_create)(); curve25519_drv_t *curve25519_drv_probe() { curve25519_drv_create drivers[] = { + curve25519_drv_portable_create, }; curve25519_drv_t *driver; int i; diff --git a/src/libstrongswan/plugins/curve25519/curve25519_drv_portable.c b/src/libstrongswan/plugins/curve25519/curve25519_drv_portable.c new file mode 100644 index 000000000..9182de5a7 --- /dev/null +++ b/src/libstrongswan/plugins/curve25519/curve25519_drv_portable.c @@ -0,0 +1,613 @@ +/* + * Copyright (C) 2015 Martin Willi + * Copyright (C) 2015 revosec AG + * + * Based on public domain code by Andrew Moon (curve22519-donna). + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. See . + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY + * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * for more details. + */ + +#include "curve25519_drv_portable.h" + +typedef struct private_curve25519_drv_t private_curve25519_drv_t; + +/** + * Private data of an curve25519_drv_portable_t object. + */ +struct private_curve25519_drv_t { + + /** + * Public curve25519_drv_t interface. + */ + curve25519_drv_t public; + + /** + * Private key + */ + u_char key[CURVE25519_KEY_SIZE]; +}; + +METHOD(curve25519_drv_t, set_key, bool, + private_curve25519_drv_t *this, u_char *key) +{ + memcpy(this->key, key, sizeof(this->key)); + + this->key[0] &= 0xf8; + this->key[31] &= 0x7f; + this->key[31] |= 0x40; + return TRUE; +} + +/** + * OR a 32-bit integer to an unaligned little-endian + */ +static inline void horule32(void *p, uint32_t x) +{ + uint32_t r; + + memcpy(&r, p, sizeof(r)); + r |= htole32(x); + memcpy(p, &r, sizeof(r)); +} + +/** + * Reduce a 32-bit integer to 26 bits + */ +static inline uint32_t rdc26(uint32_t v) +{ + return v & ((1 << 26) - 1); +} + +/** + * Reduce a 32-bit integer to 25 bits + */ +static inline uint32_t rdc25(uint32_t v) +{ + return v & ((1 << 25) - 1); +} + +/** + * Shift right a 64-bit integer by 26 bits + */ +static inline uint32_t sr26(uint64_t v) +{ + return v >> 26; +} + +/** + * Shift right a 64-bit integer by 25 bits + */ +static inline uint32_t sr25(uint64_t v) +{ + return v >> 25; +} + +/** + * Multiply a 64-bit integer with a 32-bit integer + */ +static inline uint64_t mul64(uint64_t a, uint32_t b) +{ + return a * b; +} + +/** + * out = a + b + */ +static inline void add(uint32_t out[10], uint32_t a[10], uint32_t b[10]) +{ + out[0] = a[0] + b[0]; + out[1] = a[1] + b[1]; + out[2] = a[2] + b[2]; + out[3] = a[3] + b[3]; + out[4] = a[4] + b[4]; + out[5] = a[5] + b[5]; + out[6] = a[6] + b[6]; + out[7] = a[7] + b[7]; + out[8] = a[8] + b[8]; + out[9] = a[9] + b[9]; +} + +/** + * out = a - b + */ +static inline void sub(uint32_t out[10], uint32_t a[10], uint32_t b[10]) +{ + uint32_t x; + + x = 0x7ffffda + a[0] - b[0]; out[0] = rdc26(x); + x = 0x3fffffe + a[1] - b[1] + sr26(x); out[1] = rdc25(x); + x = 0x7fffffe + a[2] - b[2] + sr25(x); out[2] = rdc26(x); + x = 0x3fffffe + a[3] - b[3] + sr26(x); out[3] = rdc25(x); + x = 0x7fffffe + a[4] - b[4] + sr25(x); out[4] = rdc26(x); + x = 0x3fffffe + a[5] - b[5] + sr26(x); out[5] = rdc25(x); + x = 0x7fffffe + a[6] - b[6] + sr25(x); out[6] = rdc26(x); + x = 0x3fffffe + a[7] - b[7] + sr26(x); out[7] = rdc25(x); + x = 0x7fffffe + a[8] - b[8] + sr25(x); out[8] = rdc26(x); + x = 0x3fffffe + a[9] - b[9] + sr26(x); out[9] = rdc25(x); + out[0] += sr25(x) * 19; +} + +/** + * out = in * scalar + */ +static void scalar_product(uint32_t out[10], uint32_t in[10], uint32_t scalar) +{ + uint64_t x; + + x = mul64(in[0], scalar); out[0] = rdc26(x); + x = mul64(in[1], scalar) + sr26(x); out[1] = rdc25(x); + x = mul64(in[2], scalar) + sr25(x); out[2] = rdc26(x); + x = mul64(in[3], scalar) + sr26(x); out[3] = rdc25(x); + x = mul64(in[4], scalar) + sr25(x); out[4] = rdc26(x); + x = mul64(in[5], scalar) + sr26(x); out[5] = rdc25(x); + x = mul64(in[6], scalar) + sr25(x); out[6] = rdc26(x); + x = mul64(in[7], scalar) + sr26(x); out[7] = rdc25(x); + x = mul64(in[8], scalar) + sr25(x); out[8] = rdc26(x); + x = mul64(in[9], scalar) + sr26(x); out[9] = rdc25(x); + out[0] += sr25(x) * 19; +} + +/** + * out = a * b + */ +static inline void mul(uint32_t out[10], uint32_t a[10], uint32_t b[10]) +{ + uint32_t r0, r1, r2, r3, r4, r5, r6, r7, r8, r9; + uint32_t s0, s1, s2, s3, s4, s5, s6, s7, s8, s9; + uint64_t m0, m1, m2, m3, m4, m5, m6, m7, m8, m9; + + r0 = b[0]; + r1 = b[1]; + r2 = b[2]; + r3 = b[3]; + r4 = b[4]; + r5 = b[5]; + r6 = b[6]; + r7 = b[7]; + r8 = b[8]; + r9 = b[9]; + + s0 = a[0]; + s1 = a[1]; + s2 = a[2]; + s3 = a[3]; + s4 = a[4]; + s5 = a[5]; + s6 = a[6]; + s7 = a[7]; + s8 = a[8]; + s9 = a[9]; + + m1 = mul64(r0, s1) + mul64(r1, s0); + m3 = mul64(r0, s3) + mul64(r1, s2) + mul64(r2, s1) + mul64(r3, s0); + m5 = mul64(r0, s5) + mul64(r1, s4) + mul64(r2, s3) + mul64(r3, s2) + + mul64(r4, s1) + mul64(r5, s0); + m7 = mul64(r0, s7) + mul64(r1, s6) + mul64(r2, s5) + mul64(r3, s4) + + mul64(r4, s3) + mul64(r5, s2) + mul64(r6, s1) + mul64(r7, s0); + m9 = mul64(r0, s9) + mul64(r1, s8) + mul64(r2, s7) + mul64(r3, s6) + + mul64(r4, s5) + mul64(r5, s4) + mul64(r6, s3) + mul64(r7, s2) + + mul64(r8, s1) + mul64(r9, s0); + + r1 *= 2; + r3 *= 2; + r5 *= 2; + r7 *= 2; + + m0 = mul64(r0, s0); + m2 = mul64(r0, s2) + mul64(r1, s1) + mul64(r2, s0); + m4 = mul64(r0, s4) + mul64(r1, s3) + mul64(r2, s2) + mul64(r3, s1) + + mul64(r4, s0); + m6 = mul64(r0, s6) + mul64(r1, s5) + mul64(r2, s4) + mul64(r3, s3) + + mul64(r4, s2) + mul64(r5, s1) + mul64(r6, s0); + m8 = mul64(r0, s8) + mul64(r1, s7) + mul64(r2, s6) + mul64(r3, s5) + + mul64(r4, s4) + mul64(r5, s3) + mul64(r6, s2) + mul64(r7, s1) + + mul64(r8, s0); + + r1 *= 19; + r2 *= 19; + r3 = (r3 / 2) * 19; + r4 *= 19; + r5 = (r5 / 2) * 19; + r6 *= 19; + r7 = (r7 / 2) * 19; + r8 *= 19; + r9 *= 19; + + m1 += mul64(r9, s2) + mul64(r8, s3) + mul64(r7, s4) + mul64(r6, s5) + + mul64(r5, s6) + mul64(r4, s7) + mul64(r3, s8) + mul64(r2, s9); + m3 += mul64(r9, s4) + mul64(r8, s5) + mul64(r7, s6) + mul64(r6, s7) + + mul64(r5, s8) + mul64(r4, s9); + m5 += mul64(r9, s6) + mul64(r8, s7) + mul64(r7, s8) + mul64(r6, s9); + m7 += mul64(r9, s8) + mul64(r8, s9); + + r3 *= 2; + r5 *= 2; + r7 *= 2; + r9 *= 2; + + m0 += mul64(r9, s1) + mul64(r8, s2) + mul64(r7, s3) + mul64(r6, s4) + + mul64(r5, s5) + mul64(r4, s6) + mul64(r3, s7) + mul64(r2, s8) + + mul64(r1, s9); + m2 += mul64(r9, s3) + mul64(r8, s4) + mul64(r7, s5) + mul64(r6, s6) + + mul64(r5, s7) + mul64(r4, s8) + mul64(r3, s9); + m4 += mul64(r9, s5) + mul64(r8, s6) + mul64(r7, s7) + mul64(r6, s8) + + mul64(r5, s9); + m6 += mul64(r9, s7) + mul64(r8, s8) + mul64(r7, s9); + m8 += mul64(r9, s9); + + m1 += m0 >> 26; r1 = rdc25(m1); + m2 += m1 >> 25; r2 = rdc26(m2); + m3 += m2 >> 26; r3 = rdc25(m3); + m4 += m3 >> 25; r4 = rdc26(m4); + m5 += m4 >> 26; r5 = rdc25(m5); + m6 += m5 >> 25; r6 = rdc26(m6); + m7 += m6 >> 26; r7 = rdc25(m7); + m8 += m7 >> 25; r8 = rdc26(m8); + m9 += m8 >> 26; r9 = rdc25(m9); + m0 = rdc26(m0) + mul64(m9 >> 25, 19); + r0 = rdc26(m0); r1 += m0 >> 26; + + out[0] = r0; + out[1] = r1; + out[2] = r2; + out[3] = r3; + out[4] = r4; + out[5] = r5; + out[6] = r6; + out[7] = r7; + out[8] = r8; + out[9] = r9; +} + +/** + * out = in^(2 * count), inlining + */ +static inline void square_times(uint32_t out[10], uint32_t in[10], int count) +{ + uint32_t r0, r1, r2, r3, r4, r5, r6, r7, r8, r9; + uint32_t d6, d7, d8, d9; + uint64_t m0, m1, m2, m3, m4, m5, m6, m7, m8, m9; + + r0 = in[0]; + r1 = in[1]; + r2 = in[2]; + r3 = in[3]; + r4 = in[4]; + r5 = in[5]; + r6 = in[6]; + r7 = in[7]; + r8 = in[8]; + r9 = in[9]; + + while (count--) + { + m0 = mul64(r0, r0 ); + r0 *= 2; + m1 = mul64(r0, r1 ); + m2 = mul64(r0, r2 ) + mul64(r1, r1 * 2); + r1 *= 2; + m3 = mul64(r0, r3 ) + mul64(r1, r2 ); + m4 = mul64(r0, r4 ) + mul64(r1, r3 * 2) + mul64(r2, r2); + r2 *= 2; + m5 = mul64(r0, r5 ) + mul64(r1, r4 ) + mul64(r2, r3); + m6 = mul64(r0, r6 ) + mul64(r1, r5 * 2) + mul64(r2, r4) + + mul64(r3, r3 * 2); + r3 *= 2; + m7 = mul64(r0, r7 ) + mul64(r1, r6 ) + mul64(r2, r5) + + mul64(r3, r4 ); + m8 = mul64(r0, r8 ) + mul64(r1, r7 * 2) + mul64(r2, r6) + + mul64(r3, r5 * 2) + mul64(r4, r4 ); + m9 = mul64(r0, r9 ) + mul64(r1, r8 ) + mul64(r2, r7) + + mul64(r3, r6 ) + mul64(r4, r5 * 2); + + d6 = r6 * 19; + d7 = r7 * 2 * 19; + d8 = r8 * 19; + d9 = r9 * 2 * 19; + + m0 += mul64(d9, r1 ) + mul64(d8, r2 ) + mul64(d7, r3 ) + + mul64(d6, r4 * 2) + mul64(r5, r5 * 2 * 19); + m1 += mul64(d9, r2 / 2) + mul64(d8, r3 ) + mul64(d7, r4 ) + + mul64(d6, r5 * 2); + m2 += mul64(d9, r3 ) + mul64(d8, r4 * 2) + mul64(d7, r5 * 2) + + mul64(d6, r6 ); + m3 += mul64(d9, r4 ) + mul64(d8, r5 * 2) + mul64(d7, r6 ); + m4 += mul64(d9, r5 * 2) + mul64(d8, r6 * 2) + mul64(d7, r7 ); + m5 += mul64(d9, r6 ) + mul64(d8, r7 * 2); + m6 += mul64(d9, r7 * 2) + mul64(d8, r8 ); + m7 += mul64(d9, r8 ); + m8 += mul64(d9, r9 ); + + m1 += m0 >> 26; r1 = rdc25(m1); + m2 += m1 >> 25; r2 = rdc26(m2); + m3 += m2 >> 26; r3 = rdc25(m3); + m4 += m3 >> 25; r4 = rdc26(m4); + m5 += m4 >> 26; r5 = rdc25(m5); + m6 += m5 >> 25; r6 = rdc26(m6); + m7 += m6 >> 26; r7 = rdc25(m7); + m8 += m7 >> 25; r8 = rdc26(m8); + m9 += m8 >> 26; r9 = rdc25(m9); + m0 = rdc26(m0) + mul64(sr25(m9), 19); + r0 = rdc26(m0); r1 += sr26(m0); + } + + out[0] = r0; + out[1] = r1; + out[2] = r2; + out[3] = r3; + out[4] = r4; + out[5] = r5; + out[6] = r6; + out[7] = r7; + out[8] = r8; + out[9] = r9; +} + +/** + * out = in * in + */ +static void square(uint32_t out[10], uint32_t in[10]) +{ + return square_times(out, in, 1); +} + +/** + * Take a little-endian, 32-byte number and expand it into polynomial form + */ +static void expand(uint32_t out[10], u_char *in) +{ + uint32_t x0, x1, x2, x3, x4, x5, x6, x7; + + x0 = uletoh32(in + 0); + x1 = uletoh32(in + 4); + x2 = uletoh32(in + 8); + x3 = uletoh32(in + 12); + x4 = uletoh32(in + 16); + x5 = uletoh32(in + 20); + x6 = uletoh32(in + 24); + x7 = uletoh32(in + 28); + + out[0] = rdc26( x0 ); + out[1] = rdc25((((uint64_t)x1 << 32) | x0) >> 26); + out[2] = rdc26((((uint64_t)x2 << 32) | x1) >> 19); + out[3] = rdc25((((uint64_t)x3 << 32) | x2) >> 13); + out[4] = rdc26(( x3) >> 6); + out[5] = rdc25( x4 ); + out[6] = rdc26((((uint64_t)x5 << 32) | x4) >> 25); + out[7] = rdc25((((uint64_t)x6 << 32) | x5) >> 19); + out[8] = rdc26((((uint64_t)x7 << 32) | x6) >> 12); + out[9] = rdc25(( x7) >> 6); +} + +/** + * Propagate carries in f + */ +static inline void carry(uint32_t f[10]) +{ + f[1] += f[0] >> 26; f[0] = rdc26(f[0]); + f[2] += f[1] >> 25; f[1] = rdc25(f[1]); + f[3] += f[2] >> 26; f[2] = rdc26(f[2]); + f[4] += f[3] >> 25; f[3] = rdc25(f[3]); + f[5] += f[4] >> 26; f[4] = rdc26(f[4]); + f[6] += f[5] >> 25; f[5] = rdc25(f[5]); + f[7] += f[6] >> 26; f[6] = rdc26(f[6]); + f[8] += f[7] >> 25; f[7] = rdc25(f[7]); + f[9] += f[8] >> 26; f[8] = rdc26(f[8]); +} + +/** + * Take a fully reduced polynomial form number and contract it into a + * little-endian, 32-byte array + */ +static void contract(u_char *out, uint32_t f[10]) +{ + carry(f); + f[0] += 19 * (f[9] >> 25); f[9] = rdc25(f[9]); + carry(f); + f[0] += 19 * (f[9] >> 25); f[9] = rdc25(f[9]); + + /* 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. + */ + f[0] += 19; + carry(f); + f[0] += 19 * (f[9] >> 25); f[9] = rdc25(f[9]); + + /* now between 19 and 2^255-1 in both cases, and offset by 19. */ + f[0] += (1 << 26) - 19; + f[1] += (1 << 25) - 1; + f[2] += (1 << 26) - 1; + f[3] += (1 << 25) - 1; + f[4] += (1 << 26) - 1; + f[5] += (1 << 25) - 1; + f[6] += (1 << 26) - 1; + f[7] += (1 << 25) - 1; + f[8] += (1 << 26) - 1; + f[9] += (1 << 25) - 1; + + /* now between 2^255 and 2^256-20, and offset by 2^255. */ + carry(f); + f[9] = rdc25(f[9]); + + f[1] <<= 2; + f[2] <<= 3; + f[3] <<= 5; + f[4] <<= 6; + f[6] <<= 1; + f[7] <<= 3; + f[8] <<= 4; + f[9] <<= 6; + + memset(out, 0, 32); + horule32(out + 0, f[0]); + horule32(out + 3, f[1]); + horule32(out + 6, f[2]); + horule32(out + 9, f[3]); + horule32(out + 12, f[4]); + horule32(out + 16, f[5]); + horule32(out + 19, f[6]); + horule32(out + 22, f[7]); + horule32(out + 25, f[8]); + horule32(out + 28, f[9]); +} + +/** + * Swap the contents of x and q if swap is non-zero + */ +static void swap_conditional(uint32_t a[10], uint32_t b[10], uint32_t swap) +{ + uint32_t x0, x1, x2, x3, x4, x5, x6, x7, x8, x9; + + swap = -swap; + + x0 = swap & (a[0] ^ b[0]); a[0] ^= x0; b[0] ^= x0; + x1 = swap & (a[1] ^ b[1]); a[1] ^= x1; b[1] ^= x1; + x2 = swap & (a[2] ^ b[2]); a[2] ^= x2; b[2] ^= x2; + x3 = swap & (a[3] ^ b[3]); a[3] ^= x3; b[3] ^= x3; + x4 = swap & (a[4] ^ b[4]); a[4] ^= x4; b[4] ^= x4; + x5 = swap & (a[5] ^ b[5]); a[5] ^= x5; b[5] ^= x5; + x6 = swap & (a[6] ^ b[6]); a[6] ^= x6; b[6] ^= x6; + x7 = swap & (a[7] ^ b[7]); a[7] ^= x7; b[7] ^= x7; + x8 = swap & (a[8] ^ b[8]); a[8] ^= x8; b[8] ^= x8; + x9 = swap & (a[9] ^ b[9]); a[9] ^= x9; b[9] ^= x9; +} + +/* + * In: b = 2^5 - 2^0 + * Out: b = 2^250 - 2^0 + */ +static void pow_two5mtwo0_two250mtwo0(uint32_t b[10]) +{ + uint32_t t0[10], c[10]; + + /* 2^5 - 2^0 */ /* b */ + /* 2^10 - 2^5 */ square_times(t0, b, 5); + /* 2^10 - 2^0 */ mul(b, t0, b); + /* 2^20 - 2^10 */ square_times(t0, b, 10); + /* 2^20 - 2^0 */ mul(c, t0, b); + /* 2^40 - 2^20 */ square_times(t0, c, 20); + /* 2^40 - 2^0 */ mul(t0, t0, c); + /* 2^50 - 2^10 */ square_times(t0, t0, 10); + /* 2^50 - 2^0 */ mul(b, t0, b); + /* 2^100 - 2^50 */ square_times(t0, b, 50); + /* 2^100 - 2^0 */ mul(c, t0, b); + /* 2^200 - 2^100 */ square_times(t0, c, 100); + /* 2^200 - 2^0 */ mul(t0, t0, c); + /* 2^250 - 2^50 */ square_times(t0, t0, 50); + /* 2^250 - 2^0 */ mul(b, t0, b); +} + +/* + * z^(p - 2) = z(2^255 - 21) + */ +static void recip(uint32_t out[10], uint32_t z[10]) +{ + uint32_t a[10], t0[10], b[10]; + + /* 2 */ square(a, z); /* a = 2 */ + /* 8 */ square_times(t0, a, 2); + /* 9 */ mul(b, t0, z); /* b = 9 */ + /* 11 */ mul(a, b, a); /* a = 11 */ + /* 22 */ square(t0, a); + /* 2^5 - 2^0 = 31 */ mul(b, t0, b); + /* 2^250 - 2^0 */ pow_two5mtwo0_two250mtwo0(b); + /* 2^255 - 2^5 */ square_times(b, b, 5); + /* 2^255 - 21 */ mul(out, b, a); +} + +METHOD(curve25519_drv_t, curve25519, bool, + private_curve25519_drv_t *this, u_char *in, u_char *out) +{ + uint32_t nqpqx[10] = {1}, nqpqz[10] = {0}, nqz[10] = {1}, nqx[10]; + uint32_t q[10], qx[10], qpqx[10], qqx[10], zzz[10], zmone[10]; + uint32_t bit, lastbit, i; + + expand(q, in); + memcpy(nqx, q, sizeof(nqx)); + + /* bit 255 is always 0, and bit 254 is always 1, so skip bit 255 and + * start pre-swapped on bit 254 */ + lastbit = 1; + + /* we are doing bits 254..3 in the loop, but are swapping in bits 253..2 */ + for (i = 253; i >= 2; i--) + { + add(qx, nqx, nqz); + sub(nqz, nqx, nqz); + add(qpqx, nqpqx, nqpqz); + sub(nqpqz, nqpqx, nqpqz); + mul(nqpqx, qpqx, nqz); + mul(nqpqz, qx, nqpqz); + add(qqx, nqpqx, nqpqz); + sub(nqpqz, nqpqx, nqpqz); + square(nqpqz, nqpqz); + square(nqpqx, qqx); + mul(nqpqz, nqpqz, q); + square(qx, qx); + square(nqz, nqz); + mul(nqx, qx, nqz); + sub(nqz, qx, nqz); + scalar_product(zzz, nqz, 121665); + add(zzz, zzz, qx); + mul(nqz, nqz, zzz); + + bit = (this->key[i/8] >> (i & 7)) & 1; + swap_conditional(nqx, nqpqx, bit ^ lastbit); + swap_conditional(nqz, nqpqz, bit ^ lastbit); + lastbit = bit; + } + + /* the final 3 bits are always zero, so we only need to double */ + for (i = 0; i < 3; i++) + { + add(qx, nqx, nqz); + sub(nqz, nqx, nqz); + square(qx, qx); + square(nqz, nqz); + mul(nqx, qx, nqz); + sub(nqz, qx, nqz); + scalar_product(zzz, nqz, 121665); + add(zzz, zzz, qx); + mul(nqz, nqz, zzz); + } + + recip(zmone, nqz); + mul(nqz, nqx, zmone); + contract(out, nqz); + + return TRUE; +} + +METHOD(curve25519_drv_t, destroy, void, + private_curve25519_drv_t *this) +{ + memwipe(this->key, sizeof(this->key)); + free(this); +} + +/** + * See header + */ +curve25519_drv_t *curve25519_drv_portable_create() +{ + private_curve25519_drv_t *this; + + INIT(this, + .public = { + .set_key = _set_key, + .curve25519 = _curve25519, + .destroy = _destroy, + }, + ); + + return &this->public; +} diff --git a/src/libstrongswan/plugins/curve25519/curve25519_drv_portable.h b/src/libstrongswan/plugins/curve25519/curve25519_drv_portable.h new file mode 100644 index 000000000..45ad1d904 --- /dev/null +++ b/src/libstrongswan/plugins/curve25519/curve25519_drv_portable.h @@ -0,0 +1,31 @@ +/* + * Copyright (C) 2015 Martin Willi + * Copyright (C) 2015 revosec AG + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. See . + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY + * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * for more details. + */ + +/** + * @defgroup curve25519_drv_portable curve25519_drv_portable + * @{ @ingroup curve25519 + */ + +#include "curve25519_drv.h" + +#ifndef CURVE25519_DRV_PORTABLE_H_ +#define CURVE25519_DRV_PORTABLE_H_ + +/** + * Create a curve25519_drv_portable instance. + */ +curve25519_drv_t *curve25519_drv_portable_create(); + +#endif /** CURVE25519_DRV_PORTABLE_H_ @}*/