From bccf64ec1b9b1b139259c03907f00d97430d43c5 Mon Sep 17 00:00:00 2001 From: Matthias Schiffer Date: Fri, 7 Dec 2012 19:07:37 +0100 Subject: Reworked the API --- src/ec25519_secret.c | 188 --------------------------------------------------- 1 file changed, 188 deletions(-) delete mode 100644 src/ec25519_secret.c (limited to 'src/ec25519_secret.c') diff --git a/src/ec25519_secret.c b/src/ec25519_secret.c deleted file mode 100644 index 7f3d987..0000000 --- a/src/ec25519_secret.c +++ /dev/null @@ -1,188 +0,0 @@ -/* - Copyright (c) 2012, Matthias Schiffer - Partly based on public domain code by Matthew Dempsky and D. J. Bernstein. - All rights reserved. - - Redistribution and use in source and binary forms, with or without - modification, are permitted provided that the following conditions are met: - - 1. Redistributions of source code must retain the above copyright notice, - this list of conditions and the following disclaimer. - 2. Redistributions in binary form must reproduce the above copyright notice, - this list of conditions and the following disclaimer in the documentation - and/or other materials provided with the distribution. - - THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" - AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE - DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE - FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR - SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER - CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, - OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE - OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -*/ - -/* - Simple finite field operations on the prime field F_q for - q = 2^252 + 27742317777372353535851937790883648493, which - is the order of the base point used for ec25519 -*/ - -#include - - -#define IS_NEGATIVE(n) ((int)((((unsigned)n) >> (8*sizeof(n)-1))&1)) -#define ASR(n,s) (((n) >> s)|(IS_NEGATIVE(n)*((unsigned)-1) << (8*sizeof(n)-s))) - - -static const unsigned char q[32] = { - 0xed, 0xd3, 0xf5, 0x5c, 0x1a, 0x63, 0x12, 0x58, - 0xd6, 0x9c, 0xf7, 0xa2, 0xde, 0xf9, 0xde, 0x14, - 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, - 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10 -}; - - -static void select(unsigned char out[32], const unsigned char r[32], const unsigned char s[32], unsigned int b) { - unsigned int j; - unsigned int t; - unsigned int bminus1; - - bminus1 = b - 1; - for (j = 0;j < 32;++j) { - t = bminus1 & (r[j] ^ s[j]); - out[j] = s[j] ^ t; - } -} - -int ecc_25519_secret_is_zero(const ecc_secret_key_256 *in) { - int i; - ecc_secret_key_256 r; - unsigned int bits; - - ecc_25519_secret_reduce(&r, in); - - for (i = 0; i < 32; i++) - bits |= r.s[i]; - - return (((bits-1)>>8) & 1); -} - -void ecc_25519_secret_add(ecc_secret_key_256 *out, const ecc_secret_key_256 *in1, const ecc_secret_key_256 *in2) { - unsigned int j; - unsigned int u; - int nq = 1 - (in1->s[31]>>4) - (in2->s[31]>>4); - - u = 0; - for (j = 0; j < 32; ++j) { - u += in1->s[j] + in2->s[j] + nq*q[j]; - - out->s[j] = u; - u = ASR(u, 8); - } -} - -void ecc_25519_secret_sub(ecc_secret_key_256 *out, const ecc_secret_key_256 *in1, const ecc_secret_key_256 *in2) { - unsigned int j; - unsigned int u; - int nq = 8 - (in1->s[31]>>4) + (in2->s[31]>>4); - - u = 0; - for (j = 0; j < 32; ++j) { - u += in1->s[j] - in2->s[j] + nq*q[j]; - - out->s[j] = u; - u = ASR(u, 8); - } -} - -static void reduce(unsigned char a[32]) { - unsigned int j; - unsigned int nq = a[31] >> 4; - unsigned int u1, u2; - unsigned char out1[32], out2[32]; - - u1 = u2 = 0; - for (j = 0; j < 31; ++j) { - u1 += a[j] - nq*q[j]; - u2 += a[j] - (nq-1)*q[j]; - - out1[j] = u1; out2[j] = u2; - u1 = ASR(u1, 8); - u2 = ASR(u2, 8); - } - u1 += a[31] - nq*q[31]; - u2 += a[31] - (nq-1)*q[31]; - out1[31] = u1; out2[31] = u2; - - select(a, out1, out2, IS_NEGATIVE(u1)); -} - -void ecc_25519_secret_reduce(ecc_secret_key_256 *out, const ecc_secret_key_256 *in) { - int i; - - for (i = 0; i < 32; i++) - out->s[i] = in->s[i]; - - reduce(out->s); -} - -/* Montgomery modular multiplication algorithm */ -static void montgomery(unsigned char out[32], const unsigned char a[32], const unsigned char b[32]) { - unsigned int i, j; - unsigned int nq; - unsigned int u; - - for (i = 0; i < 32; i++) - out[i] = 0; - - for (i = 0; i < 32; i++) { - u = out[0] + a[i]*b[0]; - nq = (u*27) & 255; - u += nq*q[0]; - - for (j = 1; j < 32; ++j) { - u += (out[j] + a[i]*b[j] + nq*q[j]) << 8; - u >>= 8; - out[j-1] = u; - } - - out[31] = u >> 8; - } -} - - -void ecc_25519_secret_mult(ecc_secret_key_256 *out, const ecc_secret_key_256 *in1, const ecc_secret_key_256 *in2) { - /* 2^512 mod q */ - static const unsigned char C[32] = { - 0x01, 0x0f, 0x9c, 0x44, 0xe3, 0x11, 0x06, 0xa4, - 0x47, 0x93, 0x85, 0x68, 0xa7, 0x1b, 0x0e, 0xd0, - 0x65, 0xbe, 0xf5, 0x17, 0xd2, 0x73, 0xec, 0xce, - 0x3d, 0x9a, 0x30, 0x7c, 0x1b, 0x41, 0x99, 0x03 - }; - - unsigned char B[32]; - unsigned char R[32]; - unsigned int i; - - for (i = 0; i < 32; i++) - B[i] = in2->s[i]; - - reduce(B); - - montgomery(R, in1->s, B); - montgomery(out->s, R, C); -} - -void ecc_25519_secret_sanitize(ecc_secret_key_256 *out, const ecc_secret_key_256 *in) { - int i; - - for (i = 0; i < 32; i++) - out->s[i] = in->s[i]; - - out->s[0] &= 0xf8; - out->s[31] &= 0x7f; - out->s[31] |= 0x40; -} -- cgit v1.2.3