mirror of
https://github.com/hrydgard/ppsspp.git
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465 lines
8.5 KiB
C
465 lines
8.5 KiB
C
// Copyright 2007-2022 Segher Boessenkool <segher@kernel.crashing.org>
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// Licensed under the terms of the GNU GPL, either version 2 or version 3
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// https://www.gnu.org/licenses/old-licenses/gpl-2.0.txt
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// https://www.gnu.org/licenses/gpl-3.0.html
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// Modified for Kirk engine by setting single curve and internal function
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// to support Kirk elliptic curve options.- July 2011
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#include <string.h>
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#include <stdio.h>
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// Include definitions from kirk header
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#include "kirk_engine.h"
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struct point {
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u8 x[20];
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u8 y[20];
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};
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// Simplified for use by Kirk Engine since it has only 1 curve
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u8 ec_p[20];
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u8 ec_a[20];
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u8 ec_b[20];
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u8 ec_N[21];
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struct point ec_G; // mon
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struct point ec_Q; // mon
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u8 ec_k[21];
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void hex_dump(char *str, u8 *buf, int size)
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{
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int i;
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if(str)
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printf("%s:", str);
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for(i=0; i<size; i++){
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if((i%32)==0){
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printf("\n%4X:", i);
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}
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printf(" %02X", buf[i]);
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}
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printf("\n\n");
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}
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static void elt_copy(u8 *d, u8 *a)
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{
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memcpy(d, a, 20);
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}
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static void elt_zero(u8 *d)
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{
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memset(d, 0, 20);
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}
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static int elt_is_zero(u8 *d)
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{
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u32 i;
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for (i = 0; i < 20; i++)
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if (d[i] != 0)
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return 0;
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return 1;
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}
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static void elt_add(u8 *d, u8 *a, u8 *b)
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{
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bn_add(d, a, b, ec_p, 20);
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}
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static void elt_sub(u8 *d, u8 *a, u8 *b)
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{
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bn_sub(d, a, b, ec_p, 20);
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}
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static void elt_mul(u8 *d, u8 *a, u8 *b)
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{
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bn_mon_mul(d, a, b, ec_p, 20);
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}
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static void elt_square(u8 *d, u8 *a)
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{
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elt_mul(d, a, a);
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}
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static void elt_inv(u8 *d, u8 *a)
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{
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u8 s[20];
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elt_copy(s, a);
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bn_mon_inv(d, s, ec_p, 20);
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}
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static void point_to_mon(struct point *p)
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{
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bn_to_mon(p->x, ec_p, 20);
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bn_to_mon(p->y, ec_p, 20);
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}
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static void point_from_mon(struct point *p)
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{
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bn_from_mon(p->x, ec_p, 20);
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bn_from_mon(p->y, ec_p, 20);
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}
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#if 0
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static int point_is_on_curve(u8 *p)
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{
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u8 s[20], t[20];
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u8 *x, *y;
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x = p;
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y = p + 20;
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elt_square(t, x);
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elt_mul(s, t, x);
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elt_mul(t, x, ec_a);
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elt_add(s, s, t);
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elt_add(s, s, ec_b);
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elt_square(t, y);
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elt_sub(s, s, t);
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return elt_is_zero(s);
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}
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#endif
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static void point_zero(struct point *p)
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{
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elt_zero(p->x);
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elt_zero(p->y);
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}
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static int point_is_zero(struct point *p)
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{
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return elt_is_zero(p->x) && elt_is_zero(p->y);
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}
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static void point_double(struct point *r, struct point *p)
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{
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u8 s[20], t[20];
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struct point pp;
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u8 *px, *py, *rx, *ry;
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pp = *p;
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px = pp.x;
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py = pp.y;
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rx = r->x;
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ry = r->y;
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if (elt_is_zero(py)) {
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point_zero(r);
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return;
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}
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elt_square(t, px); // t = px*px
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elt_add(s, t, t); // s = 2*px*px
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elt_add(s, s, t); // s = 3*px*px
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elt_add(s, s, ec_a); // s = 3*px*px + a
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elt_add(t, py, py); // t = 2*py
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elt_inv(t, t); // t = 1/(2*py)
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elt_mul(s, s, t); // s = (3*px*px+a)/(2*py)
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elt_square(rx, s); // rx = s*s
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elt_add(t, px, px); // t = 2*px
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elt_sub(rx, rx, t); // rx = s*s - 2*px
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elt_sub(t, px, rx); // t = -(rx-px)
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elt_mul(ry, s, t); // ry = -s*(rx-px)
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elt_sub(ry, ry, py); // ry = -s*(rx-px) - py
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}
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static void point_add(struct point *r, struct point *p, struct point *q)
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{
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u8 s[20], t[20], u[20];
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u8 *px, *py, *qx, *qy, *rx, *ry;
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struct point pp, qq;
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pp = *p;
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qq = *q;
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px = pp.x;
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py = pp.y;
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qx = qq.x;
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qy = qq.y;
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rx = r->x;
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ry = r->y;
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if (point_is_zero(&pp)) {
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elt_copy(rx, qx);
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elt_copy(ry, qy);
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return;
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}
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if (point_is_zero(&qq)) {
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elt_copy(rx, px);
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elt_copy(ry, py);
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return;
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}
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elt_sub(u, qx, px);
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if (elt_is_zero(u)) {
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elt_sub(u, qy, py);
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if (elt_is_zero(u))
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point_double(r, &pp);
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else
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point_zero(r);
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return;
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}
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elt_inv(t, u); // t = 1/(qx-px)
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elt_sub(u, qy, py); // u = qy-py
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elt_mul(s, t, u); // s = (qy-py)/(qx-px)
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elt_square(rx, s); // rx = s*s
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elt_add(t, px, qx); // t = px+qx
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elt_sub(rx, rx, t); // rx = s*s - (px+qx)
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elt_sub(t, px, rx); // t = -(rx-px)
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elt_mul(ry, s, t); // ry = -s*(rx-px)
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elt_sub(ry, ry, py); // ry = -s*(rx-px) - py
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}
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static void point_mul(struct point *d, u8 *a, struct point *b) // a is bignum
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{
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u32 i;
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u8 mask;
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point_zero(d);
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for (i = 0; i < 21; i++)
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for (mask = 0x80; mask != 0; mask >>= 1) {
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point_double(d, d);
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if ((a[i] & mask) != 0)
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point_add(d, d, b);
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}
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}
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// Modified from original to support kirk engine use - July 2011
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// Added call to Kirk Random number generator rather than /dev/random
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static void generate_ecdsa(u8 *outR, u8 *outS, u8 *k, u8 *hash)
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{
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u8 e[21];
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u8 kk[21];
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u8 m[21];
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u8 R[21];
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u8 S[21];
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u8 minv[21];
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struct point mG;
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e[0] = 0;R[0] = 0;S[0] = 0;
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memcpy(e + 1, hash, 20);
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bn_reduce(e, ec_N, 21);
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// Original removed for portability
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//try_again:
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//fp = fopen("/dev/random", "rb");
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//if (fread(m, sizeof m, 1, fp) != 1)
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//fail("reading random");
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//fclose(fp);
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//m[0] = 0;
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//if (bn_compare(m, ec_N, 21) >= 0)
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//goto try_again;
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// R = (mG).x
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// Added call back to kirk PRNG - July 2011
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kirk_CMD14(m+1, 20);
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m[0] = 0;
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point_mul(&mG, m, &ec_G);
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point_from_mon(&mG);
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R[0] = 0;
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elt_copy(R+1, mG.x);
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// S = m**-1*(e + Rk) (mod N)
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bn_copy(kk, k, 21);
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bn_reduce(kk, ec_N, 21);
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bn_to_mon(m, ec_N, 21);
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bn_to_mon(e, ec_N, 21);
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bn_to_mon(R, ec_N, 21);
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bn_to_mon(kk, ec_N, 21);
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bn_mon_mul(S, R, kk, ec_N, 21);
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bn_add(kk, S, e, ec_N, 21);
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bn_mon_inv(minv, m, ec_N, 21);
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bn_mon_mul(S, minv, kk, ec_N, 21);
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bn_from_mon(R, ec_N, 21);
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bn_from_mon(S, ec_N, 21);
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memcpy(outR,R+1,20);
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memcpy(outS,S+1,20);
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}
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// Signing =
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// r = k *G;
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// s = x*r+m / k
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// Verify =
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// r/s * P = m/s * G
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// Slightly modified to support kirk compatible signature input - July 2011
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static int check_ecdsa(struct point *Q, u8 *inR, u8 *inS, u8 *hash)
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{
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u8 Sinv[21];
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u8 e[21], R[21], S[21];
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u8 w1[21], w2[21];
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struct point r1, r2;
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u8 rr[21];
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e[0] = 0;
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memcpy(e + 1, hash, 20);
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bn_reduce(e, ec_N, 21);
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R[0] = 0;
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memcpy(R + 1, inR, 20);
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bn_reduce(R, ec_N, 21);
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S[0] = 0;
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memcpy(S + 1, inS, 20);
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bn_reduce(S, ec_N, 21);
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bn_to_mon(R, ec_N, 21);
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bn_to_mon(S, ec_N, 21);
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bn_to_mon(e, ec_N, 21);
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// make Sinv = 1/S
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bn_mon_inv(Sinv, S, ec_N, 21);
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// w1 = m * Sinv
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bn_mon_mul(w1, e, Sinv, ec_N, 21);
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// w2 = r * Sinv
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bn_mon_mul(w2, R, Sinv, ec_N, 21);
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// mod N both
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bn_from_mon(w1, ec_N, 21);
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bn_from_mon(w2, ec_N, 21);
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// r1 = m/s * G
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point_mul(&r1, w1, &ec_G);
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// r2 = r/s * P
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point_mul(&r2, w2, Q);
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//r1 = r1 + r2
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point_add(&r1, &r1, &r2);
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point_from_mon(&r1);
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rr[0] = 0;
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memcpy(rr + 1, r1.x, 20);
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bn_reduce(rr, ec_N, 21);
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bn_from_mon(R, ec_N, 21);
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bn_from_mon(S, ec_N, 21);
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return (bn_compare(rr, R, 21) == 0);
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}
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// Modified from original to support kirk engine use - July 2011
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void ec_priv_to_pub(u8 *k, u8 *Q)
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{
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struct point ec_temp;
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bn_to_mon(k, ec_N, 21);
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point_mul(&ec_temp, k, &ec_G);
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point_from_mon(&ec_temp);
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//bn_from_mon(k, ec_N, 21);
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memcpy(Q,ec_temp.x,20);
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memcpy(Q+20,ec_temp.y,20);
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}
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// Modified from original to support kirk engine use - July 2011
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void ec_pub_mult(u8 *k, u8 *Q)
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{
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struct point ec_temp;
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//bn_to_mon(k, ec_N, 21);
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point_mul(&ec_temp, k, &ec_Q);
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point_from_mon(&ec_temp);
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//bn_from_mon(k, ec_N, 21);
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memcpy(Q,ec_temp.x,20);
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memcpy(Q+20,ec_temp.y,20);
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}
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// Simplified for use by Kirk Engine - NO LONGER COMPATIABLE WITH ORIGINAL VERSION - July 2011
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int ecdsa_set_curve(u8* p,u8* a,u8* b,u8* N,u8* Gx,u8* Gy)
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{
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memcpy(ec_p,p,20);
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memcpy(ec_a,a,20);
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memcpy(ec_b,b,20);
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memcpy(ec_N,N,21);
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bn_to_mon(ec_a, ec_p, 20);
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bn_to_mon(ec_b, ec_p, 20);
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memcpy(ec_G.x, Gx, 20);
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memcpy(ec_G.y, Gy, 20);
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point_to_mon(&ec_G);
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return 0;
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}
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void ecdsa_set_pub(u8 *Q)
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{
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memcpy(ec_Q.x, Q, 20);
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memcpy(ec_Q.y, Q+20, 20);
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point_to_mon(&ec_Q);
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}
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void ecdsa_set_priv(u8 *ink)
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{
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u8 k[21];
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k[0]=0;
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memcpy(k+1,ink,20);
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bn_reduce(k, ec_N, 21);
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memcpy(ec_k, k, sizeof ec_k);
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}
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int ecdsa_verify(u8 *hash, u8 *R, u8 *S)
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{
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return check_ecdsa(&ec_Q, R, S, hash);
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}
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void ecdsa_sign(u8 *hash, u8 *R, u8 *S)
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{
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generate_ecdsa(R, S, ec_k, hash);
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}
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int point_is_on_curve(u8 *p)
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{
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u8 s[20], t[20];
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u8 *x, *y;
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x = p;
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y = p + 20;
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elt_square(t, x);
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elt_mul(s, t, x);// s = x^3
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elt_mul(t, x, ec_a);
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elt_add(s, s, t); //s = x^3 + a *x
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elt_add(s, s, ec_b);//s = x^3 + a *x + b
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elt_square(t, y); //t = y^2
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elt_sub(s, s, t); // is s - t = 0?
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hex_dump("S", s, 20);
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hex_dump("T", t,20);
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return elt_is_zero(s);
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}
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void dump_ecc(void) {
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hex_dump("P", ec_p, 20);
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hex_dump("a", ec_a, 20);
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hex_dump("b", ec_b, 20);
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hex_dump("N", ec_N, 21);
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hex_dump("Gx", ec_G.x, 20);
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hex_dump("Gy", ec_G.y, 20);
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}
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