X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/ba6e6b64033b1f9de49feccb5c9cd438354481f7..0f00dc4c8eb47e67bc0f148c2dd109f73a451e0a:/ec-bin.c diff --git a/ec-bin.c b/ec-bin.c deleted file mode 100644 index 8ba7354..0000000 --- a/ec-bin.c +++ /dev/null @@ -1,447 +0,0 @@ -/* -*-c-*- - * - * $Id$ - * - * Arithmetic for elliptic curves over binary fields - * - * (c) 2004 Straylight/Edgeware - */ - -/*----- Licensing notice --------------------------------------------------* - * - * This file is part of Catacomb. - * - * Catacomb is free software; you can redistribute it and/or modify - * it under the terms of the GNU Library General Public License as - * published by the Free Software Foundation; either version 2 of the - * License, or (at your option) any later version. - * - * Catacomb 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 Library General Public License for more details. - * - * You should have received a copy of the GNU Library General Public - * License along with Catacomb; if not, write to the Free - * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, - * MA 02111-1307, USA. - */ - -/*----- Header files ------------------------------------------------------*/ - -#include - -#include "ec.h" -#include "ec-guts.h" - -/*----- Main code ---------------------------------------------------------*/ - -static const ec_ops ec_binops, ec_binprojops; - -static ec *ecneg(ec_curve *c, ec *d, const ec *p) -{ - EC_COPY(d, p); - if (d->x) - d->y = F_ADD(c->f, d->y, d->y, d->x); - return (d); -} - -static ec *ecprojneg(ec_curve *c, ec *d, const ec *p) -{ - EC_COPY(d, p); - if (d->x) { - mp *t = F_MUL(c->f, MP_NEW, d->x, d->z); - d->y = F_ADD(c->f, d->y, d->y, t); - MP_DROP(t); - } - return (d); -} - -static ec *ecfind(ec_curve *c, ec *d, mp *x) -{ - field *f = c->f; - mp *y, *u, *v; - - if (F_ZEROP(f, x)) - y = F_SQRT(f, MP_NEW, c->b); - else { - u = F_SQR(f, MP_NEW, x); /* %$x^2$% */ - y = F_MUL(f, MP_NEW, u, c->a); /* %$a x^2$% */ - y = F_ADD(f, y, y, c->b); /* %$a x^2 + b$% */ - v = F_MUL(f, MP_NEW, u, x); /* %$x^3$% */ - y = F_ADD(f, y, y, v); /* %$A = x^3 + a x^2 + b$% */ - if (!F_ZEROP(f, y)) { - u = F_INV(f, u, u); /* %$x^{-2}$% */ - v = F_MUL(f, v, u, y); /* %$B = A x^{-2} = x + a + b x^{-2}$% */ - y = F_QUADSOLVE(f, y, v); /* %$z^2 + z = B$% */ - if (y) y = F_MUL(f, y, y, x); /* %$y = z x$% */ - } - MP_DROP(u); - MP_DROP(v); - } - if (!y) return (0); - EC_DESTROY(d); - d->x = MP_COPY(x); - d->y = y; - d->z = MP_COPY(f->one); - return (d); -} - -static ec *ecdbl(ec_curve *c, ec *d, const ec *a) -{ - if (EC_ATINF(a) || F_ZEROP(c->f, a->x)) - EC_SETINF(d); - else { - field *f = c->f; - mp *lambda; - mp *dx, *dy; - - dx = F_INV(f, MP_NEW, a->x); /* %$x^{-1}$% */ - dy = F_MUL(f, MP_NEW, dx, a->y); /* %$y/x$% */ - lambda = F_ADD(f, dy, dy, a->x); /* %$\lambda = x + y/x$% */ - - dx = F_SQR(f, dx, lambda); /* %$\lambda^2$% */ - dx = F_ADD(f, dx, dx, lambda); /* %$\lambda^2 + \lambda$% */ - dx = F_ADD(f, dx, dx, c->a); /* %$x' = a + \lambda^2 + \lambda$% */ - - dy = F_ADD(f, MP_NEW, a->x, dx); /* %$ x + x' $% */ - dy = F_MUL(f, dy, dy, lambda); /* %$ (x + x') \lambda$% */ - dy = F_ADD(f, dy, dy, a->y); /* %$ (x + x') \lambda + y$% */ - dy = F_ADD(f, dy, dy, dx); /* %$ y' = (x + x') \lambda + y + x'$% */ - - EC_DESTROY(d); - d->x = dx; - d->y = dy; - d->z = 0; - MP_DROP(lambda); - } - return (d); -} - -static ec *ecprojdbl(ec_curve *c, ec *d, const ec *a) -{ - if (EC_ATINF(a) || F_ZEROP(c->f, a->x)) - EC_SETINF(d); - else { - field *f = c->f; - ecctx_bin *cc = (ecctx_bin *)c; - mp *dx, *dy, *dz, *u, *v; - - dy = F_SQR(f, MP_NEW, a->z); /* %$z^2$% */ - dx = F_MUL(f, MP_NEW, dy, cc->bb); /* %$c z^2$% */ - dx = F_ADD(f, dx, dx, a->x); /* %$x + c z^2$% */ - dz = F_SQR(f, MP_NEW, dx); /* %$(x + c z^2)^2$% */ - dx = F_SQR(f, dx, dz); /* %$x' = (x + c z^2)^4$% */ - - dz = F_MUL(f, dz, dy, a->x); /* %$z' = x z^2$% */ - - dy = F_SQR(f, dy, a->x); /* %$x^2$% */ - u = F_MUL(f, MP_NEW, a->y, a->z); /* %$y z$% */ - u = F_ADD(f, u, u, dz); /* %$z' + y z$% */ - u = F_ADD(f, u, u, dy); /* %$u = z' + x^2 + y z$% */ - - v = F_SQR(f, MP_NEW, dy); /* %$x^4$% */ - dy = F_MUL(f, dy, v, dz); /* %$x^4 z'$% */ - v = F_MUL(f, v, u, dx); /* %$u x'$% */ - dy = F_ADD(f, dy, dy, v); /* %$y' = x^4 z' + u x'$% */ - - EC_DESTROY(d); - d->x = dx; - d->y = dy; - d->z = dz; - MP_DROP(u); - MP_DROP(v); - } - return (d); -} - -static ec *ecadd(ec_curve *c, ec *d, const ec *a, const ec *b) -{ - if (a == b) - ecdbl(c, d, a); - else if (EC_ATINF(a)) - EC_COPY(d, b); - else if (EC_ATINF(b)) - EC_COPY(d, a); - else { - field *f = c->f; - mp *lambda; - mp *dx, *dy; - - if (!MP_EQ(a->x, b->x)) { - dx = F_ADD(f, MP_NEW, a->x, b->x); /* %$x_0 + x_1$% */ - dy = F_INV(f, MP_NEW, dx); /* %$(x_0 + x_1)^{-1}$% */ - dx = F_ADD(f, dx, a->y, b->y); /* %$y_0 + y_1$% */ - lambda = F_MUL(f, MP_NEW, dy, dx); - /* %$\lambda = (y_0 + y_1)/(x_0 + x_1)$% */ - - dx = F_SQR(f, dx, lambda); /* %$\lambda^2$% */ - dx = F_ADD(f, dx, dx, lambda); /* %$\lambda^2 + \lambda$% */ - dx = F_ADD(f, dx, dx, c->a); /* %$a + \lambda^2 + \lambda$% */ - dx = F_ADD(f, dx, dx, a->x); /* %$a + \lambda^2 + \lambda + x_0$% */ - dx = F_ADD(f, dx, dx, b->x); - /* %$x' = a + \lambda^2 + \lambda + x_0 + x_1$% */ - } else if (!MP_EQ(a->y, b->y) || F_ZEROP(f, a->x)) { - EC_SETINF(d); - return (d); - } else { - dx = F_INV(f, MP_NEW, a->x); /* %$x^{-1}$% */ - dy = F_MUL(f, MP_NEW, dx, a->y); /* %$y/x$% */ - lambda = F_ADD(f, dy, dy, a->x); /* %$\lambda = x + y/x$% */ - - dx = F_SQR(f, dx, lambda); /* %$\lambda^2$% */ - dx = F_ADD(f, dx, dx, lambda); /* %$\lambda^2 + \lambda$% */ - dx = F_ADD(f, dx, dx, c->a); /* %$x' = a + \lambda^2 + \lambda$% */ - dy = MP_NEW; - } - - dy = F_ADD(f, dy, a->x, dx); /* %$ x + x' $% */ - dy = F_MUL(f, dy, dy, lambda); /* %$ (x + x') \lambda$% */ - dy = F_ADD(f, dy, dy, a->y); /* %$ (x + x') \lambda + y$% */ - dy = F_ADD(f, dy, dy, dx); /* %$ y' = (x + x') \lambda + y + x'$% */ - - EC_DESTROY(d); - d->x = dx; - d->y = dy; - d->z = 0; - MP_DROP(lambda); - } - return (d); -} - -static ec *ecprojadd(ec_curve *c, ec *d, const ec *a, const ec *b) -{ - if (a == b) - c->ops->dbl(c, d, a); - else if (EC_ATINF(a)) - EC_COPY(d, b); - else if (EC_ATINF(b)) - EC_COPY(d, a); - else { - field *f = c->f; - mp *dx, *dy, *dz, *u, *uu, *v, *t, *s, *ss, *r, *w, *l; - - dz = F_SQR(f, MP_NEW, b->z); /* %$z_1^2$% */ - u = F_MUL(f, MP_NEW, dz, a->x); /* %$u_0 = x_0 z_1^2$% */ - t = F_MUL(f, MP_NEW, dz, b->z); /* %$z_1^3$% */ - s = F_MUL(f, MP_NEW, t, a->y); /* %$s_0 = y_0 z_1^3$% */ - - dz = F_SQR(f, dz, a->z); /* %$z_0^2$% */ - uu = F_MUL(f, MP_NEW, dz, b->x); /* %$u_1 = x_1 z_0^2$% */ - t = F_MUL(f, t, dz, a->z); /* %$z_0^3$% */ - ss = F_MUL(f, MP_NEW, t, b->y); /* %$s_1 = y_1 z_0^3$% */ - - w = F_ADD(f, u, u, uu); /* %$r = u_0 + u_1$% */ - r = F_ADD(f, s, s, ss); /* %$w = s_0 + s_1$% */ - if (F_ZEROP(f, w)) { - MP_DROP(w); - MP_DROP(uu); - MP_DROP(ss); - MP_DROP(t); - MP_DROP(dz); - if (F_ZEROP(f, r)) { - MP_DROP(r); - return (c->ops->dbl(c, d, a)); - } else { - MP_DROP(r); - EC_SETINF(d); - return (d); - } - } - - l = F_MUL(f, t, a->z, w); /* %$l = z_0 w$% */ - - dz = F_MUL(f, dz, l, b->z); /* %$z' = l z_1$% */ - - ss = F_MUL(f, ss, r, b->x); /* %$r x_1$% */ - t = F_MUL(f, uu, l, b->y); /* %$l y_1$% */ - v = F_ADD(f, ss, ss, t); /* %$v = r x_1 + l y_1$% */ - - t = F_ADD(f, t, r, dz); /* %$t = r + z'$% */ - - uu = F_SQR(f, MP_NEW, dz); /* %$z'^2$% */ - dx = F_MUL(f, MP_NEW, uu, c->a); /* %$a z'^2$% */ - uu = F_MUL(f, uu, t, r); /* %$t r$% */ - dx = F_ADD(f, dx, dx, uu); /* %$a z'^2 + t r$% */ - r = F_SQR(f, r, w); /* %$w^2$% */ - uu = F_MUL(f, uu, r, w); /* %$w^3$% */ - dx = F_ADD(f, dx, dx, uu); /* %$x' = a z'^2 + t r + w^3$% */ - - r = F_SQR(f, r, l); /* %$l^2$% */ - dy = F_MUL(f, uu, v, r); /* %$v l^2$% */ - l = F_MUL(f, l, t, dx); /* %$t x'$% */ - dy = F_ADD(f, dy, dy, l); /* %$y' = t x' + v l^2$% */ - - EC_DESTROY(d); - d->x = dx; - d->y = dy; - d->z = dz; - MP_DROP(l); - MP_DROP(r); - MP_DROP(w); - MP_DROP(t); - MP_DROP(v); - } - return (d); -} - -static int eccheck(ec_curve *c, const ec *p) -{ - field *f = c->f; - int rc; - mp *u, *v; - - if (EC_ATINF(p)) return (0); - v = F_SQR(f, MP_NEW, p->x); - u = F_MUL(f, MP_NEW, v, p->x); - v = F_MUL(f, v, v, c->a); - u = F_ADD(f, u, u, v); - u = F_ADD(f, u, u, c->b); - v = F_MUL(f, v, p->x, p->y); - u = F_ADD(f, u, u, v); - v = F_SQR(f, v, p->y); - u = F_ADD(f, u, u, v); - rc = F_ZEROP(f, u) ? 0 : -1; - mp_drop(u); - mp_drop(v); - return (rc); -} - -static int ecprojcheck(ec_curve *c, const ec *p) -{ - ec t = EC_INIT; - int rc; - - c->ops->fix(c, &t, p); - rc = eccheck(c, &t); - EC_DESTROY(&t); - return (rc); -} - -static void ecdestroy(ec_curve *c) -{ - ecctx_bin *cc = (ecctx_bin *)c; - MP_DROP(cc->c.a); - MP_DROP(cc->c.b); - if (cc->bb) MP_DROP(cc->bb); - DESTROY(cc); -} - -/* --- @ec_bin@, @ec_binproj@ --- * - * - * Arguments: @field *f@ = the underlying field for this elliptic curve - * @mp *a, *b@ = the coefficients for this curve - * - * Returns: A pointer to the curve, or null. - * - * Use: Creates a curve structure for an elliptic curve defined over - * a binary field. The @binproj@ variant uses projective - * coordinates, which can be a win. - */ - -ec_curve *ec_bin(field *f, mp *a, mp *b) -{ - ecctx_bin *cc = CREATE(ecctx_bin); - cc->c.ops = &ec_binops; - cc->c.f = f; - cc->c.a = F_IN(f, MP_NEW, a); - cc->c.b = F_IN(f, MP_NEW, b); - cc->bb = 0; - return (&cc->c); -} - -ec_curve *ec_binproj(field *f, mp *a, mp *b) -{ - ecctx_bin *cc = CREATE(ecctx_bin); - int i; - mp *c, *d; - - cc->c.ops = &ec_binprojops; - cc->c.f = f; - cc->c.a = F_IN(f, MP_NEW, a); - cc->c.b = F_IN(f, MP_NEW, b); - - c = MP_COPY(cc->c.b); - for (i = 0; i < f->nbits - 2; i++) - c = F_SQR(f, c, c); - d = F_SQR(f, MP_NEW, c); d = F_SQR(f, d, d); - if (!MP_EQ(d, cc->c.b)) { - MP_DROP(c); - MP_DROP(d); - MP_DROP(cc->c.a); - MP_DROP(cc->c.b); - DESTROY(cc); - return (0); - } - cc->bb = c; - MP_DROP(d); - return (&cc->c); -} - -static const ec_ops ec_binops = { - "bin", - ecdestroy, ec_stdsamep, ec_idin, ec_idout, ec_idfix, - ecfind, ecneg, ecadd, ec_stdsub, ecdbl, eccheck -}; - -static const ec_ops ec_binprojops = { - "binproj", - ecdestroy, ec_stdsamep, ec_projin, ec_projout, ec_projfix, - ecfind, ecprojneg, ecprojadd, ec_stdsub, ecprojdbl, ecprojcheck -}; - -/*----- Test rig ----------------------------------------------------------*/ - -#ifdef TEST_RIG - -#define MP(x) mp_readstring(MP_NEW, #x, 0, 0) - -int main(int argc, char *argv[]) -{ - field *f; - ec_curve *c; - ec g = EC_INIT, d = EC_INIT; - mp *p, *a, *b, *r, *beta; - int i, n = argc == 1 ? 1 : atoi(argv[1]); - - printf("ec-bin: "); - fflush(stdout); - a = MP(0x7ffffffffffffffffffffffffffffffffffffffff); - b = MP(0x6645f3cacf1638e139c6cd13ef61734fbc9e3d9fb); - p = MP(0x800000000000000000000000000000000000000c9); - beta = MP(0x715169c109c612e390d347c748342bcd3b02a0bef); - r = MP(0x040000000000000000000292fe77e70c12a4234c32); - - f = field_binnorm(p, beta); - c = ec_binproj(f, a, b); - g.x = MP(0x0311103c17167564ace77ccb09c681f886ba54ee8); - g.y = MP(0x333ac13c6447f2e67613bf7009daf98c87bb50c7f); - - for (i = 0; i < n; i++) { - ec_mul(c, &d, &g, r); - if (EC_ATINF(&d)) { - fprintf(stderr, "zero too early\n"); - return (1); - } - ec_add(c, &d, &d, &g); - if (!EC_ATINF(&d)) { - fprintf(stderr, "didn't reach zero\n"); - MP_EPRINTX("d.x", d.x); - MP_EPRINTX("d.y", d.y); - return (1); - } - ec_destroy(&d); - } - - ec_destroy(&g); - ec_destroycurve(c); - F_DESTROY(f); - MP_DROP(p); MP_DROP(a); MP_DROP(b); MP_DROP(r); MP_DROP(beta); - assert(!mparena_count(&mparena_global)); - printf("ok\n"); - return (0); -} - -#endif - -/*----- That's all, folks -------------------------------------------------*/