diff options
author | Bodo Möller <bodo@openssl.org> | 2005-11-15 21:08:38 +0000 |
---|---|---|
committer | Bodo Möller <bodo@openssl.org> | 2005-11-15 21:08:38 +0000 |
commit | 8dee9f844f8f22e74d00dff43043732ef1e1fe15 (patch) | |
tree | 3c52e9d545290e1acec34e9844e669676ab74529 /crypto/ec/ec2_smpl.c | |
parent | 963ba100125deb539965429f9114166150a5183b (diff) |
deFUDify: don't require OPENSSL_EC_BIN_PT_COMP
Diffstat (limited to 'crypto/ec/ec2_smpl.c')
-rw-r--r-- | crypto/ec/ec2_smpl.c | 102 |
1 files changed, 84 insertions, 18 deletions
diff --git a/crypto/ec/ec2_smpl.c b/crypto/ec/ec2_smpl.c index a9f7c9d378..a2eb64859f 100644 --- a/crypto/ec/ec2_smpl.c +++ b/crypto/ec/ec2_smpl.c @@ -14,7 +14,7 @@ * */ /* ==================================================================== - * Copyright (c) 1998-2003 The OpenSSL Project. All rights reserved. + * Copyright (c) 1998-2005 The OpenSSL Project. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -403,18 +403,94 @@ int ec_GF2m_simple_point_get_affine_coordinates(const EC_GROUP *group, const EC_ } -/* Include patented algorithms. */ -#include "ec2_smpt.c" +/* Calculates and sets the affine coordinates of an EC_POINT from the given + * compressed coordinates. Uses algorithm 2.3.4 of SEC 1. + * Note that the simple implementation only uses affine coordinates. + * + * The method is from the following publication: + * + * Harper, Menezes, Vanstone: + * "Public-Key Cryptosystems with Very Small Key Lengths", + * EUROCRYPT '92, Springer-Verlag LNCS 658, + * published February 1993 + * + * US Patents 6,141,420 and 6,618,483 (Vanstone, Mullin, Agnew) describe + * the same method, but claim no priority date earlier than July 29, 1994 + * (and additionally fail to cite the EUROCRYPT '92 publication as prior art). + */ +int ec_GF2m_simple_set_compressed_coordinates(const EC_GROUP *group, EC_POINT *point, + const BIGNUM *x_, int y_bit, BN_CTX *ctx) + { + BN_CTX *new_ctx = NULL; + BIGNUM *tmp, *x, *y, *z; + int ret = 0, z0; + + /* clear error queue */ + ERR_clear_error(); + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return 0; + } + + y_bit = (y_bit != 0) ? 1 : 0; + + BN_CTX_start(ctx); + tmp = BN_CTX_get(ctx); + x = BN_CTX_get(ctx); + y = BN_CTX_get(ctx); + z = BN_CTX_get(ctx); + if (z == NULL) goto err; + + if (!BN_GF2m_mod_arr(x, x_, group->poly)) goto err; + if (BN_is_zero(x)) + { + if (!BN_GF2m_mod_sqrt_arr(y, &group->b, group->poly, ctx)) goto err; + } + else + { + if (!group->meth->field_sqr(group, tmp, x, ctx)) goto err; + if (!group->meth->field_div(group, tmp, &group->b, tmp, ctx)) goto err; + if (!BN_GF2m_add(tmp, &group->a, tmp)) goto err; + if (!BN_GF2m_add(tmp, x, tmp)) goto err; + if (!BN_GF2m_mod_solve_quad_arr(z, tmp, group->poly, ctx)) + { + unsigned long err = ERR_peek_last_error(); + + if (ERR_GET_LIB(err) == ERR_LIB_BN && ERR_GET_REASON(err) == BN_R_NO_SOLUTION) + { + ERR_clear_error(); + ECerr(EC_F_EC_GF2M_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSED_POINT); + } + else + ECerr(EC_F_EC_GF2M_SIMPLE_SET_COMPRESSED_COORDINATES, ERR_R_BN_LIB); + goto err; + } + z0 = (BN_is_odd(z)) ? 1 : 0; + if (!group->meth->field_mul(group, y, x, z, ctx)) goto err; + if (z0 != y_bit) + { + if (!BN_GF2m_add(y, y, x)) goto err; + } + } + + if (!EC_POINT_set_affine_coordinates_GF2m(group, point, x, y, ctx)) goto err; + + ret = 1; + + err: + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return ret; + } /* Converts an EC_POINT to an octet string. * If buf is NULL, the encoded length will be returned. * If the length len of buf is smaller than required an error will be returned. - * - * The point compression section of this function is patented by Certicom Corp. - * under US Patent 6,141,420. Point compression is disabled by default and can - * be enabled by defining the preprocessor macro OPENSSL_EC_BIN_PT_COMP at - * Configure-time. */ size_t ec_GF2m_simple_point2oct(const EC_GROUP *group, const EC_POINT *point, point_conversion_form_t form, unsigned char *buf, size_t len, BN_CTX *ctx) @@ -425,14 +501,6 @@ size_t ec_GF2m_simple_point2oct(const EC_GROUP *group, const EC_POINT *point, po BIGNUM *x, *y, *yxi; size_t field_len, i, skip; -#ifndef OPENSSL_EC_BIN_PT_COMP - if ((form == POINT_CONVERSION_COMPRESSED) || (form == POINT_CONVERSION_HYBRID)) - { - ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_DISABLED); - goto err; - } -#endif - if ((form != POINT_CONVERSION_COMPRESSED) && (form != POINT_CONVERSION_UNCOMPRESSED) && (form != POINT_CONVERSION_HYBRID)) @@ -487,13 +555,11 @@ size_t ec_GF2m_simple_point2oct(const EC_GROUP *group, const EC_POINT *point, po if (!EC_POINT_get_affine_coordinates_GF2m(group, point, x, y, ctx)) goto err; buf[0] = form; -#ifdef OPENSSL_EC_BIN_PT_COMP if ((form != POINT_CONVERSION_UNCOMPRESSED) && !BN_is_zero(x)) { if (!group->meth->field_div(group, yxi, y, x, ctx)) goto err; if (BN_is_odd(yxi)) buf[0]++; } -#endif i = 1; |