From 84b08eee4b37c6594e43568f637d3aacbfd6105a Mon Sep 17 00:00:00 2001 From: "Dr. Stephen Henson" Date: Mon, 14 Feb 2011 16:52:12 +0000 Subject: Reorganise ECC code for inclusion in FIPS module. Move compression, point2oct and oct2point functions into separate files. Add a flags field to EC_METHOD. Add a flag EC_FLAGS_DEFAULT_OCT to use the default compession and oct functions (all existing methods do this). This removes dependencies from EC_METHOD while keeping original functionality. --- crypto/ec/ec2_smpl.c | 341 +-------------------------------------------------- 1 file changed, 4 insertions(+), 337 deletions(-) (limited to 'crypto/ec/ec2_smpl.c') diff --git a/crypto/ec/ec2_smpl.c b/crypto/ec/ec2_smpl.c index a379c9b450..f37347b5e1 100644 --- a/crypto/ec/ec2_smpl.c +++ b/crypto/ec/ec2_smpl.c @@ -67,6 +67,8 @@ * */ +#define OPENSSL_FIPSAPI + #include #include "ec_lcl.h" @@ -77,6 +79,7 @@ const EC_METHOD *EC_GF2m_simple_method(void) { static const EC_METHOD ret = { + EC_FLAGS_DEFAULT_OCT, NID_X9_62_characteristic_two_field, ec_GF2m_simple_group_init, ec_GF2m_simple_group_finish, @@ -95,9 +98,7 @@ const EC_METHOD *EC_GF2m_simple_method(void) 0 /* get_Jprojective_coordinates_GFp */, ec_GF2m_simple_point_set_affine_coordinates, ec_GF2m_simple_point_get_affine_coordinates, - ec_GF2m_simple_set_compressed_coordinates, - ec_GF2m_simple_point2oct, - ec_GF2m_simple_oct2point, + 0,0,0, ec_GF2m_simple_add, ec_GF2m_simple_dbl, ec_GF2m_simple_invert, @@ -407,340 +408,6 @@ int ec_GF2m_simple_point_get_affine_coordinates(const EC_GROUP *group, const EC_ return ret; } - -/* 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. - */ -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) - { - size_t ret; - BN_CTX *new_ctx = NULL; - int used_ctx = 0; - BIGNUM *x, *y, *yxi; - size_t field_len, i, skip; - - if ((form != POINT_CONVERSION_COMPRESSED) - && (form != POINT_CONVERSION_UNCOMPRESSED) - && (form != POINT_CONVERSION_HYBRID)) - { - ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, EC_R_INVALID_FORM); - goto err; - } - - if (EC_POINT_is_at_infinity(group, point)) - { - /* encodes to a single 0 octet */ - if (buf != NULL) - { - if (len < 1) - { - ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL); - return 0; - } - buf[0] = 0; - } - return 1; - } - - - /* ret := required output buffer length */ - field_len = (EC_GROUP_get_degree(group) + 7) / 8; - ret = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2*field_len; - - /* if 'buf' is NULL, just return required length */ - if (buf != NULL) - { - if (len < ret) - { - ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL); - goto err; - } - - if (ctx == NULL) - { - ctx = new_ctx = BN_CTX_new(); - if (ctx == NULL) - return 0; - } - - BN_CTX_start(ctx); - used_ctx = 1; - x = BN_CTX_get(ctx); - y = BN_CTX_get(ctx); - yxi = BN_CTX_get(ctx); - if (yxi == NULL) goto err; - - if (!EC_POINT_get_affine_coordinates_GF2m(group, point, x, y, ctx)) goto err; - - buf[0] = form; - 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]++; - } - - i = 1; - - skip = field_len - BN_num_bytes(x); - if (skip > field_len) - { - ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR); - goto err; - } - while (skip > 0) - { - buf[i++] = 0; - skip--; - } - skip = BN_bn2bin(x, buf + i); - i += skip; - if (i != 1 + field_len) - { - ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR); - goto err; - } - - if (form == POINT_CONVERSION_UNCOMPRESSED || form == POINT_CONVERSION_HYBRID) - { - skip = field_len - BN_num_bytes(y); - if (skip > field_len) - { - ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR); - goto err; - } - while (skip > 0) - { - buf[i++] = 0; - skip--; - } - skip = BN_bn2bin(y, buf + i); - i += skip; - } - - if (i != ret) - { - ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR); - goto err; - } - } - - if (used_ctx) - BN_CTX_end(ctx); - if (new_ctx != NULL) - BN_CTX_free(new_ctx); - return ret; - - err: - if (used_ctx) - BN_CTX_end(ctx); - if (new_ctx != NULL) - BN_CTX_free(new_ctx); - return 0; - } - - -/* Converts an octet string representation to an EC_POINT. - * Note that the simple implementation only uses affine coordinates. - */ -int ec_GF2m_simple_oct2point(const EC_GROUP *group, EC_POINT *point, - const unsigned char *buf, size_t len, BN_CTX *ctx) - { - point_conversion_form_t form; - int y_bit; - BN_CTX *new_ctx = NULL; - BIGNUM *x, *y, *yxi; - size_t field_len, enc_len; - int ret = 0; - - if (len == 0) - { - ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_BUFFER_TOO_SMALL); - return 0; - } - form = buf[0]; - y_bit = form & 1; - form = form & ~1U; - if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED) - && (form != POINT_CONVERSION_UNCOMPRESSED) - && (form != POINT_CONVERSION_HYBRID)) - { - ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); - return 0; - } - if ((form == 0 || form == POINT_CONVERSION_UNCOMPRESSED) && y_bit) - { - ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); - return 0; - } - - if (form == 0) - { - if (len != 1) - { - ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); - return 0; - } - - return EC_POINT_set_to_infinity(group, point); - } - - field_len = (EC_GROUP_get_degree(group) + 7) / 8; - enc_len = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2*field_len; - - if (len != enc_len) - { - ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); - return 0; - } - - if (ctx == NULL) - { - ctx = new_ctx = BN_CTX_new(); - if (ctx == NULL) - return 0; - } - - BN_CTX_start(ctx); - x = BN_CTX_get(ctx); - y = BN_CTX_get(ctx); - yxi = BN_CTX_get(ctx); - if (yxi == NULL) goto err; - - if (!BN_bin2bn(buf + 1, field_len, x)) goto err; - if (BN_ucmp(x, &group->field) >= 0) - { - ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); - goto err; - } - - if (form == POINT_CONVERSION_COMPRESSED) - { - if (!EC_POINT_set_compressed_coordinates_GF2m(group, point, x, y_bit, ctx)) goto err; - } - else - { - if (!BN_bin2bn(buf + 1 + field_len, field_len, y)) goto err; - if (BN_ucmp(y, &group->field) >= 0) - { - ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); - goto err; - } - if (form == POINT_CONVERSION_HYBRID) - { - if (!group->meth->field_div(group, yxi, y, x, ctx)) goto err; - if (y_bit != BN_is_odd(yxi)) - { - ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); - goto err; - } - } - - if (!EC_POINT_set_affine_coordinates_GF2m(group, point, x, y, ctx)) goto err; - } - - if (!EC_POINT_is_on_curve(group, point, ctx)) /* test required by X9.62 */ - { - ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_POINT_IS_NOT_ON_CURVE); - goto err; - } - - ret = 1; - - err: - BN_CTX_end(ctx); - if (new_ctx != NULL) - BN_CTX_free(new_ctx); - return ret; - } - - /* Computes a + b and stores the result in r. r could be a or b, a could be b. * Uses algorithm A.10.2 of IEEE P1363. */ -- cgit v1.2.3