X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=crypto%2Fec%2Fec2_smpl.c;h=01d8483c3af1036a3222183854ab7cd9b2332724;hb=ea71ec1b11e585b3cd704af1930c09c0c1606916;hp=d34e97d676d859f64675c25c4c31080d2b13b6ca;hpb=560f7abb7e12d09b5e1dd2e9c8e3c6a04fc901d3;p=oweals%2Fopenssl.git

diff --git a/crypto/ec/ec2_smpl.c b/crypto/ec/ec2_smpl.c
index d34e97d676..01d8483c3a 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
@@ -157,6 +157,7 @@ void ec_GF2m_simple_group_clear_finish(EC_GROUP *group)
 	group->poly[2] = 0;
 	group->poly[3] = 0;
 	group->poly[4] = 0;
+	group->poly[5] = -1;
 	}
 
 
@@ -174,6 +175,7 @@ int ec_GF2m_simple_group_copy(EC_GROUP *dest, const EC_GROUP *src)
 	dest->poly[2] = src->poly[2];
 	dest->poly[3] = src->poly[3];
 	dest->poly[4] = src->poly[4];
+	dest->poly[5] = src->poly[5];
 	bn_wexpand(&dest->a, (int)(dest->poly[0] + BN_BITS2 - 1) / BN_BITS2);
 	bn_wexpand(&dest->b, (int)(dest->poly[0] + BN_BITS2 - 1) / BN_BITS2);
 	for (i = dest->a.top; i < dest->a.dmax; i++) dest->a.d[i] = 0;
@@ -190,7 +192,7 @@ int ec_GF2m_simple_group_set_curve(EC_GROUP *group,
 
 	/* group->field */
 	if (!BN_copy(&group->field, p)) goto err;
-	i = BN_GF2m_poly2arr(&group->field, group->poly, 5);
+	i = BN_GF2m_poly2arr(&group->field, group->poly, 6) - 1;
 	if ((i != 5) && (i != 3))
 		{
 		ECerr(EC_F_EC_GF2M_SIMPLE_GROUP_SET_CURVE, EC_R_UNSUPPORTED_FIELD);
@@ -281,7 +283,8 @@ int ec_GF2m_simple_group_check_discriminant(const EC_GROUP *group, BN_CTX *ctx)
 	ret = 1;
 
 err:
-	BN_CTX_end(ctx);
+	if (ctx != NULL)
+		BN_CTX_end(ctx);
 	if (new_ctx != NULL)
 		BN_CTX_free(new_ctx);
 	return ret;
@@ -354,11 +357,11 @@ int ec_GF2m_simple_point_set_affine_coordinates(const EC_GROUP *group, EC_POINT
 		}
 
 	if (!BN_copy(&point->X, x)) goto err;
-	BN_set_sign(&point->X, 0);
+	BN_set_negative(&point->X, 0);
 	if (!BN_copy(&point->Y, y)) goto err;
-	BN_set_sign(&point->Y, 0);
+	BN_set_negative(&point->Y, 0);
 	if (!BN_copy(&point->Z, BN_value_one())) goto err;
-	BN_set_sign(&point->Z, 0);
+	BN_set_negative(&point->Z, 0);
 	point->Z_is_one = 1;
 	ret = 1;
 
@@ -389,12 +392,12 @@ int ec_GF2m_simple_point_get_affine_coordinates(const EC_GROUP *group, const EC_
 	if (x != NULL)
 		{
 		if (!BN_copy(x, &point->X)) goto err;
-		BN_set_sign(x, 0);
+		BN_set_negative(x, 0);
 		}
 	if (y != NULL)
 		{
 		if (!BN_copy(y, &point->Y)) goto err;
-		BN_set_sign(y, 0);
+		BN_set_negative(y, 0);
 		}
 	ret = 1;
 		
@@ -403,18 +406,94 @@ 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 +504,6 @@ 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 +558,11 @@ 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;
 		
@@ -805,13 +874,18 @@ int ec_GF2m_simple_is_at_infinity(const EC_GROUP *group, const EC_POINT *point)
  */
 int ec_GF2m_simple_is_on_curve(const EC_GROUP *group, const EC_POINT *point, BN_CTX *ctx)
 	{
-	BN_CTX *new_ctx = NULL;
-	BIGNUM *rh, *lh, *tmp1;
 	int ret = -1;
+	BN_CTX *new_ctx = NULL;
+	BIGNUM *lh, *y2;
+	int (*field_mul)(const EC_GROUP *, BIGNUM *, const BIGNUM *, const BIGNUM *, BN_CTX *);
+	int (*field_sqr)(const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *);
 
 	if (EC_POINT_is_at_infinity(group, point))
 		return 1;
-	
+
+	field_mul = group->meth->field_mul;
+	field_sqr = group->meth->field_sqr;	
+
 	/* only support affine coordinates */
 	if (!point->Z_is_one) goto err;
 
@@ -823,37 +897,23 @@ int ec_GF2m_simple_is_on_curve(const EC_GROUP *group, const EC_POINT *point, BN_
 		}
 
 	BN_CTX_start(ctx);
-	rh = BN_CTX_get(ctx);
+	y2 = BN_CTX_get(ctx);
 	lh = BN_CTX_get(ctx);
-	tmp1 = BN_CTX_get(ctx);
-	if (tmp1 == NULL) goto err;
+	if (lh == NULL) goto err;
 
 	/* We have a curve defined by a Weierstrass equation
 	 *      y^2 + x*y = x^3 + a*x^2 + b.
-	 * To test this, we add up the right-hand side in 'rh'
-	 * and the left-hand side in 'lh'.
+	 *  <=> x^3 + a*x^2 + x*y + b + y^2 = 0
+	 *  <=> ((x + a) * x + y ) * x + b + y^2 = 0
 	 */
-
-	/* rh := X^3 */
-	if (!group->meth->field_sqr(group, tmp1, &point->X, ctx)) goto err;
-	if (!group->meth->field_mul(group, rh, tmp1, &point->X, ctx)) goto err;
-
-	/* rh := rh + a*X^2 */
-	if (!group->meth->field_mul(group, tmp1, tmp1, &group->a, ctx)) goto err;
-	if (!BN_GF2m_add(rh, rh, tmp1)) goto err;
-
-	/* rh := rh + b */
-	if (!BN_GF2m_add(rh, rh, &group->b)) goto err;
-
-	/* lh := Y^2 */
-	if (!group->meth->field_sqr(group, lh, &point->Y, ctx)) goto err;
-
-	/* lh := lh + x*y */
-	if (!group->meth->field_mul(group, tmp1, &point->X, &point->Y, ctx)) goto err;
-	if (!BN_GF2m_add(lh, lh, tmp1)) goto err;
-
-	ret = (0 == BN_GF2m_cmp(lh, rh));
-
+	if (!BN_GF2m_add(lh, &point->X, &group->a)) goto err;
+	if (!field_mul(group, lh, lh, &point->X, ctx)) goto err;
+	if (!BN_GF2m_add(lh, lh, &point->Y)) goto err;
+	if (!field_mul(group, lh, lh, &point->X, ctx)) goto err;
+	if (!BN_GF2m_add(lh, lh, &group->b)) goto err;
+	if (!field_sqr(group, y2, &point->Y, ctx)) goto err;
+	if (!BN_GF2m_add(lh, lh, y2)) goto err;
+	ret = BN_is_zero(lh);
  err:
 	if (ctx) BN_CTX_end(ctx);
 	if (new_ctx) BN_CTX_free(new_ctx);