More method functions.

diff --git a/crypto/ec/ec.h b/crypto/ec/ec.h
index cc0dd788bd7b87e4adef39432633b5447d75db60..93fde52ffa4c06596ba846151cb411fa2a71917f 100644 (file)
--- a/crypto/ec/ec.h
+++ b/crypto/ec/ec.h
@@ -133,7 +133,7 @@ int EC_POINT_dbl(const EC_GROUP *, EC_POINT *r, const EC_POINT *a, BN_CTX *);
 int EC_POINT_is_at_infinity(const EC_GROUP *, const EC_POINT *);
 int EC_POINT_is_on_curve(const EC_GROUP *, const EC_POINT *, BN_CTX *);
 
-int EC_POINT_make_affine(const EC_GROUP *, const EC_POINT *, BN_CTX *);
+int EC_POINT_make_affine(const EC_GROUP *, EC_POINT *, BN_CTX *);
 
 
 
@@ -150,6 +150,7 @@ int EC_POINT_make_affine(const EC_GROUP *, const EC_POINT *, BN_CTX *);
 
 /* Function codes. */
 #define EC_F_EC_GFP_SIMPLE_GROUP_SET_GENERATOR          117
+#define EC_F_EC_GFP_SIMPLE_MAKE_AFFINE                  118
 #define EC_F_EC_GROUP_CLEAR_FREE                        103
 #define EC_F_EC_GROUP_COPY                              102
 #define EC_F_EC_GROUP_FREE                              104

diff --git a/crypto/ec/ec_err.c b/crypto/ec/ec_err.c
index 770bce537371b9c410bd7e5fe9ebe3d36b38a137..cd2d79267a5fe0c2f7803937be3e02fc4eb50d42 100644 (file)
--- a/crypto/ec/ec_err.c
+++ b/crypto/ec/ec_err.c
@@ -67,6 +67,7 @@
 static ERR_STRING_DATA EC_str_functs[]=
        {
 {ERR_PACK(0,EC_F_EC_GFP_SIMPLE_GROUP_SET_GENERATOR,0), "EC_GFP_SIMPLE_GROUP_SET_GENERATOR"},
+{ERR_PACK(0,EC_F_EC_GFP_SIMPLE_MAKE_AFFINE,0), "EC_GFP_SIMPLE_MAKE_AFFINE"},
 {ERR_PACK(0,EC_F_EC_GROUP_CLEAR_FREE,0),       "EC_GROUP_clear_free"},
 {ERR_PACK(0,EC_F_EC_GROUP_COPY,0),     "EC_GROUP_copy"},
 {ERR_PACK(0,EC_F_EC_GROUP_FREE,0),     "EC_GROUP_free"},

diff --git a/crypto/ec/ec_lcl.h b/crypto/ec/ec_lcl.h
index 231e8ca17948e8d7c0d9f89d5058601578ef9f55..4bfcc916fd2c822948da99f9a366d037d328bfd9 100644 (file)
--- a/crypto/ec/ec_lcl.h
+++ b/crypto/ec/ec_lcl.h
@@ -99,7 +99,7 @@ struct ec_method_st {
        /* used by EC_POINT_is_at_infinity, EC_POINT_is_on_curve, EC_POINT_make_affine */
        int (*is_at_infinity)(const EC_GROUP *, const EC_POINT *);
        int (*is_on_curve)(const EC_GROUP *, const EC_POINT *, BN_CTX *);
-       int (*make_affine)(const EC_GROUP *, const EC_POINT *, BN_CTX *);
+       int (*make_affine)(const EC_GROUP *, EC_POINT *, BN_CTX *);
 
 
        /* internal functions */
@@ -134,7 +134,7 @@ struct ec_group_st {
                      * or abused for all kinds of fields, not just GF(p).)
                      * For characteristic  > 3,  the curve is defined
                      * by a Weierstrass equation of the form
-                     *     Y^2 = X^3 + a*X + b.
+                     *     y^2 = x^3 + a*x + b.
                      */
        int a_is_minus3; /* enable optimized point arithmetics for special case */
 
@@ -197,7 +197,7 @@ int ec_GFp_simple_add(const EC_GROUP *, EC_POINT *r, const EC_POINT *a, const EC
 int ec_GFp_simple_dbl(const EC_GROUP *, EC_POINT *r, const EC_POINT *a, BN_CTX *);
 int ec_GFp_simple_is_at_infinity(const EC_GROUP *, const EC_POINT *);
 int ec_GFp_simple_is_on_curve(const EC_GROUP *, const EC_POINT *, BN_CTX *);
-int ec_GFp_simple_make_affine(const EC_GROUP *, const EC_POINT *, BN_CTX *);
+int ec_GFp_simple_make_affine(const EC_GROUP *, EC_POINT *, BN_CTX *);
 int ec_GFp_simple_field_mul(const EC_GROUP *, BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *);
 int ec_GFp_simple_field_sqr(const EC_GROUP *, BIGNUM *r, const BIGNUM *a, BN_CTX *);
 

diff --git a/crypto/ec/ec_lib.c b/crypto/ec/ec_lib.c
index 2056d58cd35546ea0b4adc4191b0f71de608f585..90da84eb7d0041a8b9aa58729a5eee13d4024477 100644 (file)
--- a/crypto/ec/ec_lib.c
+++ b/crypto/ec/ec_lib.c
@@ -421,7 +421,7 @@ int EC_POINT_is_on_curve(const EC_GROUP *group, const EC_POINT *point, BN_CTX *c
        }
 
 
-int EC_POINT_make_affine(const EC_GROUP *group, const EC_POINT *point, BN_CTX *ctx)
+int EC_POINT_make_affine(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx)
        {
        if (group->meth->make_affine == 0)
                {

diff --git a/crypto/ec/ecp_smpl.c b/crypto/ec/ecp_smpl.c
index bae752841a5dbc0427034df9a5f0360837fe2126..5306efdf157beaae1e10ed91ae8a4d693de32069 100644 (file)
--- a/crypto/ec/ecp_smpl.c
+++ b/crypto/ec/ecp_smpl.c
@@ -385,8 +385,8 @@ int ec_GFp_simple_add(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, con
                        {
                        /* a is the same point as b */
                        BN_CTX_end(ctx);
-                       ctx = NULL;
                        ret = EC_POINT_dbl(group, r, a, ctx);
+                       ctx = NULL;
                        goto end;
                        }
                else
@@ -491,8 +491,6 @@ int ec_GFp_simple_dbl(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, BN_
        n3 = BN_CTX_get(ctx);
        if (n3 == NULL) goto err;
 
-       /* TODO: optimization for group->a_is_minus3 */
-
        /* n1 */
        if (a->Z_is_one)
                {
@@ -577,12 +575,168 @@ int ec_GFp_simple_is_at_infinity(const EC_GROUP *group, const EC_POINT *point)
        }
 
 
-int ec_GFp_simple_is_on_curve(const EC_GROUP *group, const EC_POINT *point, BN_CTX *ctx);
-/* TODO */
+int ec_GFp_simple_is_on_curve(const EC_GROUP *group, const EC_POINT *point, BN_CTX *ctx)
+       {
+       int (*field_mul)(const EC_GROUP *, BIGNUM *, const BIGNUM *, const BIGNUM *, BN_CTX *);
+       int (*field_sqr)(const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *);
+       const BIGNUM *p;
+       BN_CTX *new_ctx = NULL;
+       BIGNUM *rh, *tmp1, *tmp2, *Z4, *Z6;
+       int ret = -1;
 
+       if (EC_POINT_is_at_infinity(group, point))
+               return 1;
+       
+       field_mul = group->meth->field_mul;
+       field_sqr = group->meth->field_sqr;
+       p = &group->field;
 
-int ec_GFp_simple_make_affine(const EC_GROUP *group, const EC_POINT *point, BN_CTX *ctx);
-/* TODO */
+       if (ctx == NULL)
+               {
+               ctx = new_ctx = BN_CTX_new();
+               if (ctx == NULL)
+                       return 0;
+               }
+       BN_CTX_start(ctx);
+
+       rh = BN_CTX_get(ctx);
+       tmp1 = BN_CTX_get(ctx);
+       tmp2 = BN_CTX_get(ctx);
+       Z4 = BN_CTX_get(ctx);
+       Z6 = BN_CTX_get(ctx);
+       if (Z6 == NULL) goto err;
+
+       /* We have a curve defined by a Weierstrass equation
+        *      y^2 = x^3 + a*x + b.
+        * The point to consider is given in Jacobian projective coordinates
+        * where  (X, Y, Z)  represents  (x, y) = (X/Z^2, Y/Z^3).
+        * Substituting this and multiplying by  Z^6  transforms the above equation into
+        *      Y^2 = X^3 + a*X*Z^4 + b*Z^6.
+        * To test this, we add up the right-hand side in 'rh'.
+        */
+
+       /* rh := X^3 */
+       if (!field_sqr(group, rh, &point->X, ctx)) goto err;
+       if (!field_mul(group, rh, rh, &point->X, ctx)) goto err;
+
+       if (!point->Z_is_one)
+               {
+               if (!field_sqr(group, tmp1, &point->Z, ctx)) goto err;
+               if (!field_sqr(group, Z4, tmp1, ctx)) goto err;
+               if (!field_mul(group, Z6, Z4, tmp1, ctx)) goto err;
+
+               /* rh := rh + a*X*Z^4 */
+               if (!field_mul(group, tmp1, &point->X, Z4, ctx)) goto err;
+               if (&group->a_is_minus3)
+                       {
+                       if (!BN_mod_lshift1_quick(tmp2, tmp1, p)) goto err;
+                       if (!BN_mod_add_quick(tmp2, tmp2, tmp1, p)) goto err;
+                       if (!BN_mod_sub_quick(rh, rh, tmp2, p)) goto err;
+                       }
+               else
+                       {
+                       if (!field_mul(group, tmp2, tmp1, &group->a, ctx)) goto err;
+                       if (!BN_mod_add_quick(rh, rh, tmp2, p)) goto err;
+                       }
+
+               /* rh := rh + b*Z^6 */
+               if (!field_mul(group, tmp1, &group->b, Z6, ctx)) goto err;
+               if (!BN_mod_add_quick(rh, rh, tmp1, p)) goto err;
+               }
+       else
+               {
+               /* point->Z_is_one */
+
+               /* rh := rh + a*X */
+               if (&group->a_is_minus3)
+                       {
+                       if (!BN_mod_lshift1_quick(tmp2, &point->X, p)) goto err;
+                       if (!BN_mod_add_quick(tmp2, tmp2, &point->X, p)) goto err;
+                       if (!BN_mod_sub_quick(rh, rh, tmp2, p)) goto err;
+                       }
+               else
+                       {
+                       if (!field_mul(group, tmp2, &point->X, &group->a, ctx)) goto err;
+                       if (!BN_mod_add_quick(rh, rh, tmp2, p)) goto err;
+                       }
+
+               /* rh := rh + b */
+               if (!BN_mod_add_quick(rh, rh, &group->b, p)) goto err;
+               }
+
+       /* 'lh' := Y^2 */
+       if (!field_sqr(group, tmp1, &point->Y, ctx)) goto err;
+
+       ret = (0 == BN_cmp(tmp1, rh));
+
+ err:
+       BN_CTX_end(ctx);
+       if (new_ctx != NULL)
+               BN_CTX_free(new_ctx);
+       return ret;
+       }
+
+
+int ec_GFp_simple_make_affine(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx)
+       {
+       BN_CTX *new_ctx = NULL;
+       BIGNUM *Z, *Z_1, *Z_2, *Z_3;
+       int ret = 0;
+
+       if (point->Z_is_one || EC_POINT_is_at_infinity(group, point))
+               return 1;
+
+       if (ctx == NULL)
+               {
+               ctx = new_ctx = BN_CTX_new();
+               if (ctx == NULL)
+                       return 0;
+               }
+       BN_CTX_start(ctx);
+
+       Z = BN_CTX_get(ctx);
+       Z_1 = BN_CTX_get(ctx);
+       Z_2 = BN_CTX_get(ctx);
+       Z_3 = BN_CTX_get(ctx);
+       if (Z_3 == NULL) goto end;
+
+       /* transform  (X, Y, Z)  into  (X/Z^2, Y/Z^3, 1) */
+       
+       if (group->meth->field_decode)
+               {
+               if (!group->meth->field_decode(group, Z, &point->Z, ctx)) goto end;
+               }
+       else
+               Z = &point->Z;
+       
+       if (BN_is_one(Z))
+               {
+               point->Z_is_one = 1;
+               ret = 1;
+               goto end;
+               }
+
+       if (!BN_mod_inverse(Z_1, Z, &group->field, ctx))
+               {
+               ECerr(EC_F_EC_GFP_SIMPLE_MAKE_AFFINE, ERR_R_BN_LIB);
+               goto end;
+               }
+       if (!BN_mod_sqr(Z_2, Z_1, &group->field, ctx)) goto end;
+       if (!BN_mod_mul(Z_3, Z_2, Z_1, &group->field, ctx)) goto end;
+       
+       if (!BN_mod_mul(&point->X, &point->X, Z_2, &group->field, ctx)) goto end;
+       if (!BN_mod_mul(&point->Y, &point->Y, Z_2, &group->field, ctx)) goto end;
+       if (!BN_set_word(&point->Z, 1)) goto end;
+       point->Z_is_one = 1;
+
+       ret = 1;
+
+ end:
+       BN_CTX_end(ctx);
+       if (new_ctx != NULL)
+               BN_CTX_free(new_ctx);
+       return ret;
+       }
 
 
 int ec_GFp_simple_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)