SCA hardening for mod. field inversion in EC_GROUP

[openssl.git] / crypto / ec / ec_lcl.h

diff --git a/crypto/ec/ec_lcl.h b/crypto/ec/ec_lcl.h
index 3153e4fa0d0cb31f632419536547dedd9f3d5cf6..312b538991e9f1dd0b6424c67615f34ac79f66f2 100644 (file)
--- a/crypto/ec/ec_lcl.h
+++ b/crypto/ec/ec_lcl.h
@@ -154,6 +154,13 @@ struct ec_method_st {
     int (*field_sqr) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a, BN_CTX *);
     int (*field_div) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
                       const BIGNUM *b, BN_CTX *);
+    /*-
+     * 'field_inv' computes the multipicative inverse of a in the field,
+     * storing the result in r.
+     *
+     * If 'a' is zero (or equivalent), you'll get an EC_R_CANNOT_INVERT error.
+     */
+    int (*field_inv) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a, BN_CTX *);
     /* e.g. to Montgomery */
     int (*field_encode) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
                          BN_CTX *);
@@ -390,6 +397,8 @@ 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 *);
+int ec_GFp_simple_field_inv(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
+                            BN_CTX *);
 int ec_GFp_simple_blind_coordinates(const EC_GROUP *group, EC_POINT *p,
                                     BN_CTX *ctx);
 int ec_GFp_simple_ladder_pre(const EC_GROUP *group,
@@ -413,6 +422,8 @@ int ec_GFp_mont_field_mul(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
                           const BIGNUM *b, BN_CTX *);
 int ec_GFp_mont_field_sqr(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
                           BN_CTX *);
+int ec_GFp_mont_field_inv(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
+                          BN_CTX *);
 int ec_GFp_mont_field_encode(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
                              BN_CTX *);
 int ec_GFp_mont_field_decode(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,