+struct ec_method_st {
+ /* Various method flags */
+ int flags;
+ /* used by EC_METHOD_get_field_type: */
+ int field_type; /* a NID */
+ /*
+ * used by EC_GROUP_new, EC_GROUP_free, EC_GROUP_clear_free,
+ * EC_GROUP_copy:
+ */
+ int (*group_init) (EC_GROUP *);
+ void (*group_finish) (EC_GROUP *);
+ void (*group_clear_finish) (EC_GROUP *);
+ int (*group_copy) (EC_GROUP *, const EC_GROUP *);
+ /* used by EC_GROUP_set_curve, EC_GROUP_get_curve: */
+ int (*group_set_curve) (EC_GROUP *, const BIGNUM *p, const BIGNUM *a,
+ const BIGNUM *b, BN_CTX *);
+ int (*group_get_curve) (const EC_GROUP *, BIGNUM *p, BIGNUM *a, BIGNUM *b,
+ BN_CTX *);
+ /* used by EC_GROUP_get_degree: */
+ int (*group_get_degree) (const EC_GROUP *);
+ int (*group_order_bits) (const EC_GROUP *);
+ /* used by EC_GROUP_check: */
+ int (*group_check_discriminant) (const EC_GROUP *, BN_CTX *);
+ /*
+ * used by EC_POINT_new, EC_POINT_free, EC_POINT_clear_free,
+ * EC_POINT_copy:
+ */
+ int (*point_init) (EC_POINT *);
+ void (*point_finish) (EC_POINT *);
+ void (*point_clear_finish) (EC_POINT *);
+ int (*point_copy) (EC_POINT *, const EC_POINT *);
+ /*-
+ * used by EC_POINT_set_to_infinity,
+ * EC_POINT_set_Jprojective_coordinates_GFp,
+ * EC_POINT_get_Jprojective_coordinates_GFp,
+ * EC_POINT_set_affine_coordinates,
+ * EC_POINT_get_affine_coordinates,
+ * EC_POINT_set_compressed_coordinates:
+ */
+ int (*point_set_to_infinity) (const EC_GROUP *, EC_POINT *);
+ int (*point_set_Jprojective_coordinates_GFp) (const EC_GROUP *,
+ EC_POINT *, const BIGNUM *x,
+ const BIGNUM *y,
+ const BIGNUM *z, BN_CTX *);
+ int (*point_get_Jprojective_coordinates_GFp) (const EC_GROUP *,
+ const EC_POINT *, BIGNUM *x,
+ BIGNUM *y, BIGNUM *z,
+ BN_CTX *);
+ int (*point_set_affine_coordinates) (const EC_GROUP *, EC_POINT *,
+ const BIGNUM *x, const BIGNUM *y,
+ BN_CTX *);
+ int (*point_get_affine_coordinates) (const EC_GROUP *, const EC_POINT *,
+ BIGNUM *x, BIGNUM *y, BN_CTX *);
+ int (*point_set_compressed_coordinates) (const EC_GROUP *, EC_POINT *,
+ const BIGNUM *x, int y_bit,
+ BN_CTX *);
+ /* used by EC_POINT_point2oct, EC_POINT_oct2point: */
+ size_t (*point2oct) (const EC_GROUP *, const EC_POINT *,
+ point_conversion_form_t form, unsigned char *buf,
+ size_t len, BN_CTX *);
+ int (*oct2point) (const EC_GROUP *, EC_POINT *, const unsigned char *buf,
+ size_t len, BN_CTX *);
+ /* used by EC_POINT_add, EC_POINT_dbl, ECP_POINT_invert: */
+ int (*add) (const EC_GROUP *, EC_POINT *r, const EC_POINT *a,
+ const EC_POINT *b, BN_CTX *);
+ int (*dbl) (const EC_GROUP *, EC_POINT *r, const EC_POINT *a, BN_CTX *);
+ int (*invert) (const EC_GROUP *, EC_POINT *, BN_CTX *);
+ /*
+ * used by EC_POINT_is_at_infinity, EC_POINT_is_on_curve, EC_POINT_cmp:
+ */
+ int (*is_at_infinity) (const EC_GROUP *, const EC_POINT *);
+ int (*is_on_curve) (const EC_GROUP *, const EC_POINT *, BN_CTX *);
+ int (*point_cmp) (const EC_GROUP *, const EC_POINT *a, const EC_POINT *b,
+ BN_CTX *);
+ /* used by EC_POINT_make_affine, EC_POINTs_make_affine: */
+ int (*make_affine) (const EC_GROUP *, EC_POINT *, BN_CTX *);
+ int (*points_make_affine) (const EC_GROUP *, size_t num, EC_POINT *[],
+ BN_CTX *);
+ /*
+ * used by EC_POINTs_mul, EC_POINT_mul, EC_POINT_precompute_mult,
+ * EC_POINT_have_precompute_mult (default implementations are used if the
+ * 'mul' pointer is 0):
+ */
+ /*-
+ * mul() calculates the value
+ *
+ * r := generator * scalar
+ * + points[0] * scalars[0]
+ * + ...
+ * + points[num-1] * scalars[num-1].
+ *
+ * For a fixed point multiplication (scalar != NULL, num == 0)
+ * or a variable point multiplication (scalar == NULL, num == 1),
+ * mul() must use a constant time algorithm: in both cases callers
+ * should provide an input scalar (either scalar or scalars[0])
+ * in the range [0, ec_group_order); for robustness, implementers
+ * should handle the case when the scalar has not been reduced, but
+ * may treat it as an unusual input, without any constant-timeness
+ * guarantee.
+ */
+ int (*mul) (const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
+ size_t num, const EC_POINT *points[], const BIGNUM *scalars[],
+ BN_CTX *);
+ int (*precompute_mult) (EC_GROUP *group, BN_CTX *);
+ int (*have_precompute_mult) (const EC_GROUP *group);
+ /* internal functions */
+ /*
+ * 'field_mul', 'field_sqr', and 'field_div' can be used by 'add' and
+ * 'dbl' so that the same implementations of point operations can be used
+ * with different optimized implementations of expensive field
+ * operations:
+ */
+ int (*field_mul) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
+ const BIGNUM *b, BN_CTX *);
+ 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 *);
+ /* e.g. to Montgomery */
+ int (*field_encode) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
+ BN_CTX *);
+ /* e.g. from Montgomery */
+ int (*field_decode) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
+ BN_CTX *);
+ int (*field_set_to_one) (const EC_GROUP *, BIGNUM *r, BN_CTX *);
+ /* private key operations */
+ size_t (*priv2oct)(const EC_KEY *eckey, unsigned char *buf, size_t len);
+ int (*oct2priv)(EC_KEY *eckey, const unsigned char *buf, size_t len);
+ int (*set_private)(EC_KEY *eckey, const BIGNUM *priv_key);
+ int (*keygen)(EC_KEY *eckey);
+ int (*keycheck)(const EC_KEY *eckey);
+ int (*keygenpub)(EC_KEY *eckey);
+ int (*keycopy)(EC_KEY *dst, const EC_KEY *src);
+ void (*keyfinish)(EC_KEY *eckey);
+ /* custom ECDH operation */
+ int (*ecdh_compute_key)(unsigned char **pout, size_t *poutlen,
+ const EC_POINT *pub_key, const EC_KEY *ecdh);
+ /* Inverse modulo order */
+ int (*field_inverse_mod_ord)(const EC_GROUP *, BIGNUM *r,
+ const BIGNUM *x, BN_CTX *);
+ int (*blind_coordinates)(const EC_GROUP *group, EC_POINT *p, BN_CTX *ctx);
+ int (*ladder_pre)(const EC_GROUP *group,
+ EC_POINT *r, EC_POINT *s,
+ EC_POINT *p, BN_CTX *ctx);
+ int (*ladder_step)(const EC_GROUP *group,
+ EC_POINT *r, EC_POINT *s,
+ EC_POINT *p, BN_CTX *ctx);
+ int (*ladder_post)(const EC_GROUP *group,
+ EC_POINT *r, EC_POINT *s,
+ EC_POINT *p, BN_CTX *ctx);
+};