Method raw_get_ecdh_key

src/pyelliptic/ecc.py:191–244

(self, pubkey_x, pubkey_y)

        return sha512(self.raw_get_ecdh_key(pubkey_x, pubkey_y)).digest()

    def raw_get_ecdh_key(self, pubkey_x, pubkey_y):
        try:
            ecdh_keybuffer = OpenSSL.malloc(0, 32)

            other_key = OpenSSL.EC_KEY_new_by_curve_name(self.curve)
            if other_key == 0:
                raise Exception("[OpenSSL] EC_KEY_new_by_curve_name FAIL ...")

            other_pub_key_x = OpenSSL.BN_bin2bn(pubkey_x, len(pubkey_x), 0)
            other_pub_key_y = OpenSSL.BN_bin2bn(pubkey_y, len(pubkey_y), 0)

            other_group = OpenSSL.EC_KEY_get0_group(other_key)
            other_pub_key = OpenSSL.EC_POINT_new(other_group)

            if (OpenSSL.EC_POINT_set_affine_coordinates_GFp(other_group,
                                                            other_pub_key,
                                                            other_pub_key_x,
                                                            other_pub_key_y,
                                                            0)) == 0:
                raise Exception(
                    "[OpenSSL] EC_POINT_set_affine_coordinates_GFp FAIL ...")
            if (OpenSSL.EC_KEY_set_public_key(other_key, other_pub_key)) == 0:
                raise Exception("[OpenSSL] EC_KEY_set_public_key FAIL ...")
            if (OpenSSL.EC_KEY_check_key(other_key)) == 0:
                raise Exception("[OpenSSL] EC_KEY_check_key FAIL ...")

            own_key = OpenSSL.EC_KEY_new_by_curve_name(self.curve)
            if own_key == 0:
                raise Exception("[OpenSSL] EC_KEY_new_by_curve_name FAIL ...")
            own_priv_key = OpenSSL.BN_bin2bn(
                self.privkey, len(self.privkey), 0)

            if (OpenSSL.EC_KEY_set_private_key(own_key, own_priv_key)) == 0:
                raise Exception("[OpenSSL] EC_KEY_set_private_key FAIL ...")

            if OpenSSL._hexversion > 0x10100000 and not OpenSSL._libreSSL:
                OpenSSL.EC_KEY_set_method(own_key, OpenSSL.EC_KEY_OpenSSL())
            else:
                OpenSSL.ECDH_set_method(own_key, OpenSSL.ECDH_OpenSSL())
            ecdh_keylen = OpenSSL.ECDH_compute_key(
                ecdh_keybuffer, 32, other_pub_key, own_key, 0)

            if ecdh_keylen != 32:
                raise Exception("[OpenSSL] ECDH keylen FAIL ...")

            return ecdh_keybuffer.raw

        finally:
            OpenSSL.EC_KEY_free(other_key)
            OpenSSL.BN_free(other_pub_key_x)
            OpenSSL.BN_free(other_pub_key_y)
            OpenSSL.EC_POINT_free(other_pub_key)
            OpenSSL.EC_KEY_free(own_key)
            OpenSSL.BN_free(own_priv_key)

    def check_key(self, privkey, pubkey):
        """