backend.py 文件源码

def elliptic_curve_supported(self, curve):
        if self._lib.Cryptography_HAS_EC != 1:
            return False

        try:
            curve_nid = self._elliptic_curve_to_nid(curve)
        except UnsupportedAlgorithm:
            curve_nid = self._lib.NID_undef

        ctx = self._lib.EC_GROUP_new_by_curve_name(curve_nid)

        if ctx == self._ffi.NULL:
            errors = self._consume_errors()
            self.openssl_assert(
                curve_nid == self._lib.NID_undef or
                errors[0][1:] == (
                    self._lib.ERR_LIB_EC,
                    self._lib.EC_F_EC_GROUP_NEW_BY_CURVE_NAME,
                    self._lib.EC_R_UNKNOWN_GROUP
                )
            )
            return False
        else:
            self.openssl_assert(curve_nid != self._lib.NID_undef)
            self._lib.EC_GROUP_free(ctx)
            return True