m2crypto.py 文件源码

def verify(self, signature, msg):
        """
        Verify whether a given signature is correct for a message.

        :param signature: the given signature
        :param msg: the given message
        """
        length = len(signature) / 2
        r = signature[:length]
        # remove all "\x00" prefixes
        while r and r[0] == "\x00":
            r = r[1:]
        # prepend "\x00" when the most significant bit is set
        if ord(r[0]) & 128:
            r = "\x00" + r

        s = signature[length:]
        # remove all "\x00" prefixes
        while s and s[0] == "\x00":
            s = s[1:]
        # prepend "\x00" when the most significant bit is set
        if ord(s[0]) & 128:
            s = "\x00" + s
        # turn back into int
        r = int(hexlify(r), 16)
        s = int(hexlify(s), 16)
        # verify
        try:
            self.ec.verifier(encode_dss_signature(r, s), ec.ECDSA(hashes.SHA1()))
            return True
        except InvalidSignature:
            return False