dsskey.py 文件源码

def verify_ssh_sig(self, data, msg):
        if len(msg.asbytes()) == 40:
            # spies.com bug: signature has no header
            sig = msg.asbytes()
        else:
            kind = msg.get_text()
            if kind != 'ssh-dss':
                return 0
            sig = msg.get_binary()

        # pull out (r, s) which are NOT encoded as mpints
        sigR = util.inflate_long(sig[:20], 1)
        sigS = util.inflate_long(sig[20:], 1)

        signature = encode_dss_signature(sigR, sigS)

        key = dsa.DSAPublicNumbers(
            y=self.y,
            parameter_numbers=dsa.DSAParameterNumbers(
                p=self.p,
                q=self.q,
                g=self.g
            )
        ).public_key(backend=default_backend())
        verifier = key.verifier(signature, hashes.SHA1())
        verifier.update(data)
        try:
            verifier.verify()
        except InvalidSignature:
            return False
        else:
            return True