The term counterchallenge is identified in base64 scheme by the sequence Y291bnRlcmNoYWxsZW5nZQ==, while the MD5 signature is equal to 0b1017af66d62f0b029f2beac0e28cd6. The ASCII encoding of counterchallenge in hexadecimal notation is 636f756e7465726368616c6c656e6765.