The term principal diagonal is identified in base64 scheme by the sequence cHJpbmNpcGFsIGRpYWdvbmFs, while the MD5 signature is equal to 140d718e1f57e0a6fc8a076ecdcf703c. The ASCII encoding of principal diagonal in hexadecimal notation is 7072696e636970616c20646961676f6e616c.