The Wertheim SafeController Family 65000, Controller 65000 - AssemblyVersion 6.11.8130.22319, uses weak custom cryptographic algorithms with hard-coded cryptographic keys to protect communication. An attacker in an adversary-in-the-middle position can decrypt the data traffic. During reassessment, it was possible to break the encryption/decryption routine and decrypt messages without knowledge of the encryption key. It was also possible to gain knowledge about the encryption key by intercepting enough messages.