At present, the encryption method adopted by anti-theft technology in game discs is not a password form, but a double-key technology. This is completely different from the encryption method we usually use on files, and its encryption password and decompression password are different. In this encryption system, each set of passwords has a public key that everyone knows and a private key that only the manufacturer or the user keeps. What is really confidential is the algorithm that produces both. Data encrypted by public key can only be decompressed by private key, which is what we call encryption. Private key encryption does not really encrypt data, it only generates an identification of this disk, and it can be determined whether this disk is encrypted with the corresponding private key with the public key. This is authentication, that is, digital signature. In this case, the data is not really encrypted.