Literally, CD means compact disc, and KEY means key, which translates to "key to open compact disc". The technical term is registration code, which is actually the registration code and key of software.
But the difference between this password and ordinary password is that it can only be entered by reading the CD, not from the keyboard, even if others know it. General online banking needs it to ensure the security of customer information.
Extended data
1. There are two kinds of keys: symmetric key and asymmetric key.
Symmetric key encryption, also known as private key encryption or session key encryption algorithm, has the greatest advantage of fast encryption and decryption, which is suitable for encrypting a large number of data, but key management is difficult.
2. Asymmetric key encryption system, also known as public key encryption. It needs to use different keys to complete encryption and decryption operations, one is publicly released, that is, the public key, and the other is privately kept by the user himself, that is, the private key. The sender of information uses public key encryption, while the receiver of information uses private key decryption. The public key mechanism is flexible, but the speed of encryption and decryption is much slower than that of symmetric key encryption.
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