Encryption is the process of encrypting some message, referred to as plaintext, into unrecognizable ciphertext. Without certain information (a key of some sort), it is extremely hard to reconstruct the plaintext from the ciphertext. Someone equipped with the proper key, however, can easily decrypt the ciphertext, revealing the original plaintext—at least, if the chosen encryption function is not one-way.
Passwords are stored in encrypted form. Password encryption, however, is usually one-way. There is no key to
decrypt an encrypted password. Such a key is not needed, and the encryption can be made stronger if it doesn’t need to be reversible. Encryption has many other uses in online business, both for storing data on the server and transmitting it across the network.