Without knowledge of the secret, however, this process is very difficult. The advantage of symmetric ciphers is that they tend to be much faster than asymmetric ciphers. They also function in a simpler manner, like a lock and key. The encryption mechanism is the lock used to protect information. Without the key, however, it is hard either to close or open the lock.
Asymmetric ciphers use a different strategy.
One secret is used for encryption, and another one is used for decryption. One can also reverse the process a message encrypted with the decryption key can be read using the encryption key. This may seem cumbersome, but it allows one to implement a public key cryptosystem. The way this works is that each person generates a pair of secrets, or keys. Then if Alice wants to send a message to Bob without letting Charlie read it, she encrypts the message with her private key and then encrypts it again with Bob s public key.