secret key:    
enter secret message:

secret message encrypted:
  
Encryption is the process of encoding plaintext into an unreadable ciphertext. The encryption key (secret key) specifies how a message is to be encoded. The authorized should be able to decode the ciphertext using the decryption algorithm that requires the secret key. The unauthorized must not have access to the key. By viewing the ciphertext, the unauthorized should not be able to determine anything about the original plaintext.