This first matrix is called the encoding matrix and its inverse is called the decoding matrix. The receiver of the message decodes it using the inverse of the matrix. Ciphertext: The message or information that is created after the cipher has been used.Īlthough there are different methods to encrypt and decrypt messages, we'll focus on a linear algebra based cipher, the Hill cipher, which uses a matrix as a cipher to encode a message, and it's extremely difficult to break when a large matrix is used. Plaintext: The message or information that is being encrypted. It's also used to recreate the original message, depending on the encryption mechanism used. Cipher: The procedure that will render a message unintelligible to the recipient. There are some essential concepts concerning Cryptography. Decryption is the reverse of encryption it is the transformation of encrypted data back into some intelligible form. Encryption is the transformation of data into some unreadable form, so, even those who can see the encrypted data cannot understand the hidden information. This is basically, the objective of Cryptography, the study of the techniques to protect sensitive communications by means of data encryption and its posterior decryption. Since humans invented the written language, they have tried to share information secretly.