Ciphertext

In cryptography, ciphertext or cyphertext is the result of encryption performed on plaintext using an algorithm, called a cipher. Ciphertext is also known as encrypted or encoded information because it contains a form of the original plaintext that is unreadable by a human or computer without the proper cipher to decrypt it. Decryption, the inverse of encryption, is the process of turning ciphertext into readable plaintext. Ciphertext is not to be confused with codetext because the latter is a result of a code, not a cipher.

Let ${\displaystyle m\!}$ be the plaintext message that Alice wants to secretly transmit to Bob and let ${\displaystyle E_{k}\!}$ be the encryption cipher, where ${\displaystyle _{k}\!}$ is a cryptographic key. Alice must first transform the plaintext into ciphertext, ${\displaystyle c\!}$, in order to securely send the message to Bob, as follows:

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