Autokey cipher – Definition & Meaning

Cryptography is the practice of secure communication in the presence of third parties. It involves the use of codes and ciphers to protect the confidentiality of messages. One such cipher is the autokey cipher, which is a type of polyalphabetic substitution cipher that uses a key as a part of the encryption process. In this article, we will explore the definition and meaning of the autokey cipher.

Definitions

The autokey cipher is a type of cipher that uses a key to encrypt plaintext. It is a polyalphabetic substitution cipher, which means that it uses multiple alphabets to encrypt the message. The key used in the autokey cipher is generated from the plaintext itself, making it a self-synchronizing cipher.

Origin

The autokey cipher has been used for centuries, with the earliest known use dating back to the 16th century. It was first described by the French cryptographer Blaise de Vigenère in 1586. The autokey cipher was later improved by the German mathematician Johann Kaspar Zeuss in the 18th century.

Meaning in different dictionaries

According to the Oxford English Dictionary, the autokey cipher is “a cryptographic system in which the plaintext is used to generate the key for subsequent letters in the message.” The Merriam-Webster Dictionary defines it as “a cipher in which each letter of the plaintext is combined with a letter from a key that changes after each letter.”

Associations

The autokey cipher is often associated with other types of ciphers, such as the Vigenère cipher and the Beaufort cipher. These ciphers also use a key to encrypt plaintext and are polyalphabetic substitution ciphers.

Synonyms

Some synonyms of the autokey cipher include the self-synchronizing cipher, the running key cipher, and the keyphrase cipher.

Antonyms

As the autokey cipher is a type of cipher, there are no direct antonyms. However, other types of ciphers, such as the Caesar cipher and the Atbash cipher, are often contrasted with the autokey cipher.

The same root words

The word “cipher” comes from the Arabic word “sifr,” which means “zero” or “empty.” The word “autokey” comes from the Greek words “auto,” meaning “self,” and “key,” meaning “a device for opening or closing something.”

Example Sentences

1. The autokey cipher is a secure way to encrypt messages.
2. The autokey cipher was first described by Blaise de Vigenère in the 16th century.
3. The autokey cipher is a type of polyalphabetic substitution cipher.
4. The running key cipher is another name for the autokey cipher.
5. The autokey cipher uses a key generated from the plaintext itself.