encipherer

An encipherer is a person or device that performs encipherment, the process of converting plaintext into ciphertext using an encryption algorithm and a key. The encipherer applies a transformation defined by a cipher to disguise the original message, with the intent of ensuring confidentiality against unauthorized readers. The counterpart who recovers the original text is the decipherer.

Historically, encipherers were individuals who manually applied substitution or transposition rules to messages, often under the direction of a sender. In modern cryptography, the term is less common; software and hardware implement encipherment, and the entities involved are described as encryption algorithms, ciphers, or encrypters rather than as people performing encipherment. The key used to encipher is critical; without it, the ciphertext should not reveal the plaintext.

Encipherment can be symmetric, where the same key is used for encryption and decryption, or asymmetric, where a public key is used for encryption and a private key for decryption. The strength of the encipherer’s work depends on the algorithm's security, the length of the key, and secure key management. Modern schemes often provide confidentiality, integrity, and authenticity through authenticated encryption or digital signatures.

Because terminology evolves, the term encipherer is encountered mainly in historical texts or descriptive discussions; contemporary writing more commonly uses encrypter, encryption algorithm, cipher, or simply "encrypted by".

See also: encryption, cipher, ciphertext, plaintext, decipherer, cryptography, key management.