ciphertekst

Ciphertekst is the result of applying a cryptographic cipher to plaintext. It is an unreadable, scrambled form of the original message produced by an encryption algorithm using a key. The purpose of ciphertekst is to protect confidentiality, so that only authorized parties with the correct key can recover the original plaintext through decryption.

Ciphertekst is produced by either symmetric or asymmetric encryption. In symmetric schemes, the same key is used to encrypt and decrypt; in asymmetric schemes, a public key encrypts and a private key decrypts. Modern cryptography commonly uses algorithms such as AES, ChaCha20, or RSA, often with parameters like initialization vectors or nonces to ensure that identical plaintexts yield different ciphertexts. The ciphertext is typically binary data and may be transmitted or stored in encoded form, for example base64.

Security properties: ciphertext aims to provide confidentiality, but not by itself guarantee integrity or authenticity. An attacker might modify ciphertext to cause decryption to fail or to leak information. To protect integrity and origin, encryption is combined with authentication methods such as MACs or digital signatures. Effective secrecy also depends on keeping keys confidential and on using appropriate modes and padding to prevent leakage and certain types of cryptographic attacks.

Usage and context: ciphertext is central to secure communications, protected data storage, and many privacy-preserving applications. It is distinct from plaintext, and from hashed data or digital signatures. The study of ciphertext and its transformations under different keys is a core area of cryptanalysis, cryptographic design, and information security practice.