Cryptography
Encryption
Also known as: Enciphering
Definition
The cryptographic transformation of plaintext into ciphertext using an algorithm and key so that only authorized parties can recover the original data.
Examples
- HTTPS encrypts browser-to-server traffic using TLS.
- Full-disk encryption such as BitLocker or FileVault protects data on a stolen laptop.
Related terms
Decryption
The reverse cryptographic operation that converts ciphertext back into its original plaintext using the appropriate algorithm and key.
Symmetric Encryption
An encryption scheme in which the same secret key is used for both encryption and decryption, offering high speed and strong confidentiality when the key is shared securely.
Asymmetric Encryption
A cryptographic scheme that uses mathematically linked key pairs — a public key for encryption and a private key for decryption — to enable secure communication without prior secret sharing.
AES (Advanced Encryption Standard)
A NIST-standardized 128-bit block cipher with 128-, 192- or 256-bit keys, designed by Daemen and Rijmen and used as the dominant symmetric cipher worldwide.
Block Cipher
A symmetric cipher that encrypts fixed-size blocks of plaintext with a secret key, usually combined with a mode of operation to handle data of arbitrary length.
Stream Cipher
A symmetric cipher that encrypts data one bit or byte at a time by XORing it with a pseudorandom keystream derived from a key and nonce.