Advanced Encryption Standard (AES)
The Advanced Encryption Standard (AES) is a symmetric block cipher adopted by the U.S. government and used worldwide to encrypt sensitive data using key sizes of 128, 192, or 256 bits.
AES was established as a federal standard by the National Institute of Standards and Technology (NIST) in 2001, replacing the older Data Encryption Standard (DES). It was originally published as the Rijndael cipher, named after its creators Joan Daemen and Vincent Rijmen, who won the NIST competition to select the new standard.
AES operates on fixed-size blocks of 128 bits and supports key lengths of 128, 192, or 256 bits. The algorithm processes data through multiple rounds of substitution, permutation, mixing, and key addition. AES-128 uses 10 rounds, AES-192 uses 12 rounds, and AES-256 uses 14 rounds. The increased number of rounds for longer keys provides additional security margins.
In practice, AES is used in various modes of operation such as GCM (Galois/Counter Mode), which provides both confidentiality and authenticated encryption, and CBC (Cipher Block Chaining). AES-256-GCM is widely recommended for new implementations because it combines strong encryption with integrity verification. AES is found in virtually every area of modern computing, including TLS connections, disk encryption, VPNs, and secure messaging applications.