The Advanced Encryption Standard (AES) is a symmetric encryption algorithm established by the U.S. National Institute of Standards and Technology in 2001 (NIST). It has been since regarded as a default algorithm for protecting sensitive data and classified information. AES encrypts data in a fixed block size of 128 bits and supports key sizes of 128, 192, or 256 bits. After the encryption of each block, they are combined to create the final ciphertext. AES is widely used in various applications, including secure communications, data storage, and network security.