Definition
AES, or Advanced Encryption Standard, is a symmetric block cipher widely adopted as a global standard for encrypting sensitive data. It operates on fixed size blocks of data, typically 128 bits, using a key of 128, 192, or 256 bits to perform a series of substitution and permutation operations. In practice, AES is used to secure information at rest and in transit, ensuring confidentiality and integrity against unauthorized access. This is crucial for protecting everything from personal financial details to classified government communications. For example, secure websites use AES to encrypt the data exchanged between your browser and the server during online transactions. Unlike asymmetric encryption which uses separate keys for encryption and decryption, AES uses the same secret key for both processes. You will encounter AES concepts in cybersecurity certifications like CompTIA Security+, CySA+, and CISSP.