AES: The Encryption Standard That Protects Almost Everything
AES is the symmetric block cipher standardized by NIST in 2001, operating on 128-bit blocks with 128/192/256-bit keys — used in disk encryption, TLS, and CSPRNGs.
The Advanced Encryption Standard (AES) is a symmetric block cipher standardized by NIST in 2001 after a public competition that selected the Rijndael algorithm (developed by Belgian cryptographers Joan Daemen and Vincent Rijmen). ## Specifications - **Block size**: 128 bits (always) - **Key sizes**: 128, 192, or 256 bits (AES-128, AES-192, AES-256) - **Rounds**: 10, 12, or 14 depending on key size - **Operations**: SubBytes (S-box substitution), ShiftRows, MixColumns, AddRoundKey ## Where It's Used AES is essentially ubiquitous in modern computing: - **Disk encryption**: BitLocker, FileVault, LUKS - **Network security**: TLS/HTTPS (AES-GCM is the dominant cipher suite) - **CSPRNGs: Why Cryptographically Secure Random Numbers Are Essential for Security**: AES in counter mode as a deterministic random bit generator - **File encryption**: 7-Zip, GPG, VeraCrypt ## Hardware Acceleration Modern CPUs include **AES-NI** instructions (Intel since 2010, AMD since 2011) that perform AES rounds in hardware, achieving near-zero overhead — typically 1–3 CPU cycles per byte encrypted. This eliminated the historical performance excuse for not encrypting data at rest. ## Security Status No practical attack on full AES exists. The best theoretical attacks (biclique) reduce AES-256's effective security from 256 bits to ~254.4 bits — computationally irrelevant. AES is considered secure against both classical and (with 256-bit keys) quantum computers.