AES (Advanced Encryption Standard)
Also known as: AES-256, AES encryption, Advanced Encryption Standard
AES (Advanced Encryption Standard) is the most widely used symmetric encryption algorithm, adopted as a U.S. government standard and built into nearly every device and app. AES-256 — the 256-bit key version — is the common choice for disk and file encryption.
- Symmetric cipher and a U.S. government standard
- AES-256 and AES-128 differ by key length in bits
- Hardware-accelerated on most modern devices
Why AES is everywhere
AES is a symmetric cipher: the same key encrypts and decrypts, which makes it fast enough to scramble entire drives in real time. It became the official U.S. government standard in the early 2000s and has since been adopted worldwide for everything from device storage to Wi-Fi and HTTPS.
Most modern processors include hardware AES acceleration, so encrypting a phone or laptop adds almost no slowdown. Apple, Google, Microsoft, and password managers all rely on it.
What AES-128 and AES-256 mean
The number is the key length in bits. AES-256 uses a 256-bit key and AES-128 a 128-bit key; a longer key means exponentially more possible combinations to guess. Both are considered secure today, with AES-256 favored for long-term and high-value data.
The weak link is rarely AES itself but the passphrase guarding the key. A strong, unique passphrase keeps AES doing its job; a guessable one undermines it no matter the key length.