AES-NI
Definition
AES New Instructions: hardware AES acceleration introduced on Intel Westmere (2010) and AMD Bulldozer (2011) and now ubiquitous. Single-cycle round operations make AES-128-GCM run at multiple GB/s per CPU core and produce constant-time, side-channel-resistant code.
- Full form
- AES New Instructions
- Intel introduction
- Westmere, 2010
- AMD introduction
- Bulldozer, 2011
- Throughput
- Multiple GB/s per core for AES-128-GCM
Common questions
Why does hardware AES matter for forensic tooling rather than just performance?+
A software AES implementation using lookup tables can leak timing information tied to the key through cache access patterns, whereas AES-NI performs the rounds in fixed-time silicon, closing that side-channel.
Does the absence of AES-NI make an older device's encryption easier to break?+
No, it only makes software AES slower to compute, not weaker; brute-forcing the key remains computationally infeasible regardless of whether the instructions are hardware-accelerated.
Related terms
- AEAD
- Authenticated Encryption with Associated Data. Combines confidentiality and integrity in one primitive. AES-GCM and ChaCha20-Poly1305 are the two modern standards. TLS 1.3...
- Block Cipher
- A symmetric cipher that operates on fixed-size blocks (typically 64 or 128 bits) under a key. AES is a 128-bit-block cipher; DES...
- Constant-Time Crypto
- An implementation whose execution time, memory access pattern and power profile do not depend on the secret key or plaintext. The defence...
- Mode of Operation
- The wrapping protocol that defines how a block cipher handles arbitrary-length data, what IV or nonce is used, and whether integrity is...
- Stream Cipher
- A symmetric cipher that produces a pseudo-random keystream which is XORed bit-by-bit or byte-by-byte with the plaintext. RC4 (legacy), ChaCha20 (current). Stream...