192-bit encryption definition
192-bit encryption is the middle key-size option of the Advanced Encryption Standard. Like every AES variant, it scrambles data in 128-bit blocks, but it does so with a 192-bit secret key and 12 transformation rounds (two more than AES-128, two fewer than AES-256). Because a 192-bit key offers 2¹⁹² possible combinations, it is astronomically harder to brute-force than AES-128.
See also: AES encryption, 128-bit encryption, 256-bit encryption
How strong is 192-bit AES?
- Brute-force resistance: Even with theoretical exascale computers, checking 2¹⁹² keys would take longer than the age of the universe.
- Cryptanalysis record: No practical attack has ever recovered a 192-bit AES key; published research targets reduced-round or toy versions only.
- Compliance status: AES-192 is approved by NIST and referenced in FIPS 197, making it acceptable for U.S. federal use where “greater than 128-bit” strength is required; however, AES-256 is often preferred for high-security contexts due to wider hardware support and perceived margin of safety.
Where is 192-bit encryption used?
- Hardware Security Modules (HSMs) that must support every AES size for policy flexibility.
- Certain IPsec and TLS cipher suites (e.g., AES-192-GCM) when administrators want more headroom than AES-128 without the full performance hit of AES-256.
- Regulated environments that mandate keys above 128 bits but do not strictly require 256-bit keys. In everyday consumer products, AES-192 is rarer because many chipsets either default to 128-bit (for speed) or jump straight to 256-bit (for marketing consistency).
