Linux 7.3 Adds New AES Library APIs That Set Up Future Crypto Speedups

Updated Oct. 26, 2026, 3:28 a.m. ET: Adds that Linux 7.3 shipped as a stable kernel on Oct. 18.

Linux 7.3 gives the kernel new library APIs for most of the AES encryption modes it relies on. Eric Biggers of Google landed the work during the merge window, and Phoronix reported that it covers ECB, CBC, CBC-CTS, CTR, XCTR, XTS, GCM and CCM.

Biggers explained the motivation in his pull request. “These AES modes have many in-kernel users that are currently using the crypto_skcipher or crypto_aead APIs. These existing APIs are difficult to use and inefficient. Until now, the lack of proper library support for these has been the main gap in the crypto library,” he wrote.

What Landed in 7.3

The pull implements the new APIs on top of the library’s existing single-block AES support. It moves the only user of the old AES-GCM library API to the new, more flexible interface and then removes the old API. It also wires the new APIs into the traditional crypto API as crypto_skcipher and crypto_aead algorithms, so they are covered by the crypto self-tests and already run in production on systems without architecture-optimized code for these modes.

The Payoff Comes Later

The headline speedups are not in this release. Biggers said the new APIs are “a prerequisite for migrating the architecture-optimized code for these AES modes (i.e. arch/*/crypto/aes*) into the library, which as usual will eliminate a lot of redundant ‘glue’ code.” Unlike earlier migrations such as SHA-512, the AES modes were too much to finish in one cycle and too intertwined to move one at a time.

“Most of the benefits (reductions in lines of code, performance improvements, etc.) will follow in later cycles when architecture-optimized code is migrated into the library and users of crypto_skcipher and crypto_aead are updated to use the new APIs,” he wrote.

For kernel developers, the change means simpler calls for disk encryption, networking and other subsystems that use AES. For everyone else, it sets up cleaner and faster encryption paths in coming releases, built on the same library approach that has already simplified the kernel’s hash code.