AArch64cryptolib

Purpose

AArch64cryptolib is a from scratch implementation of cryptographic primitives aiming for optimal performance on Arm A-class cores.

The core concept of the AES-GCM implementations is to optimally schedule a "merged" AES-GCM kernel to make effective use of the available pipeline resources in existing CPUs.

Current optimisation targets:

1. LITTLE (Cortex-A53, Cortex-A55).
2. big (Cortex-A57, Cortex-A72, Cortex-A75, Cortex-A76 and Neoverse N1).
3. bigger (Neoverse V1).
4. biggereor3 (Neoverse V1).

Functionality

The library currently supports:

• AES-GCM

  • Encrypt and decrypt
  • 128b, 192b, and 256b keys
  • Bespoke IPsec variants which make some domain specific assumptions, and merges UDP checksum into AES-GCM decryption

• AES-CBC

  • Encrypt and decrypt
  • 128b key
  • SHA-1 and SHA-256 hash
  • Chained cipher + auth

Structure

AArch64cryptolib consists of:

1. A header file (AArch64cryptolib.h) with the interface to the library
2. Top implementation files (AArch64cryptolib_aes_gcm.c, AArch64cryptolib_aes_cbc.c) which provide several C functions supporting the library
3. Several asm optimised functions (in AArch64cryptolib_* folders) which target big, bigger and LITTLE microarchitectures, and are included inline in AArch64cryptolib_*.c when the pertinent compilation flags are set

Usage

Source files

Users of AArch64cryptolib have to include AArch64cryptolib.h in their source file and use the API described in that file.

Building library

• Native compilation with GCC basically need make
• To cross compile, use CROSS flag and point it to your cross compiler. e.g. make CROSS=aarch64-linux-gnu-

Compiler flags

Select one of the code paths optimised for big or LITTLE CPU implementations:

1. OPT=little
2. OPT=big
3. OPT=bigger
4. OPT=biggereor3

Add extra compiler flags or override default flags:

• EXTRA_CFLAGS=

Requirements

The implementation requires the Armv8a Cryptography Extensions. The biggereor3 implementation option requires the Armv8.2a SHA3 extension.

Restrictions

The choice of AES-GCM implementation is done at compile time.

License

SPDX BSD-3-Clause

See the included file 'LICENSE.md' for the license text.

Original Authors

• Samuel Lee (AES-GCM)
• Zbigniew Bodek (AES-CBC)

Maintainer

Ola Liljedahl (ola.liljedahl@arm.com)