basic implementation of AES in x86_64
This is a toy implementation with security vulnerabilities; it is unsuitable for any use other than pedagogy. I'm using it to learn a bit about crypto and X86_64 assembly. It is not particularly efficient as it is my first x86_64 program and I did not attempt to optimize the algorithm for the little-endian processor or use the long word length to my advantage. It also does not use SIMD or the AES-NI instructions available in the x86_64 as the point of the implementation was to learn the details of the algorithm.
AES-128 is a cipher that operates on 16-byte blocks. This implementation takes as input a block of 16 bytes and a 16-byte key and produces 16 bytes of encrypted output. It then runs the inverse cipher and verifies that the decrypted result is identical to the original data.
ben@nederland:~/src/aes$ ./aes
I3243F6A8885A308D313198A2E0370734 Input block to encrypt
S328831E0435A3137F6309807A88DA234 State vector (transformed input)
K2B7E151628AED2A6ABF7158809CF4F3C Key
O3925841D02DC09FBDC118597196A0B32 Encrypted output
O3243F6A8885A308D313198A2E0370734 Decrypted output (should be same as input)
ben@nederland:~/src/aes$
FIPS 197 (AES specification): [https://csrc.nist.gov/csrc/media/publications/fips/197/final/documents/fips-197.pdf]
Rijndael S-box [https://en.wikipedia.org/wiki/Rijndael_S-box]
Rijndael MixColumns [https://en.wikipedia.org/wiki/Rijndael_MixColumns]
Notes on implementing AES in go: [http://blog.nindalf.com/implementing-aes/]
X86_64 tutorial: [http://0xax.blogspot.com/2014/08/say-hello-to-x64-assembly-part-1.html]
NASM assembler reference: [http://www.nasm.us/xdoc/2.13.01/html/nasmdoc0.html]
GNU emacs NASM mode: [https://github.com/skeeto/nasm-mode]
Rocksoft CRC guide (best tutorial on polynomial arithmetic): [http://ross.net/crc/download/crc_v3.txt]
In ~/.emacs:
(load "~/src/nasm-mode/nasm-mode.el")
(require 'nasm-mode)
(add-to-list 'auto-mode-alist '("\\.\\(asm\\|s\\)$" . nasm-mode))