AESToy: a tiny C++ AES implementation

WARNING

This implementation is for educational-purposes only. It should never be used in production environment, as it is probably vulnerable to lots of side-channels and potentially other kind of attacks.

For this purpose, the library is licensed to GPLv3, so that it won't end up "accidentally" in a proprietary software.

Introduction

AESToy is a minimal C++ implementation of the AES128 block cipher. It is meant for educational purpose only, and to provide a simple implementation that is easily readable. It also provides various tools to play with AES, like dumping/inverting the key schedule, block encryption/decryption, and so on...

Compilation

This needs no dependencies. You can compile it using CMake:

$ cd /path/to/src && mkdir build && cd build
$ cmake -DCMAKE_BUILD_TYPE=release .. && make
$ make test

Usage

There are some tools that could be useful:

aes_keyexpand

This dumps the key schedule on stdout:

$ ./tools/aes_keyexpand 000102030405060708090A0B0C0D0E0F
000102030405060708090A0B0C0D0E0F
D6AA74FDD2AF72FADAA678F1D6AB76FE
B692CF0B643DBDF1BE9BC5006830B3FE
B6FF744ED2C2C9BF6C590CBF0469BF41
47F7F7BC95353E03F96C32BCFD058DFD
3CAAA3E8A99F9DEB50F3AF57ADF622AA
5E390F7DF7A69296A7553DC10AA31F6B
14F9701AE35FE28C440ADF4D4EA9C026
47438735A41C65B9E016BAF4AEBF7AD2
549932D1F08557681093ED9CBE2C974E
13111D7FE3944A17F307A78B4D2B30C5

aes_invertkeyexpand

This reverts the key schedule, starting from a round key, and print the original key:

$ ./tools/aes_invertkeyexpand 5E390F7DF7A69296A7553DC10AA31F6B 6
000102030405060708090A0B0C0D0E0F

aes_process

This encrypt/decrypt a block using AES:

$ $ ./tools/aes_process 0 000102030405060708090A0B0C0D0E0F AABBCCDDEEFF0001AABBCCDDEEFF0001
9999F4D833C97BBD72C93449EDDEE73F
$ ./tools/aes_process 1 000102030405060708090A0B0C0D0E0F 9999F4D833C97BBD72C93449EDDEE73F
AABBCCDDEEFF0001AABBCCDDEEFF0001

Final note

Again, do not use this in production!