AES-256 (ECB) implementation in Java.
Once you have Java SE runtime environment set up, then you may run the following command to start with.
git clone https://github.com/poanchen/AES.git
cd AES
javac AES.java
Your key file should contains a single line of 64 hex characters, which represents a 256-bit key.
Your inputFile or plaintext should have 32 hex characters per line.
For example, your input file might look something like this,
0A935D11496532BC1004865ABDCA4295
00112233445566778899AABBCCDDEEFF
...
Run encryption command
java AES e key plaintext
Run decryption command
java AES d key plaintext.enc