The code is written for 8-bit microcontrollers as the comments mention.

You'll have to look for 8-bit and 16-bit assumptions if you want to port it

to a 32 bit machine.

Thanks for the reply!

I've found some pseudo code for AES ( http://www.cs.utsa.edu/~wagner/laws/AESintro.html ) that has helped me understand this some more -- but I'm still struggling to find where the '8 bit assumptions' are precisely.

It seems from what I can find one difference between the 8 and 32 bit micros with Arduino is the size of int variables (16 and 32 bit, respectively). Are variables such as the two below therefore the ones causing me problems in this library?

int n_block

int keylen

For instance the line:

byte next = keylen ;

byte is 8 bits regardless, but the size of keylen is different between the 8 and 32 bit systems. Is this my problem?

Any additional pointers would be greatly appreciated as I try to work through this.