Hi, After a few weeks of hard work I have managed to add the CTR, CMAC and SIV modes of operation. The implemententation passes all the KATS I could find and is made as efficiently as possible without forgetting the risk of timing attacks over them. The patch is attached here and you can free it along with your library with a BSD-3 license as long as you recognize the authorship. Francisco Blas Izquierdo Riera (klondike) PS: Attached is also a set of commands I used with ghci to check quickly the implementation and which contain parts of the KATS I used, feel free to use them.