We present MARVIN, a new parallelizable message authentication code (MAC) based on the ALRED family. The new algorithm is designed with resource-constrained platforms inmind and explores the structure of an underlying block cipher toprovide security at a small cost in terms of memory needs. Also,we show how MARVIN can be used as an authentication-onlyfunction or else in an authenticated encryption with associateddata (AEAD) scheme. We define a new AEAD proposal called LETTERSOUP, which is based on the mode ofoperation. Finally, we LFSRC analyze the security and performance of theresulting schemes. Copyright © 2008 John Wiley & Sons, Ltd.