1. A method of determining a modular remainder with respect to a polynomial of a message comprised of a series of segments, comprising: repeatedly: accessing a strict subset of the segments, the strict subset consisting of the most significant segments representing the message; transforming the strict subset of segments to into a smaller set of segments that are equivalent to the strict subset of the segments with respect to the modular remainder; and determining the modular remainder based on a set of segments output by the repeatedly accessing and transforming; and storing the determined modular remainder.