On the Key Schedule Strength of PRESENT
Source: University of Portsmouth
The PRESENT block cipher is an ultra-lightweight substitution-permutation network aimed at extremely constrained environments such as RFID tags and sensor networks. Hardware efficiency was one of its most important design goals, and at 1570 GE it really is one of the very few realistic options in such constrained environments for providing an adequate security level. PRESENT works with two key lengths, 80 and 128 bits, and operates over 64-bit blocks with a very simple round scheme which is iterated 31 times.