On cryptographic assumptions and challenges

Abstract

We deal with computational assumptions needed in order to design secure cryptographic schemes. We suggest a classification of such assumptions based on the complexity of falsifying them (in case they happen not to be true) by creating a challenge (competition) to their validity. As an outcome of this classification we propose several open problems regarding cryptographic tasks that currently do not have a good challenge of that sort. The most outstanding one is the design of an efficient block ciphers. © International Association for Cryptologic Research 2003.