Secure SAS-like password authentication schemes

Recently, there are several articles proposed for the so-called SAS password authentication scheme with lower storage, processing, and transmission overheads. For benefiting from these advantages, there are a series of researches on the SAS-like schemes. However, as knowledge of cryptanalysis has involved, a series of modification have been made. Unfortunately, those enhancements have still security flaws. In this paper, a security issue is found in the latest modification and removed to form a new one. The proposed schemes not only keep the original advantages but also highlight a feature, mutual authentication between a user and a remote server, found in many authentication protocols but not found in the SAS-like schemes. D 2004 Elsevier B.V. All rights reserved.