Date Added: Oct 2011
The key exchange protocols using passwords achieved great attention due to their simplicity and efficiency. On the other hand these protocols should resist all types of password guessing attacks, as the password is of low entropy. Recently, Lu and Cao proposed a Three PArty Simple Key Exchange protocol (S-3PAKE). It is an extension of Abdella and Pointchval SPAKE protocol. Later Guo et al. proposed a man in the middle attack and undetectable online password guessing attack on the above protocol.