The Password Change Phase is Still Insecure

TL;DR

This paper critically examines the security of the password change phase in a recent smart card-based remote authentication scheme, revealing that it remains vulnerable despite previous modifications.

Contribution

It provides an in-depth analysis showing that the password change phase in Yoon et al.'s scheme is still insecure, highlighting ongoing security challenges.

Findings

The password change phase is vulnerable to attacks.

Previous modifications did not fully address security flaws.

The scheme remains insecure despite improvements.

Abstract

In 2004, W. C. Ku and S. M. Chen proposed an efficient remote user authentication scheme using smart cards to solve the security problems of Chien et al.'s scheme. Recently, Hsu and Yoon et al. pointed out the security weaknesses of the Ku and Chen's scheme Furthermore, Yoon et al. also proposed a new efficient remote user authentication scheme using smart cards. Yoon et al. also modified the password change phase of Ku and Chen's scheme. This paper analyzes that password change phase of Yoon et al's modified scheme is still insecure.