150 likes | 241 Views
Cryptanalysis and Improvement of a Secure Authentication Scheme with Anonymity for Wireless Communications. Date : 2012.09.13 Reporter : Hong Ji Wei Authors : Chin-Chen Chang, Wei-Bin Lee, and Chia -Yin Lee
E N D
Cryptanalysis and Improvement of a Secure Authentication Scheme with Anonymity for Wireless Communications Date:2012.09.13 Reporter : Hong Ji Wei Authors : Chin-Chen Chang, Wei-Bin Lee, and Chia-Yin Lee From : 2009 Fifth International Conference on Intelligent Information Hiding and Multimedia Signal Processing
INTRODUCTION 1 REVIEW OF WU,LEE AND TSAUR’S SCHEME 2 WEAKNESS OF WU,LEE AND TSAUR’S SCHEME 5 3 3 3 IMPROVED SCHEME CONCLUSION 6 4 4 4 OUTLINE SECURITY ANALYSIS
INTRODUCTION • A good user authentication scheme not only provides high security but also protects user privacy. • Lee, Hwang, and Liao pointed out some security weaknesses in Zhu-Ma’s scheme and presented an improved edition in 2006. • Wu, Lee, and Tsaur pointed out that Lee,HwangLiao’s scheme doesn’t achieve all security properties.
REVIEW OF WU,LEE AND TSAUR’S SCHEME This scheme can be divided into three phases • Initial Phase HA delivers a password and a smart card for MU through a secure channel. • First Phase FA authenticates to MU and establishes a session key. • Second Phase MU visits FA , and FA serves for MU.
REVIEW OF WU,LEE AND TSAUR’S SCHEME • Symbles MU : Mobile User HA : Home Agent of a mobile user FA : Foreign Agent of the network IDA: Identity of A TA : Timestamp of A CertA : Certificate of A (X)K : Symmetric Encryption EK(X) : Asymmetric Encryption h(X) : Hash X using hash function PWA : Password of A PA: Public key of A SA: Private key of A
REVIEW OF WU,LEE AND TSAUR’S SCHEME • Initial phase HA MU IDMU PWMU=h(N||IDMU) Registration PWMU , r , IDHA, h(.) Secure Channel
REVIEW OF WU,LEE AND TSAUR’S SCHEME • First phase FA HA MU
REVIEW OF WU,LEE AND TSAUR’S SCHEME • Second phase • In order to enhance the efficiency, while MU stays with the same FA, the new session key ki can be derived from the unexpired previous secret knowledge xi−1 and a fixed secret x as FA MU Authentication
WEAKNESS OF WU,LEE AND TSAUR’S SCHEME • Anonymity FA HA MU
WEAKNESS OF WU,LEE AND TSAUR’S SCHEME • Impersonate attack • If MU’s smart card is stolen by attacker who can perform impersonate attack.
IMPROVED SCHEME • First phase FA HA MU
IMPROVED SCHEME • Initial phase HA MU IDMU PWMU=h(N||IDMU) Registration PWMU , r , IDHA, h(.),h(N) Secure Channel
IMPROVED SCHEME • Our improved scheme can against the impersonation attack. • Assume that an attacker can intercept n,IDHA,TMU • (h(IDMU)||x0||x)L transmitted from MU and modify • this message as n,IDHA,TMU,(h(IDMU’)||x0’||x’)L • However, the attacker still can’t forge a correct n to • pass the authentication processes without knowing • HA’s secret keyNand realIDMU
CONCLUSION • We demonstrate some security flaws in Wu,Lee Tsaur’s scheme and propose an improvement to overcome these drawbacks. • The security analysis shows that our proposed scheme can solve these weaknesses by modifying some procedures of original scheme.