Password-based challenge-response



Hello all,

I have this question, hope to get some guidance...

Fora simple password-based challenge-response protocol between a user A
and a server S, where Pa is A's password, n is a random nonce generated
by the server, and h is a known cryptographic hash function.

1. S -> A: E(Pa,n)
2. A -> S: E(Pa,h(n))

How to show that this protocol is vulnerable to an off-line password
guessing attack? and how would the attack take place ?. Under which
circumstances would the vulnerability not be a problem?

any references and views are appreciated-----
thanks again....!merry christmas !!!

.



Relevant Pages

  • SecurityFocus Microsoft Newsletter #142
    ... MICROSOFT VULNERABILITY SUMMARY ... Mollensoft Enceladus Server Suite Clear Text Password Storage... ... FakeBO Syslog Format String Vulnerability ... Methodus 3 Web Server File Disclosure Vulnerability ...
    (Focus-Microsoft)
  • SecurityFocus Microsoft Newsletter #139
    ... OFF any Windows 2000 Managed Dedicated Hosting Solution from Interland. ... Sun ONE Application Server Plaintext Password Vulnerability ... Batalla Naval Remote Buffer Overflow Vulnerability ...
    (Focus-Microsoft)
  • SecurityFocus Microsoft Newsletter #140
    ... Cafelog b2 Remote File Include Vulnerability ... Webfroot Shoutbox Remote Command Execution Vulnerability ... Pablo Software Solutions Baby POP3 Server Multiple Connection... ... Microsoft Windows XP Nested Directory Denial of Service... ...
    (Focus-Microsoft)
  • SecurityFocus Microsoft Newsletter # 150
    ... - automatically set positive security policies for real-time protection, ... MICROSOFT VULNERABILITY SUMMARY ... Meteor FTP Server USER Memory Corruption Vulnerability ... MDaemon SMTP Server Null Password Authentication Vulnerabili... ...
    (Focus-Microsoft)
  • SecurityFocus Microsoft Newsletter #152
    ... MICROSOFT VULNERABILITY SUMMARY ... Real Networks Helix Universal Server Remote Buffer Overflow ... ... NEW PRODUCTS FOR MICROSOFT PLATFORMS ...
    (Focus-Microsoft)