RE: Token authentication with web applications

["Michael Silk" <michaels () phg com au>]

Hi,
        As far as I have found is that the secure systems will perform
        some computation on the card itself, the computation is such that
        it is secure (i.e. no private data leaves the card, and other
        such things)

        So, in your situation obviously the computer where the key is plugged
        into isn't considered secure; so computation can't be done there.

        Perhaps you could look into utilising the users' palm pilots? If they
        have them ...

        If not, well, the only solution is to use a system that can be
        copied (i.e. cd's, printouts, and so on) and accepting the risk.

        Potentially (and this is just a very rough suggestion) you could
        have a secure server and the users' computers can request a token
        from that. (i.e. try and emulate the computational card-based system
        utilising a server instead of the card).

-- Michael


-----Original Message-----
From: Ivan Krstic [mailto:krstic () fas harvard edu]
Sent: Friday, 2 July 2004 8:48 AM
To: webappsec () securityfocus com
Subject: Token authentication with web applications


All,

I'm looking for people's experiences with cheap, uncomplicated token 
devices or other physical means of authentication that play nicely with 
more traditional authentication methods in web applications.

The cheapest solutions that came to mind are printing credit-card sized 
s/key cards, or burning mini-CDs with a key and an auth agent for users. 
Obviously, both methods are flawed (s/key cards can be copied down if 
left exposed, and that's assuming they're not taped to the monitor, 
while a stolen CD can be copied and replaced without evidence of 
tampering[1]), but would still raise the security bar at essentially no 
cost. More extensive authentication solutions are usually rather expensive.

Thoughts?

Cheers,
Ivan.


[1] The s/key printed cards at least address this insofar as the user, 
presuming he can be bothered with remembering which of the 100 s/keys he 
used last, can notice that an intruder gained access to the system.


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