The reality has been imho, since the mid-90s that the authentication issues
mentioned below (capture and misuse between entry device and processing
device) are generic attack models, and can best be addressed by placing
authentication and entry functions in the same
tamper-proof/tamper-evident/resistant device. This includes PIN/password
entry and biomeric capture.
By necessity, authenication therefore needs a smartcard/secured storage
device carried by the user so that authicaiton can occur at the user's
location.
This then leads to every possible recipient/relying party to trust the
output of all authentication devices though some mechanism, consequently
this will only be deployed within definable communities of interest, in my
view. This is fine, since I don't want or need too authenticate myself to
everyone, only those with whom I have a trust relationship.
Just mho
Lyal
-----Original Message-----
From: full-disclosure-bounces@lists.grok.org.uk
[mailto:full-disclosure-bounces@lists.grok.org.uk] On Behalf Of Michael
Holstein
Sent: Thursday, 24 November 2005 7:42 AM
To: full-disclosure@lists.grok.org.uk
Subject: Re: [Full-disclosure] SmartCards programming...
The tough part here is figuring out how to have the software open the
file, but ensure that the contents are in fact inaccessible without
the smart card. In particular, securely handling the data after
opening to ensure that the data can't be saved in an unencrypted form
is fiendishly difficult, as every single DRM scheme to date has
demonstrated....
And even if you do get the programming bits right, there's still ways to
get the hardware to cough it up -- a recent example being Bunnie's
adventures with the Xbox.
3) Key management - more actual implementations manage to get this
wrong than do the actual crypto wrong. You can do the crypto in a
totally secure manner, but it's still total security manure suitable
for fertilizing the flower garden if a keystroke logger can easily
sniff the passphrase....
Short of placing the entry keyboard on the same physical device as the
card (think smartcard meets pocket calculator), you'll always be able to
grab the passphrase in this manner. I'm not quite sure there will ever
be a solution to that one.
Even with biometrics, there's nothing stopping me from reading the data
as it's taken from the input device (ie: the USB fingerprint reader) and
re-presenting that same data artifically.
~Mike.
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