nunodonato@gmail.com writes:
> sorry to disagree but i prefer the master password. remembering ONE
> password is not hard, even if it has to be a bit more complicated than
> the usual.
>
> biometric scans are very secure, thats for sure, but its no so
> pratical.. and you need another device for that. what happens when you
> go to a place where it is not available?
the issues are what are the treats and the countermeasures.
biometric information can be left around all over the place ... and
once compromised it can be a lot more difficult to re-issue a thumb
than it is to replace a compromised password (although there
have been a couple recent news items attempting to address
compromised biometrics).
frequently access passwords tend to be shared-secrets .... they tend
to be exposed in a lot more different places ... it is one of the
reasons for security recommendations that there has to be a unique
shared-secret for every unique security environment. This in turn
leads to people having several scores of different (shared-secret)
passwords that result in the difficult (human) memory problem 2and in
turn results the (shared-secret) password management problems.
http://www.garlic.com/~lynn/subpubkey.html#secret
The master password scenario tends to be simply a secret ... as
opposed to a shared-secret ... which tends to imply that there are a
much fewer places where they are exposed and may be subject to
compromise.
The basic model tends to be that there is some sort of container for
the authentication material ... either a software/file container
.... or a separate hardware token container.
The (master) password tends to be a countermeasure for a lost/stolen
"container" (whether it is a real physical container or purely
software container).
At a 100k foot level ... it is two-factor authentication:
* container (hardware or software), "something you have"
* (secret only, not shared-secret) password, "something you know"
.... lots of 3-factor related authentication posts
http://www.garlic.com/~lynn/subpubkey.html#3factor
multi-factor authenticatin carries with it the implication that the
different authentication factors are subject to different kinds of
vulnerability and threats (for instance "something you are" biometric
value and a "something you know" password value transmitted in the
same communication may be subject to a common evesdropping
vulnerability and replay attack ... negating the benefit of
having multi-factor authentication).
the overall integrity can be related to how easy it is to steal the
container, whether the owner realizes the container has been stolen
(physical or software copy), and how hard it is to crack the (master)
pin/password.
a separate hardware container may be harder to steal than a software
file resident on an extremely vulnerable internet connected
PC. Vulnerable, internet connected PC may also be subject to
keyloggers (capturing the master password) and sniffing (capturing the
actual shared-secret passwords as they are being used).
So compare various threat models to hardware token with private key
and infrastructures that replace shared-secret password registration
with registration of public keys ... and digital signature
verification in lieu of password checking.
Requiring unique shared-secret registration for every unique security
domain is because the shared-secret is used for both authentication as
well as origination (i.e. knowing the shared-secret can be sufficient
for impersonation). A public key can only be used for authentication,
but not for impersonation ... so the same public key can be registered
in a large number of different places w/o increasing the threat of
impersonation (that can happen if the same shared secret is repeatedly
used).
Correctly implemented digital signature protocols result in a unique
value for every authentication, eliminating threat of evesdropping and
replay attacks for impersonation.
A real hardware token tends to eliminate electronic, software theft
(which can happen with emulated software containers).
So a hardware token tends to require physical stealing the object.
For this situation, pin/password (required for token operation) is a
countermeasure for physical lost/stolen token ... as long as the
pin/password hasn't been written on the token.
A hardware token with a built in fingerprint sensor ... might leave
around a latent print on the sensor ... so if the token is stolen
... the thief may be able to lift the latent print and spoof the
sensor. Some organizations are featuring "line sensor" (where you have
to drag you finger across the sensor) as a security enhancement
(compared to full finger sensors where a latent print may be left
around).
--
Anne & Lynn Wheeler |
http://www.garlic.com/~lynn/