[Muscle] Protecting a PIN with keyed hashing?

[Joao Pedro]

Thanks Sébastien and everyone else who is participating!

Sébastien Lorquet <squalyl at gmail.com> wrote:

> the muscle applet is for global platform javacards right?
>
> Then about the GP secure channel already implemented
> (org.globalplatform.SecureChannel
> org.globalplatform.GPSystem.getSecureChannel() ) in these cards for
> secure messaging? it provides a mac+tdes encryption. also, writing
a
> software implementation is not difficult, if needed (to use other
> keys than SD's ones)
>

I think secure messaging could work well (I'm still trying to  
understand all the mechanisms involved in it).

But, if I'm not mistaken, secure messaging involves the existence of  
pre-shared keys. They can be symmetric (3DES), or assymetric (RSA) +  
Diffie-Hellman parameters to establish the session keys. So, this  
could be a bit of a hassle for users? I.e. the middleware would have  
to know/generate these keys, etc.

> sebastien
>
> ps: the muscle applet also support strong authentication with a
> challenge/response exchange. A 128 bits TDES key can be seen as a
> 16-character PIN, that can be right padded with zeroes or other if
> needed. what do you think of this?

It's an idea, but what are the security implications of just zero  
padding a PIN? It's an honest question :)