Re: [tor-dev] adding smartcard support to Tor

On Sat, Oct 17, 2015 at 9:36 PM, Ken Keys <kenkeys@xxxxxxxxxxx> wrote:

What is the advantage of a smart card over a standard encrypted thumb drive?

On 10/17/2015 11:19 AM, Razvan Dragomirescu wrote:
> Thank you Ivan, I've taken a look but as far as I understand your
> project only signs the HiddenService descriptors from an OpenPGP card.
> It still requires each backend instance to have its own copy of the
> key (where it can be read by an attacker). My goal is to have the HS
> private key exclusively inside the smartcard and only sign/decrypt
> with it when needed but never reveal it. An attacker should not be
> able to steal the key and host his own HS at the same address - the
> address would be effectively tied to the smartcard - whoever owns the
> smartcard can sign HS descriptors and decrypt traffic with it, so he
> or she is the owner of the service.
>
> Best regards,
> Razvan
>
> --
> Razvan Dragomirescu
> Chief Technology Officer
> Cayenne Graphics SRL
>
> On Sat, Oct 17, 2015 at 4:43 AM, Ivan Markin <twim@xxxxxxxxxx

> <mailto:twim@xxxxxxxxxx>> wrote:
>
>Â Â ÂHello,
>Â Â ÂRazvan Dragomirescu:
>Â Â Â> I am not sure if this has been discussed before or how hard it would be to
>Â Â Â> implement, but I'm looking for a way to integrate a smartcard
>Â Â Âwith Tor -
>Â Â Â> essentially, I want to be able to host hidden service keys on
>Â Â Âthe card. I'm
>Â Â Â> trying to bind the hidden service to a hardware component (the
>Â Â Âsmartcard)
>Â Â Â> so that it can be securely hosted in a hostile environment as
>Â Â Âwell as
>Â Â Â> impossible to clone/move without physical access to the smartcard.
>
>Â Â ÂI'm not sure that this solution is 100% for your purposes. But
>Â Â Ârecently
>Â Â ÂI've added OpenPGP smartcard support to do exactly this into
>Â Â ÂOnionBlance
>Â Â Â[1]+[2]. What it does is that it just signs a HS descriptor using
>Â Â ÂOpenPGP SC (via 'Signature' or 'Authentication' key). [It's still a
>Â Â Âpretty dirty hack, there is no even any exception handling.] You
>Â Â Âcan use
>Â Â Âit by installing "manager/front" service with your smartcard in it via
>Â Â ÂOnionBalace and balancing to your actual HS. There is no any bandwidth
>Â Â Âlimiting (see OnionBalance design). You can setup OB and an actual
>Â Â ÂHS on
>Â Â Âthe same machine for sure.
>
>Â Â Â> I have Tor running on the USBArmory by InversePath (
>Â Â Â> http://inversepath.com/usbarmory.html ) and have a microSD form
>Â Â Âfactor card
>Â Â Â> made by Swissbit (
>Â Â Â>
>Â Â Âwww.swissbit.com/products/security-products/overwiev/security-products-overview/

>Â Â Â<http://www.swissbit.com/products/security-products/overwiev/security-products-overview/>

>Â Â Â> ) up and running on it. I am a JavaCard developer myselfÂ and I have
>Â Â Â> developed embedded Linux firmwares before but I have never
>Â Â Âtouched the Tor
>Â Â Â> source.
>
>Â Â ÂThere is a nice JavaC applet by Joeri [3]. It's the same applet that
>Â Â ÂYubikey is using. You can find well-written tutorial of producing your
>Â Â ÂOpenPGP card at Subgraph [4].
>
>Â Â Â>
>Â Â Â> Is there anyone that is willing to take on a side project doing
>Â Â Âthis? Would
>Â Â Â> it be just a matter of configuring OpenSSL to use the card (I
>Â Â Âhaven't tried
>Â Â Â> that yet)?
>
>Â Â ÂI'm not sure that it is worth to implement a card support in
>Â Â Âlittle-t-tor itself. As I said, all the logic is about HS descriptor
>Â Â Âsigning. Python and other langs that provide readablity will provide
>Â Â Âsecurity then.
>Â Â ÂI think/hope so.
>
>Â Â Â[1] https://github.com/mark-in/onionbalance
>Â Â Â[2] https://github.com/mark-in/openpgpycard
>Â Â Â[3] http://sourceforge.net/projects/javacardopenpgp/
>Â Â Â[4] https://subgraph.com/sgos/documentation/smartcards/index.en.html
>
>Â Â ÂHope it helps.
>Â Â Â--
>Â Â ÂIvan Markin
>Â Â Â/"\
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