Hi, I'm writing a review of OpenPGP keycards (yubikey, FST-01, Nitrokey, etc) for LWN.net and one of the things I need to cover is the question of the "closing" of the Yubikey 4, switching from a partially closed to a fully-closed model. Their rationale is explained here:
https://www.yubico.com/2016/05/secure-hardware-vs-open-source/ In particular, I find this paragraph interesting: > Given these developments, we, as a product company, have taken a clear > stand against implementations based on off-the-shelf components and > further believe that something like a commercial-grade AVR or ARM > controller is unfit to be used in a security product. In most cases, > these controllers are easy to attack, from breaking in via a > debug/JTAG/TAP port to probing memory contents. Various forms of fault > injection and side-channel analysis are possible, sometimes allowing > for a complete key recovery in a shockingly short period of time. In > this specific context (fault injection and side-channel analysis), an > open source strategy would provide little or no remedy to a serious > and growing industry problem. One could say it actually works the > other way. In fact, the attacker’s job becomes much easier as the code > to attack is fully known and the attacker owns the hardware > freely. Without any built-in security countermeasures, the attacker > can fully profile the behavior in a way that is impossible with a > secure chip. In effect, this is a reasonable point: open hardware *may* just be more vulnerable to such attacks than a "secure chips" (whatever that means). Now, I personally feel this argument isn't so great: you just shift the trust into proprietary hardware, and you have no garantees that is doing anything you actually need it to do - I think I have plenty of resources to articulate that fundamental free vs closed design argument on my own. However, I wonder if there is a less theoritical argument to be made. For example, I notice that in the 3G design here: https://trac.cryptech.is/wiki/Hardware There is a "tamper detection" chip that I guess is designed to work around physical tampering? Is that something that could address the concerns of the Yubico people above? Or is this just protection against physical tampering? I guess another way to ask the question is: how exactly does that "secure hardware" work that it makes it so attractive to the Yubico people? Why can't that be implemented in an open design? Yubico seem to say there are no "major players" providing such a chip design - but couldn't such a system be designed with multiple commodity hardware components without putting all the trust in a single chip? Is that what the Cryptech designs are trying to do? Thanks for any comments or feedback, A. -- Antoine Beaupré LWN.net _______________________________________________ Tech mailing list Tech@cryptech.is https://lists.cryptech.is/listinfo/tech
