Given that they've already decided to include support in Chrome itself for accessing USB hardware security tokens for U2F, I see no reason why they couldn't do

Given that they've already decided to include support in Chrome itself for accessing USB hardware security tokens for U2F, I see no reason why they couldn't do the same with End to End + OpenPGPCards like the Yubikey NEO, which happens to also be a U2F device. It would provide a solution to some of the issues they document on their own Wiki regarding secret keys being stolen by an attacker through another Chrome extension, another application on the system, etc. EDIT: YES! I missed this part[1] in the Wiki earlier: "Additionally, we plan to add remote private key support in the future. When support for that is ready, high-risk users could protect their secret keys (stored, e.g., in a hardware USB device) from compromise even when an adversary introduces a backdoor in the source code." [1] https://github.com/google/end-to-end/wiki/Threat-model#backdoor-in-end-to-end-source-code https://github.com/google/end-to-end/wiki/Threat-model#backd...