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When we start shipping revokable 64gb compressed one time pad data sticks, I'll have some faith in crypto. Until then, one eye always open.
by gouranga 14y ago
When we start shipping revokable 64gb compressed one time pad data sticks, I'll have some faith in crypto.
Until then, one eye always open.
- romaniv 14y agoI think the motivation behind RSA tokens is that while you can steal them, you shouldn't be able to silently copy one. That's not something you get with an OTP on a USB stick, unless you invest into tamper-proof hardware. Aside from that, I'm not sure why OTPs aren't more commonly used. They're easy to reason about, and while you still need some protocol to use them correctly, it would seem that protocol would be much simpler than for fancy crypto like RSA.
- tptacek 14y agoThe "some protocol to use them" part is where the crypto in the hardware devices in this attack fell down, which is one of the many reasons people don't use OTPs: they shift all of the security of the system from the cryptographic algorithm itself to the protocol, which is the most error-prone part of the system. Neither RSA nor AES were damaged by this attack.
- tedunangst 14y agoYou would need a OTP for every one you wanted to talk to. If I had a OTP for every https site I visit, I'd need hundreds. Facebook would need hundreds of millions. They're not going to be mailing out USB sticks on a weekly basis.
- romaniv 14y agoYou need an RSA token for each server you talk to as well. It's not a replacement for asymmetric cryptography.
- tptacek 14y agoYou'd "need" (in the handwaviest sense, because nobody had designed a crypto token based on one-time pads here) OTP content for every authentication attempt.
- gizzlon 14y ago"They're not going to be mailing out USB sticks on a weekly basis" Mailing? That's not secure enough.. You have to go to Facebook HQ and get your weekly OTP. Daily if you post a lot of images =)
- ramchip 14y agoIf it can be compressed, you should probably not trust your pad ;)