FreeBSD random number generator broken for last 4 months [LWN.net]

FreeBSD random number generator broken for last 4 months

Posted Feb 19, 2015 11:42 UTC (Thu) by Otus (subscriber, #67685)
In reply to: FreeBSD random number generator broken for last 4 months by cesarb
Parent article: FreeBSD random number generator broken for last 4 months

In ssh's case, say the server's RNG is broken. Which nonces will that affect and which keys can thus be leaked? The host keys only or also client keys?

And the same questions for if the client is the one with a buggy RNG.

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FreeBSD random number generator broken for last 4 months

Posted Feb 19, 2015 12:03 UTC (Thu) by cesarb (subscriber, #6266) [Link]

> In ssh's case, say the server's RNG is broken. Which nonces will that affect and which keys can thus be leaked? The host keys only or also client keys?

One can't leak what one doesn't have. If the system with the broken RNG doesn't have a private key, it can't leak it. So in the server's case, only the host key (which the server has the private key for) can be leaked. Of course, as I said before, I don't know if openssh has anything (like use of deterministic DSA) which would prevent the leak.

> And the same questions for if the client is the one with a buggy RNG.

The client only has access to the client keys, so it can only leak them.