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I think I understand what you were getting at by "there is no such thing as running out of entropy". Would you say there is such thing as "not having adequate e
by cbsmith 3y ago
I think I understand what you were getting at by "there is no such thing as running out of entropy". Would you say there is such thing as "not having adequate entropy"?
- tptacek 3y agoNot really. A CSPRNG is either initialized properly or it isn't. Once it is, entropy has ceased to be a concern. The original LRNG design misapprehends the purpose of continuous "entropy collection", which is about post-compromise security (it's essentially a rekeying operation), and not about any kind of cryptographic exhaustion.
- cbsmith 3y agoBut /dev/urandom will provide you with random numbers even if initialization has not completed, whereas /dev/random will not.
- tptacek 3y agoIt's best to think of this as an OS/distro detail; if you can reasonably expect /dev/urandom to give you insecure bits, your distro has a vulnerability. That said: today you'd just use some variant of getrandom.
- cbsmith 3y ago> It's best to think of this as an OS/distro detail; if you can reasonably expect /dev/urandom to give you insecure bits, your distro has a vulnerability. Isn't that more a function of hardware than software? The hardware random number generators on modern CPUs pretty much eliminate the need to worry about entropy...