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> Rolling your own random number generator should be considered the same as rolling your own crypto: by all means have a play in order to help understand the co

by Osmium 13y ago

> Rolling your own random number generator should be considered the same as rolling your own crypto: by all means have a play in order to help understand the concepts, but unless you are an expert in the relevant mathematics+electronics don't every use your own in production. I'm not sure it's quite as bad as rolling your own crypto. If you have a RNG you can run it through statistical tests, e.g. NIST's DIEHARD tests. If you know the physical principles on which your device works, I can't imagine a scenario where you'd be getting randomly-distributed bits that aren't actually random. And if you add those bits to your system's entropy pool, rather than using them directly, then it should be fine. That said, I agree that you still shouldn't use it in a production environment! Your suggestion for e.g. the RPi RNG is problematic because (last I checked) there wasn't information online about how that actually works. For RNGs, I'd much prefer trusting my own design than a black box which could be outputting an AES-encoded string of all 0s for all I know!

mistercow 13y ago
>That said, I agree that you still shouldn't use it in a production environment! I wonder though. There's a possibility that you'll screw something up and miss it during testing, but I've also seen some scary analyses of expensive off the shelf RNG hardware. I'd say that if you're in a position of highly restricted capital that requires generation of tons and tons of secure random numbers, the ugly truth is that an open source DIY solution for generating your own entropy (especially if you can use multiple designs that are separately tested) might be safer than dumping your limited resources on proprietary unknowns.
oakwhiz 13y ago
Many crypto algorithms depend on good random numbers. Even if generating a key using a poor RNG is not a problem, some protocols create nonces which must be randomly selected or the security of the algorithm is greatly compromised. I'm not totally sure as to which algorithms fit this definition but some suggestions might be DSA/ECDSA, Diffie-Hellman, SRP, etc.

by Osmium 13y ago

mistercow 13y ago

>That said, I agree that you still shouldn't use it in a production environment! I wonder though. There's a possibility that you'll screw something up and miss it during testing, but I've also seen some scary analyses of expensive off the shelf RNG hardware. I'd say that if you're in a position of highly restricted capital that requires generation of tons and tons of secure random numbers, the ugly truth is that an open source DIY solution for generating your own entropy (especially if you can use multiple designs that are separately tested) might be safer than dumping your limited resources on proprietary unknowns.

oakwhiz 13y ago

Many crypto algorithms depend on good random numbers. Even if generating a key using a poor RNG is not a problem, some protocols create nonces which must be randomly selected or the security of the algorithm is greatly compromised. I'm not totally sure as to which algorithms fit this definition but some suggestions might be DSA/ECDSA, Diffie-Hellman, SRP, etc.