[openssl-dev] Work on a new RNG for OpenSSL

[Paul Dale]

Uri wrote:
>>    It might also use things like RDRAND / RDSEED which we don't trust.
> ...
>  From cryptography point of view, it cannot hurt, but may help a lot    

There is a scenario where it does hurt: https://www.lvh.io/posts/2013/10/thoughts-on-rdrand-in-linux.html

This attack wouldn't be difficult to implement given all the out of order execution and look ahead that CPUs do.   It requires a compromised RDRAND instruction changing the behaviour of a subsequent XOR into a copy.  Not only would it not be producing random bits but it would remove any randomness from the bits you already have.


Pauli
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Dr Paul Dale | Cryptographer | Network Security & Encryption 
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Oracle Australia