Re: [PATCH] API for true Random Number Generators to add entropy (2.6.11)

[Jeff Garzik <jgarzik@pobox.com>]

Bill Davidsen wrote:
> Herbert Xu wrote:
> 
>> You missed the point.  This has nothing to do with the crypto API.
>> Jeff is saying that if this is disabled by default, then only a few
>> users will enable it and therefore use this API.
>>
>> Since we can't afford to enable it by default as hardware RNG may
>> fail which can lead to catastrophic consequences, there is no point
>> for this API at all.
> 
> 
> Wait a minute, if it fails the system drops back to software, which is 
> not as good in a pedantic analysis, but perhaps falls a good bit short 
> of "catastrophic consequences" as most people would characterize that 
> phrase. And more to the point, now that many CPUs and chipsets are the 
> RNG of choice, what is the actual probability of a failure of the RNG 
> leaving a functional system (that's a real question seeking response 
> from someone who has some actual data).

As I've said, in the past the Intel RNGs in particular -have- failed, 
but the rest of the system keeps on working just fine.

It probably depends on the hardware implementation; I think the Intel 
RNG was based on a thermal diode, or somesuch.

In the cases where an RNG has failed in the past, the system has worked 
as expected:  rngd stopped feeding data into the entropy pool.

If the VIA RNG (on-CPU) fails, that's probably indicative of a larger 
problem, though.

	Jeff