[gnutls-dev] Re: Feature request: not really random session keys
fw at deneb.enyo.de
Mon Jan 30 17:11:30 CET 2006
* Simon Josefsson:
> Florian Weimer <fw at deneb.enyo.de> writes:
>> I tracked this down to the generation of the RSA_EXPORT key. In this
>> case, bits from /dev/random are used, even though the generated key is
>> horribly insecure anyway.
>> Wouldn't it make sense to use only STRONG_RANDOM in this case, and not
> Perhaps. But doesn't this happen for non-RSA_EXPORT keys too? We
> wouldn't want to make that change there.
I think you'd need to pass an additional flag, yes. It's certainly
not a two-line change, and I can understand if you don't want to make
it for such a silly feature.
> It seems better to fix Exim here.
Even if we follow the advice in your other message, a busy mail server
will deplete the pool at an alarming rate (each TLS-enabled SMTP
connection consumes 600 bytes from the kernel pool -- which can only
store 4096 bits). This means that gathering the required true
randomness may take a long time. We'll see if it's still acceptable,
or if the randomness is distributed so unfairly that it won't work.
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