Python Random Number Generator for OTP
Andy Isaacson
adi at hexapodia.org
Wed Jul 24 10:27:06 PDT 2013
On Tue, Jul 23, 2013 at 03:24:39PM -0700, Bill Stewart wrote:
> >> > Why not use /dev/random, instead of "ensuring you have entropy"
> >> /dev/random limits the output size to the estimated entropy. So
> >it has abysmal performance unless there are high performance
> >entropy sources available.
>
> This is for a one-time pad. Limiting the output size to the
> estimated entropy is a *requirement*. Abysmal performance is fine,
> because you're going to transfer the pad using a briefcase
> handcuffed to a courier's arm or some similarly high-cost
> high-latency physical distribution method, though if you've got a
> higher-performance entropy source, great.
My /dev/random generates a few hundred kilobytes a day. I exchange OTPs
on a SD card to a friend sitting across the table. I need to be able to
make a bigger pad than allowed by the horrifically overly conservative
entropy estimates provided by /dev/random.
-andy
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