[libre-riscv-dev] buffered pipeline

[Jacob Lifshay]

On Wed, Mar 20, 2019 at 10:24 PM Luke Kenneth Casson Leighton <lkcl at lkcl.net>
wrote:

> On Thu, Mar 21, 2019 at 4:41 AM Jacob Lifshay <programmerjake at gmail.com>
> wrote:
> >
> > I'm building an RC4 random number source for simulation since it's a very
> > good source of random numbers (being designed as a stream cipher and all)
>
>  :)  weaknesses were discovered several years ago:
>
> https://threatpost.com/attack-exploits-weakness-rc4-cipher-decrypt-user-sessions-031413/77628/
>
> > I can't just use the preexisting random() function because the state is
> > shared.
>
>  ? que? you've lost me.  can you clarify: are you saying that you're
> concerned that the python random library does not have sufficient
> entropy?
>
I'm concerned that we won't be able to have multiple independently
advanceable sources of exactly reproducible pseudo-random numbers that can
be used on a fpga for testing.

>
> > I thought we might want a synthesizable source of
> > non-cryptographically secure random numbers later anyway.
>
NON-cryptographic. I know RC4 is essentially broken as a crypto primitive,
I'm just using it because it is close enough to a perfect source of
randomness for simulation and testing purposes, and it's really simple.
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Jacob