Re: [Cfrg] Curve manipulation, revisited

Benjamin Black <b@b3k.us> Mon, 29 December 2014 21:48 UTC

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From: Benjamin Black <b@b3k.us>
Date: Mon, 29 Dec 2014 13:47:36 -0800
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To: Watson Ladd <watsonbladd@gmail.com>
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Subject: Re: [Cfrg] Curve manipulation, revisited
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On Mon, Dec 29, 2014 at 12:04 PM, Watson Ladd <watsonbladd@gmail.com>; wrote:

>
> You are correct, I meant 2^384-big vs. 2^383-31 or 2^389-21. But
> neither of these are as good as 2^448-2^224-1: there are no good
> choices of prime around 2^384. I and Mike Hamburg gave 2^389-21 a try,
> and we couldn't compare to your listed numbers for 2^384-big directly:
> I think we concluded they were in the same ballpark. We can get a lot
> more security for very little drop in speed with 2^448-2^224-1.
>
>
How far from 2^384 did you look? I think it would be useful to the group to
know which candidates were considered and why they were rejected.


b