[Cado-nfs-discuss] 回复: DLP problem

Pierrick Gaudry pierrick.gaudry at loria.fr
Mon Dec 3 07:39:32 CET 2018


Hi David,

Sorry, but at the moment we don't have parameter files for DLP in all
sizes. We are currently experimenting with many variants and since tuning
parameters is a long job, we'll do it only when we are reasonably
confident that we won't have to do it again in a few months.

Regards,
Pierrick

On Sat, Dec 01, 2018 at 11:24:03PM +0800, ┃ Be Happy 、╯ wrote:
> Dear Pierrick,
> 
> 
> Thank you so much for your helping. I have solve the problem and successfully finish part of my homework. But now I meet a new problem, I can't solve the problem when p is 132-digit. I don't know how to build .hint file and params file. In fact I successfully used 100-digit file to solve a 78-digit problem. But now I am trapped. I am wondering if you could help me?
> 
> 
> Best regards,
> David Wu
> 
> 
> 
> 
> 
> 
> 
> 
> ------------------ 原始邮件 ------------------
> 发件人: "Pierrick Gaudry"<pierrick.gaudry at loria.fr>;
> 发送时间: 2018年12月1日(星期六) 晚上9:43
> 收件人: "┃ Be Happy 、╯"<davidwu2538 at qq.com>;
> 抄送: "cado-nfs-discuss-owner"<cado-nfs-discuss-owner at lists.gforge.inria.fr>; 
> 主题: Re: DLP problem
> 
> 
> 
> Dear David,
> 
> Could you have a look at the following thread on this mailing-list :
>    https://lists.gforge.inria.fr/pipermail/cado-nfs-discuss/2018-November/000939.html
> 
> It seems that this answers your question.
> 
> Best regards,
> Pierrick
> 
> On Sat, Dec 01, 2018 at 08:12:36AM +0800, ┃ Be Happy 、╯ wrote:
> > I am not sure if I did this right, but I met a problem and I can't solve it.
> > 
> > I use the example you give in README.dlp:
> > $ ./cado-nfs.py -dlp -ell 101538509534246169632617439 target=92800609832959449330691138186 191907783019725260605646959711
> > and the answer is:
> > p = 191907783019725260605646959711
> > ell = 101538509534246169632617439
> > log2 = 35338258800684599318721749
> > log3 = 62614277196775799921779143
> > The other logarithms of the factor base elements are in /tmp/cado.yliqctwz/p30.dlog
> > target = 92800609832959449330691138186
> > log(target) = 32359472153599817010011705
> > 
> > For the discrete logarithm of primitive root 2 (i.e. g=2), only log (target)/log2 mod ell, and the answer is
> > 5995158352878681776097204.
> > 
> > But when I want to check out if the answer is right, so I compute
> > 2^5995158352878681776097204 (mod 191907783019725260605646959711)
> > I get 36195192389531979502867378706 and it's obviously not target.
> > 
> > 
> > I and my classmate have the same problem and I don't know what is wrong.
> > 
> > 
> > and I don't know how to build a file if I want to compute a 78-digit p, could you please help me?
> > 
> > 
> > Cheers!
> > 
> > 
> > David Wu


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