hermann on Sun, 02 Jul 2023 08:33:23 +0200


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PARI/GP addprimes() and factor() completing cado-nfs.py factoring job


Until a few days ago factoring RSA numbers above 115 digits was a pain.
With my new 7600X CPU PC factoring RSA-100 with msieve dropped to only 1.5h.

But yesterday with parallel cado-nfs
https://github.com/cado-nfs/cado-nfs

RSA-100 got factored in <8min, and RSA-129 in 3:11:10h !
https://github.com/Hermann-SW/RSA_numbers_factored/blob/main/cado-nfs/README.md#cado-nfs


I had factorization dictionaries of p-1 and q-1 for up to RSA-220.
Now I am completing the 5 factored sofar without (RSA-230/232/768/240/250).

Unlike msieve, cado-nfs returns an unsorted list of prime factors only, without needed powers.


Factoring q-1 of RSA-230 returned this in 0:28:14h
2 5 64279 50683730684497957 17639078797309 690514165195709800287433291837488016671814279191657241584683922421815714039547

PARI/GP completes the job easily:

? \r RSA_numbers_factored
? [l,n,p,q]=rsa[21][1..4];
? #digits(q-1)
%18 = 115
? addprimes([2,5,64279,50683730684497957,17639078797309,690514165195709800287433291837488016671814279191657241584683922421815714039547]);
? factor(q-1)
%20 =
[ 2 2]

[ 5 2]

[ 64279 1]

[ 17639078797309 1]

[ 50683730684497957 1]

[690514165195709800287433291837488016671814279191657241584683922421815714039547 1]

?


Regards,

Hermann.