That's a good point. I've added to the post. It's simple enough I'd expect anyone who wants to do it can follow the docs from CADO-NFS, which are very good, but

That's a good point. I've added to the post. It's simple enough I'd expect anyone who wants to do it can follow the docs from CADO-NFS, which are very good, but I can write it down explicitly. Install CADO-NFS per upstream directions. Get the number you want to factor. I just did this in a python repl, something like: from cryptography import x509 f = open("gold-server.pem", "rb").read() print(x509.load_pem_x509_certificate(f).public_key().public_numbers().n) That gets you the `n` to factor - The big number below. Then pass it to CADO-NFS. The full invocation for the server root was: ./cado-nfs.py 10754123440737946604182274398563307850262685121187325065132187145895199633213947273310647001521000121802425390193123548314361970563322281259804690831526167 -t 32 --workdir /data/cert1 All run in a tmux to keep it alive for the few days, of course.