I've factored the RSA keys of a Certificate Authority from the 90s
Points and comments are a snapshot, not live.
Two 512-bit RSA keys from 1999 Netscape root CAs were factored on a desktop computer.
The author factored two 512-bit RSA keys from E-Certify root certificates shipped in Netscape 4.51 in 1999. Using CADO-NFS on a Ryzen 9 5950X desktop, factoring took 32 and 29 hours respectively. The resulting private keys can issue certificates for Netscape 4.51 with a pre-2003 system clock. The author also reproduced a VeriSign test CA key in about an hour on a GPU cluster. SSL Labs gives the resulting test site an F rating.
What commenters are saying
Commenters note that factoring 512-bit RSA is a weekend project for consumer hardware but a very different story for 1024-bit or 2048-bit keys. Estimates range from 2,000 GPU-years for 1024-bit to millions of years for 2048-bit, with the GNFS algorithm's memory requirements being the bottleneck. A subthread discusses whether governments record traffic today for later decryption, with skepticism that decade-old activist traffic holds much value. One commenter praises the SSL Labs F rating as the punchline.