I've factored the RSA keys of a Certificate Authority from the 90s

The author factored two 512-bit RSA root certificates from the defunct Canadian CA E-Certify that were shipped with Netscape 4.51 in 1999, using CADO-NFS on a Ryzen 9 5950X, taking 32 and 29 hours respectively. The resulting private keys and a custom TLS server are publicly available for recreating the ancient certificates, though they only work with legacy Netscape clients.