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

I’ve factored the RSA keys of a Certificate Authority... … from the 90s. I’ve been thinking about the security of RSA lately. RSA’s cryptography relies on the difficulty of factoring a large semiprime number, but what “large” means is an interesting question. The Web PKI deprecated 1024-bit RSA over a decade ago, and while I don’t know of anyone factoring a key of that size, it’s within the realm ...