I've factored the RSA keys of a Certificate Authority from the 90s
Security researcher factored two 512-bit RSA root CA keys from defunct 1990s certificate authority E-Certify using CADO-NFS on a desktop in roughly 30 hours each.
A researcher extracted legacy root certificates from archived Netscape and Internet Explorer installers, identifying two 512-bit RSA roots shipped with Netscape 4.51 in 1999 by the defunct Canadian CA E-Certify. Using CADO-NFS on a Ryzen 9 5950X desktop, the keys were factored in 32 and 29 hours respectively, allowing private key reconstruction. The work comes shortly after RSA-260 (862-bit) was factored, the largest known factorization to date. The researcher also built a legacy TLS server and published keys and tools on GitHub.
- Two 512-bit E-Certify root keys factored on a desktop using CADO-NFS
- Roots shipped with Netscape 4.51 in 1999 and removed by 2002
- RSA-260 (862-bit) factorization recently reported as the largest known
- Private keys and legacy TLS tooling released publicly on GitHub
- Highlights risks of weak small-key RSA in early Web PKI
- Products
- CADO-NFSNetscape 4.51
From the original article
4 min read at mcpherrin.caI’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
By ahlCVA · mcpherrin.ca
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