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tech 8 September 2026

I've Factored the RSA Keys of a 90s Certificate Authority

Dive into the intriguing history of 90s RSA keys and discover how once-robust technologies are now vulnerable.

Article inspired by the original source
I've factored the RSA keys of a Certificate Authority from the 90s ↗ mcpherrin.ca

Introduction

RSA cryptography is at the heart of modern digital security. However, what was once considered an impregnable fortress can now be a house of straw. By exploring the archives of 90s certificate authorities (CAs), we discover how computing advances have rendered some security practices obsolete.

Historical Context

In the 90s, Web PKI was in its infancy. Browsers like Netscape and Internet Explorer began integrating SSL support, crucial for the development of e-commerce. At that time, 512-bit RSA keys were common, although already vulnerable. In 1999, Netscape 4.51 shipped with a 512-bit CA, a key size now considered easy to factor.

The Factoring Adventure

Matthew McPherrin successfully set out to factor these old keys. Using a modern desktop computer, a Ryzen 9 5950X, he was able to factor a 512-bit RSA key in about 32 hours. This achievement not only demonstrates the power of current machines but also the rapidity with which cryptography can become obsolete.

The Quantum Computer Threat

Even 2048-bit keys, today's standard, are threatened by the development of quantum computers. These machines could theoretically solve factoring problems much faster than classical computers, posing a major risk to current cryptographic systems.

Lessons Learned

This factoring project highlights the importance of constantly updating security standards. Companies must be proactive, adopting more robust cryptography technologies and staying informed about new threats.

Conclusion

The story of 90s RSA keys is a valuable lesson on the evolution of digital security. In a world where technology progresses at a breakneck pace, it is essential never to rest on your laurels.

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References

  • McPherrin, M. (2026). RSA Factoring Challenge. Retrieved from [URL]
RSA cryptographie sécurité quantique factoring
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