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

Security researcher Matthew McPherrin has successfully factored the 512-bit RSA private keys of two Certificate Authorities (CAs) from the late 1990s, E-Certify. These keys were used for SSL and S/MIME in Netscape 4.51, a browser version that shipped over two decades ago. McPherrin found these vulnerable root certificates within browser installers archived online and utilized the CADO-NFS factoring algorithm on his desktop computer, a process that took approximately 24 hours for each key. This demonstration highlights the significant security degradation of outdated cryptographic standards, as 512-bit RSA was already considered weak by 1999. The implications extend to the historical vulnerability of the early Web PKI, where less stringent standards were prevalent. While modern browsers are unaffected, this research serves as a stark reminder of how quickly cryptographic security can become obsolete, posing risks if legacy systems or data relying on these old keys were ever to be accessed.

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Matthew McPherrin's research successfully factored 512-bit RSA keys belonging to the Canadian Certificate Authority E-Certify. These keys were used in Netscape 4.51 for both SSL and S/MIME, underscoring the vulnerability of early web cryptography. The factoring process, executed on a standard desktop using CADO-NFS, took around 24 hours per key. This achievement demonstrates that cryptographic primitives considered secure in the past can become trivial to break with modern computing power, a critical lesson for understanding the evolution of digital security and the importance of regular key length upgrades.

The market implications, while not directly impacting current financial transactions, are significant from a historical and educational perspective. The successful factoring of these 1990s-era keys illustrates the risks associated with the early Web PKI, where standards were less mature. It highlights that any systems or data that might still rely on certificates issued by such compromised CAs, however unlikely, could be retroactively vulnerable. This research reinforces the industry's ongoing efforts to deprecate older, weaker cryptographic algorithms and key lengths, such as the ongoing transition away from 2048-bit RSA towards more quantum-resistant solutions.

Technically, the feat relies on the mathematical properties of RSA encryption, specifically the difficulty of factoring large prime numbers. By targeting significantly smaller key sizes (512-bit), McPherrin exploited the fact that factoring such numbers is computationally feasible on modern hardware. The use of CADO-NFS, a sophisticated algorithm for integer factorization, on a readily available Ryzen 9 5950X CPU, showcases the accessibility of breaking these older cryptographic standards. The subsequent demonstration of issuing valid certificates and serving them from a custom TLS server compatible with Netscape 4.51 further validates the compromise.

Looking ahead, this research prompts continued scrutiny of archived or legacy cryptographic material. It suggests that other small RSA keys from similar eras, particularly those found in older browser distributions or embedded systems, could potentially be factored. The next steps would involve identifying other similar vulnerabilities in archived root stores or older software implementations. Furthermore, this serves as a cautionary tale, emphasizing the need for continuous cryptographic agility and proactive migration to stronger, future-proof encryption standards to mitigate evolving threats, including those from potential quantum computing advancements.

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Covered by: hackernews