Assessing Security of Certificates at Scale
Cisco researchers run Batch GCD factorization across 100M+ public X.509 certificates, recovering private RSA keys from low-entropy embedded devices.
Summary
Entropy Failures in Global Key Generation
Flawed pseudorandom number generators and entropy depletion during embedded device boot cycles produce RSA keys that share prime factors with other devices on the internet.
Scaling Batch Greatest Common Divisor (BGCD) Algorithms
David McGrew, Brandon Enright, and Andrew Chi develop high-performance multithreaded tools to run Batch GCD computations across more than 100 million public HTTPS certificates.
Factoring Moduli and Generating Private PEM Keys
Correlating public certificates harvested from active scanning and Certificate Transparency logs identified thousands of vulnerable RSA moduli, immediately computing their private keys.
Auditing and Remediating Weak Public Keys
The authors demonstrate automated certificate auditing pipelines, urging certificate authorities and hardware manufacturers to enforce automated pre-issuance GCD checks.
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