Eight Bits of Trust: How eMudhra Intermediate CAs Generated Single-Byte Private Keys (d=4) and Broke Global TLS
Eight eMudhra intermediate Certificate Authorities trusted by Mozilla, Google, Apple, and Microsoft root stores used single-byte P-384 private keys (d ≤ 255), allowing anyone on earth to recover CA private keys in milliseconds and forge trusted TLS/code-signing certificates.
In late October 2026, security researchers disclosed an unprecedented cryptographic failure in global Public Key Infrastructure (PKI): eight intermediate Certificate Authorities operated by eMudhra—and cross-signed by Sectigo's ubiquitous AAA Certificate Services root—were generated with trivial, single-byte private keys on the NIST P-384 elliptic curve. With private keys literally equal to small integers like 4, 56, and 115, anyone possessing the public certificates could recover the private signing keys in under a second. In response to global distrust by Apple, Google, Microsoft, and Mozilla, eMudhra announced its complete exit from the global SSL/TLS certificate business.