eMudhra Limited, an India-based certificate authority, is exiting the global SSL/TLS certificate business following a security incident in which the company issued eight intermediate credentials with private encryption keys so weak they could be cracked in milliseconds.
Chairman V. Srinivasan said the exit reflects business economics: rising compliance costs, the emergence of free certificate providers that undercut pricing, and the fact that SSL/TLS generated only 1 percent of eMudhra's revenue. The board determined that withdrawing from the segment was the right move for shareholders.
The catalyst was a discovery by researchers that eMudhra had issued certificates with private keys ranging from 3 to 8 bits—compared to the 384 bits required by standard NIST P-384 elliptic curve cryptography. The specific defective keys were 4, 56, 66, 115, 155, 156, 230, and 237. The strongest offered only 2^56 possible combinations, trivial for an attacker to brute-force. The weakest key—just 4—required no computation to discover.
An attacker with access to these compromised intermediate certificates could generate TLS credentials trusted by major browsers, email servers, IoT devices, Docker containers, and unmaintained Linux systems.
Browser makers blocked the certificates within one to two days of disclosure. eMudhra faced likely revocation of its certificate authority status by the CA/Browser Forum, the industry body that governs TLS participation.
The company traced the flaw to a Key Generation Ceremony on April 30, 2025, which used FIPS 140-2 Level 3 Hardware Security Modules. A defect in the wrap/unwrap step—the process that encrypts and decrypts keys within HSMs—produced a secondary set of weak keys alongside the intended strong ones. The weak keys were then published to browser root stores. eMudhra said it is still determining the precise root cause.
