The short version
- eMudhra announced it is withdrawing from the global SSL/TLS certificate business following the discovery of eight intermediate certificates with critically weak private keys.
- Researchers found that the defective keys contained only three to eight bits of entropy, allowing anyone to generate trusted credentials for any website or server in milliseconds.
- Company leadership cited rising compliance costs and low revenue contribution as primary drivers for the exit, while acknowledging a procedural flaw during a key generation ceremony caused the security breach.
eMudhra Limited, an Indian certificate authority, has announced it will cease operations in the TLS certificate business. The decision follows a significant security incident in which the company issued eight intermediate certificates containing private encryption keys so weak that they could be trivially compromised. This development marks a sharp contraction for a firm that had previously played a role in securing internet communications, now stepping back from a sector where trust is paramount.
The vulnerability was identified by researchers who discovered that the private keys associated with these intermediate certificates possessed negligible entropy. While standard NIST P-384 elliptic curve cryptography keys are designed to contain approximately 384 bits of randomness, creating a vast number of possible combinations, the compromised keys ranged from just three to eight bits in size. The specific values for these defective keys were identified as 4, 56, 66, 115, 155, 156, 230, and 237. This extreme weakness meant that an attacker could crack the encryption in milliseconds.
The implications of such weak keys are severe for internet security infrastructure. Because these intermediate certificates were trusted by major web browsers and numerous other systems, including email servers, IoT devices, and various software containers, anyone who cracked the keys could generate valid TLS certificates for any domain. This capability would allow malicious actors to impersonate legitimate websites or intercept secure communications without detection by standard security protocols.
In response to the discovery, browser manufacturers acted quickly to block certificates issued using these compromised intermediate credentials. The action was taken within a day or two of the vulnerability becoming public knowledge. This rapid response helped mitigate immediate risks but underscored the fragility of the certificate authority ecosystem when foundational trust elements are breached. eMudhra also faced the potential loss of its status within the CA/Browser Forum, the industry body that governs admission to the TLS certificate program.
eMudhra provided a technical explanation for how such a critical error occurred. The company stated that the certificates were created during a Key Generation Ceremony held on April 30, 2025, using FIPS 140-2 Level 3 Hardware Security Modules. These dedicated devices are designed to store sensitive cryptographic data securely and are typically isolated from general networks. However, a flaw in the ceremony script caused a wrap/unwrap process to produce a second set of weak keys alongside the intended strong ones.
The company detailed that an approved deviation to their usual procedure was introduced to test the key transfer mechanism for export purposes. A coding error resulted in the creation of weaker keys on the hardware modules. Due to similar labeling, these defective keys were mistakenly used to create certificate signing requests and were subsequently signed by eMudhra’s root certificate. The flawed keys were also sent to Sectigo, another certificate authority, for cross-signing, further propagating the vulnerability.
Beyond the technical failure, eMudhra cited broader business factors in its decision to exit the market. V. Srinivasan, the company’s chairman, noted that the TLS certificate segment generates only one percent of the firm’s total revenue. He pointed to increasing costs and complexities associated with compliance requirements as significant burdens. Additionally, the rise of organizations providing free TLS certificates has reduced the return on investment for paid services, making the business less viable compared to other products offered by the company.
The company also addressed the public reaction to the incident, stating that social media amplification brought scrutiny disproportionate to the segment’s role in their overall business. Despite this perspective, the board concluded that withdrawing from the global SSL/TLS market was the right decision for shareholders. eMudhra indicated it is working to establish the root cause of the code flaws and process gaps, with plans to reverify every key ceremony conducted over the following week.
Sources behind this briefing
Go to the original reporting
- Ars Technica↗Disgraced eMudhra drops out of TLS business after using cert private key of 4
