eMudhra exits TLS business after issuing weak keys — Ars Technica

Indian certificate authority eMudhra has announced its exit from the global SSL/TLS business following an incident involving eight intermediate certificates whose private keys were found to be critically weak. As Ars Technica reports, these keys could be guessed in milliseconds and used to create certificates for any websites or mail servers.

eMudhra Limited Chairman V. Srinivasan explained the decision by rising costs and the complexity of meeting requirements. According to him, the SSL/TLS segment generated only 1% of the company’s revenue, while free TLS certificates offered by other organizations reduced the profitability of this business.

The keys had 3 to 8 bits of entropy

Researchers found that the eight compromised keys had only 3 to 8 bits of entropy, although NIST P-384 cryptographic standard keys should contain approximately 384 bits of entropy. The values of the discovered private keys were 4, 56, 66, 115, 155, 156, 230, and 237. For the strongest of the defective keys, there were no more than 256 possible variants.

More current news is available on the UA.News Telegram channel Telegram.

Browser vendors blocked certificates issued using these intermediate certificates within one to two days after their discovery. At the same time, devices and software that use their own copies of root certificates may need more time for such blocking. Some embedded devices may not receive the relevant update at all.

Error during key generation

eMudhra said that the certificates were created on April 30, 2025, during a key generation procedure using FIPS 140-2 Level 3 hardware security modules. According to the company’s preliminary version, an error in the procedure script during a key wrapping and unwrapping operation caused a second set of weak keys to appear alongside the original ones. The company said it continues to determine the root cause.

On the Mozilla Bugzilla forum, eMudhra said the weak keys were mistakenly used to create a certificate signing request because of similar key names. The company also acknowledged human errors at several stages of the process and said it intends to recheck all key generation ceremonies that were conducted.