eMudhra CA compromise: eight “secret” keys, one was the number 4
In early October 2026, eMudhra, an Indian certificate authority licensed by the Controller of Certifying Authorities and trusted by every major browser, issued eight intermediate certificates whose private keys carried 3 to 8 bits of randomness. A real key of this class has about 2384 possible values. These eight are 4, 56, 66, 115, 155, 156, 230 and 237. Anyone holding them could mint valid certificates for any website on earth, and browsers would show the padlock and say nothing. The full consumer investigation, public statement and open letter live in this site's eMudhra section.
What we can state
| Fact | Basis | Status |
|---|---|---|
| Eight intermediates, guessable keys | Researcher “Wayne” proved key control on 17 Oct by signing taunts with each private key; Mozilla and Chrome bug trackers confirmed | confirmed |
| No evidence of misuse | Public certificate-transparency logs show no fraudulent issuance in the exposure window | absence of evidence, not proof of safety |
| Recovery, not accident | eMudhra's own account: keys moved to US/EU data centres under an “approved deviation”; re-signing done with broken keys instead of halting | process failure |
| India systems on the vendor | Our live TLS handshakes: UIDAI's website and GeM serve certificates from eMudhra chains; IDRBT (the RBI-established institute running the banking sector's CA) builds issuance on eMudhra's emCA platform | verified by us |
| Regulatory silence | No public statement from CCA India, RBI, MeitY or CERT-In as of 21 Oct 2026, while Mozilla and Chrome ran public incident processes | open |
What it means for consumers
For a window of days, anyone holding those keys on a network between you and your bank could impersonate the bank so well that your browser would certify the impostor. Updated Chrome, Firefox and Safari carry the fix; Signal, WhatsApp and WireGuard pin their own trust. The unfixable tail is old Android phones, routers, smart TVs, forgotten servers and unpatched tooling, and that tail is disproportionately Indian. We make no finding that anyone was intercepted. We say the conditions were met, and no Indian authority has told consumers otherwise.
What we demand
Our open letter to the Reserve Bank of India and MeitY, copied to CCA India, CERT-In and IDRBT, asks four things, numbered for answer:
- A public accounting from eMudhra, verified by an independent auditor, of every key that left its custody.
- A public incident report from IDRBT on banking-PKI exposure, given its issuance rides on eMudhra's emCA platform.
- Consumer remediation: explicit guidance from RBI and MeitY to banks and government services on trust-store updates, and notification duties where long-lived clients stay exposed.
- An independent, open and verifiable investigation of India's certificate ecosystem, with public audit trails. That standing is currently borrowed from foreign browser root programs.
Explore the full investigation
- Consumer guide: what happened, who is protected and exposed, do-this-today checklist, curated video explainers
- Public statement: the full sourced account, footnote by footnote
- Open letter: to RBI and MeitY, with a 14-day answer clock
- Corporate history: eMudhra's people, licence, listing, acquisitions and who profits