# Eight eMudhra certificate keys found trivially weak, and browsers pull their trust

URL: https://upsc.help/current-affairs/2026-10-22/emudhra-weak-keys-browser-distrust/
Date: 22 October 2026 (2026-10-22)
Source: The Hindu, News
UPSC papers: GS3
Publisher: upsc.help (Pratidin), free and open-source UPSC Civil Services current affairs. Not affiliated with UPSC. Every fact was checked against the source reports by a separate review before publishing.

**In one line:** Eight intermediate certificates of eMudhra, an Indian certifying authority, had private keys smaller than 256, so browsers blocked them and Mozilla moved to distrust one of its roots.

Eight intermediate certificates issued under eMudhra, a Bengaluru-based certifying authority (CA), were found to have private keys so weak that anyone could recover them. Mozilla received the report from an external researcher, forwarded by the Chrome Root Program, on 17 October 2026, and independently recovered the keys within hours. The keys were P-384 elliptic-curve keys, which should be random 384-bit numbers; each of the eight was an integer below 256, and one was the number 4. Six of the certificates could sign website (TLS) certificates and were trusted by Chrome, Mozilla, Microsoft and Apple; two were code-signing intermediates trusted by Microsoft.

The response was quick. Mozilla blocked the certificates on 17 October through OneCRL, its revocation list, and Chrome acted the same day. eMudhra revoked all eight on 18 October, Apple added protections on 19 October and Microsoft on 20 October. Mozilla then announced the emergency removal of trust in eMudhra's emSign ECC Root CA - G3. eMudhra told Mozilla that a flaw in the code used during its key generation ceremony on 30 April 2025 created a second, weaker set of keys that was used by mistake. It stopped issuing certificates from its G3 intermediates and estimated that about 30,000 certificates would need to move to another root.

The risk was that an attacker could issue fraudulent HTTPS certificates for websites they do not control. eMudhra said that, according to Certificate Transparency records, only one affected intermediate was in production, and that its Indian digital signature certificate and eSign services were working normally. In India, the Controller of Certifying Authorities (CCA) licenses CAs under the Information Technology Act, 2000; eMudhra is one of them, and the UIDAI website lists it as its certificate issuer. Researchers noted that CERT-In and the CCA had not issued public statements by 21 October, and experts warned that rarely updated devices may keep trusting the revoked certificates.

## Prelims facts

- Eight eMudhra intermediate certificates had P-384 private keys smaller than 256, recoverable by trying at most 256 values.
- Six were website (TLS) intermediates trusted by Chrome, Mozilla, Microsoft and Apple; two were code-signing intermediates trusted by Microsoft.
- Mozilla and Chrome blocked them on 17 October 2026; eMudhra revoked them on 18 October, and Mozilla moved to distrust the emSign ECC Root CA - G3.
- In India, certifying authorities are licensed by the Controller of Certifying Authorities, appointed under Section 17 of the IT Act, 2000.

## Quick recall

- **How many eMudhra intermediate certificates had compromised keys?** Eight: six for websites (TLS) and two for code signing.
- **What was wrong with the eMudhra keys?** They were integers below 256 (one was 4) instead of random 384-bit numbers.
- **When did Mozilla receive the report?** 17 October 2026; Mozilla and Chrome blocked the certificates that day.
- **Which eMudhra root did Mozilla move to distrust?** emSign ECC Root CA - G3.
- **Under which section of the IT Act is the CCA appointed?** Section 17 of the Information Technology Act, 2000.
- **Under which provision was the Root Certifying Authority of India set up?** Section 18(b) of the IT Act, 2000.
- **What does Section 3 of the IT Act, 2000 do?** Gives legal sanctity to digital signatures (authentication of electronic records).
- **CERT-In's 2022 reporting deadline for cyber incidents?** Six hours from noticing the incident, under directions of 28 April 2022 (Section 70B(6)).

## Prelims practice question

With reference to the Controller of Certifying Authorities (CCA) in India, consider the following statements:
1. It is appointed under the Information Technology Act, 2000.
2. It set up the Root Certifying Authority of India, which signs the public keys of licensed certifying authorities.
3. It functions under the Ministry of Home Affairs.
Which of the statements given above are correct?

(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Answer: (a) 1 and 2 only. Statement 1 is correct: the CCA is appointed under Section 17 of the IT Act, 2000. Statement 2 is correct: the Root Certifying Authority of India was set up under Section 18(b) and signs CAs' public keys. Statement 3 is incorrect: the CCA is under the Ministry of Electronics and Information Technology.

## UPSC previous-year questions this connects to

- UPSC Prelims 2019, Prelims: Consider the following statements: A digital signature is 1. an electronic record that identifies the certifying authority issuing it 2. used to serve as a proof of identity of an individual to access information or server on Internet 3. an electronic method of signing an electronic document and ensuring that the original content is unchanged Which of the statements given above is/are correct? (a) 1 only (b) 2 and 3 only (c) 3 only (d) 1, 2 and 3 (https://upsc.help/pyq/prelims/#q349)
- UPSC Mains 2022, GS3: What are the different elements of cyber security? Keeping in view the challenges in cyber security, examine the extent to which India has successfully developed a comprehensive National Cyber Security Strategy. (https://upsc.help/pyq/q343-different-elements-cyber-security-keeping-view-challenges/)
  How to use this story in the answer: Use the eMudhra case to show that trust infrastructure is an element of cyber security and that India's incident communication remains weak.

## Mains practice question

What is the role of certifying authorities in securing digital transactions? In the light of the recent compromise of certificate keys at an Indian certifying authority, suggest measures to strengthen India's digital trust infrastructure. (250 words)

### Model answer

Certifying authorities (CAs) vouch that a public key belongs to a particular website or person. In October 2026, eight intermediate certificates of eMudhra, an Indian CA, were found to have private keys smaller than 256, recoverable by anyone.

## Role of certifying authorities
- **Identity:** they bind identities to public keys through certificates, making HTTPS, code signing and digital signatures trustworthy.
- **Legal basis in India:** Section 3 of the IT Act, 2000 recognises digital signatures; the Controller of Certifying Authorities (Section 17) licenses CAs, and the Root Certifying Authority of India (Section 18(b)) signs their keys.
- **E-governance:** digital signature certificates and eSign support filings and authentication; the UIDAI website lists eMudhra as its certificate issuer.

## What the eMudhra case reveals
- **Process failure:** eMudhra blamed flawed key generation code; a P-384 key should be a random 384-bit number.
- **Global dependence:** browser root programmes, not Indian regulators, acted first: Mozilla and Chrome on 17 October 2026, Apple and Microsoft by 20 October.
- **Long tail:** rarely updated devices may keep trusting revoked certificates.
- **Communication gap:** CERT-In and the CCA had issued no public statement by 21 October.

## Measures
- Independent audits of key ceremonies, with keys generated inside certified hardware security modules.
- Mandatory, prompt public disclosure of CA incidents, coordinated by CERT-In and the CCA.
- Trust-store update rules for government systems and connected devices.
- Use of Certificate Transparency logs to detect misissued certificates early.

Digital trust is only as strong as its weakest key, so India's CA ecosystem needs audit, transparency and fast response.

## The basics

## Why this matters

Every time a browser shows a padlock, it is trusting a chain of digital certificates. If the secret key behind one link in that chain leaks, anyone holding it can issue certificates that browsers accept, and so pretend to be a bank, a ministry or an email provider. In October 2026 eight such keys belonging to eMudhra, a Bengaluru-based certifying authority, were found to be so weak that they could be guessed in moments.

## How the chain of trust works

The system is called Public key infrastructure. Browsers ship with a short list of trusted root certificates. Roots sign intermediate certificates, and intermediates sign the certificates that websites present. A certificate is only as safe as the Private key that signs it.

## What went wrong

The eight keys were P-384 keys, a type of elliptic-curve key that should be a random 384-bit number. Instead, each was an integer below 256. One was the number 4. Anyone could recover such a key by trying at most 256 values.

## How the system responded

Mozilla received the report on 17 October 2026 and blocked the certificates the same day through OneCRL, its revocation list. Chrome also acted on 17 October, eMudhra revoked the eight certificates on 18 October, Apple followed on 19 October and Microsoft on 20 October. Mozilla then announced the emergency removal of trust in eMudhra's emSign ECC Root CA - G3.

## The Indian frame

In India, digital signatures get legal force from the Information Technology Act, 2000, and certifying authorities are licensed by the Controller of Certifying Authorities. The weakness raised a wider Cyber security question: how many systems that rarely update their trust lists will keep accepting the bad certificates.

## Sources

- https://bugzilla.mozilla.org/show_bug.cgi?id=2083449
- https://www.bleepingcomputer.com/news/security/mozilla-google-apple-block-compromised-emudhra-ca-certificates/
- https://www.theregister.com/security/2026/10/20/indian-certification-authority-emudhras-private-keys-compromised-one-of-them-was-the-number-4/5304312
- https://www.medianama.com/2026/10/223-emudhra-security-flaw-weak-private-keys-explained/
- https://cca.gov.in/about.html
- https://trilegal.com/knowledge-repository/2022-cert-in-directions-on-reporting-cyber-incidents/