Google has blocked several digital certificates issued in India that could have been used to make bogus websites appear to be run by the Web giant.

The digital certificates were issued by the National Informatics Centre (NIC), part of India’s Ministry of Communications and Information Technology that handles e-government projects, wrote Adam Langley, a Google security engineer, on Tuesday.

How the bogus certificates were issued by NIC is under investigation, Langley wrote. Users are not believed to have been affected.

“We have no indication of widespread abuse, and we are not suggesting that people change passwords,” he wrote.

Web browsers check a domain’s digital certificate to verify it actually belongs to the entity that claims it. The certificate is also used to encrypt communications between a computer and the domain using SSL/TLS (Secure Sockets Layer/Transport Layer Security).

The certificates are issued by authorized authorities. Hackers have occasionally attacked those authorities and created valid digital certificates for illegitimate domains they’ve created, which pass a security check. If users were lured to the fraudulent website, an attacker could decrypt their data traffic.

Security experts have long warned of the problems with wrongly issued digital certificates. To combat the problem, Google has pushed its Certificate Transparency project, which is aimed at quickly detecting SSL certificates that have been mistakenly issued or acquired by hackers.

The certificates were revoked on July 3, a day after Google’s discovery of the problem, by another ministry agency, the Indian Controller of Certifying Authorities (India CCA), which regulates Certificate Authorities that issue digital certificates in India, Langley wrote.

Indian officials could not be immediately reached for comment.

The NIC held intermediate digital certificates, which were trusted by the Indian CCA, Langley wrote. Indian CCA certificates are trusted by most programs runnings on Windows, including Internet Explorer and Chrome, Langley wrote.

Firefox is not affected because it uses its own list of trusted certificates that doesn’t include the Indian CCA ones, he wrote. Also, Chrome, Chrome OS, Android, iOS and OS X are not affected.

Chrome running on Windows would not have been fooled by the certificates due to a security measure Google uses called public-key pinning, he wrote. Google has also updated Chrome’s CRLSet, a list of certificates that are trusted.