"Legion" also claimed to hack Twitter handles of Congress Party and its Vice President Rahul Gandhi earlier this month, bringing the hacking threat close to more Indian leaders and celebrities who are on Twitter.
In a tweet, "Legion" -- whose country of origin is yet to be known -- asked people to support them "@sigaint.org".
Let us know what Sigaint is and how all this works.
According to the Sigaint website, it is a "darknet email service that allows you to send and receive email without revealing your location or identity". Sigaint claims to provide email IDs which are secure on TOR browser.
"We provide this service to help journalists and activists combat the dragnet surveillance that exists on the internet today. Even if you aren't in conflict with the state or anyone in particular, you as a human being deserve privacy," it read.
The website is hosted on "onion.to" but the service claims it does not host the Sigaint content.
"We are simply a conduit connecting internet users to content hosted inside the Tor network. onion.to does not provide any anonymity. You are strongly advised to download the Tor Browser Bundle and access this content over Tor," it said.
Famous among individuals and businesses who want to remain anonymous online, Tor is a free software and an open network that helps users defend against traffic analysis - "a form of network surveillance that threatens personal freedom and privacy, confidential business activities and relationships, and state security".
Sigaint also claims that emails created by the network can only be accessed by downloading TOR browser.
If we look at the name "Legion," there was a famous US-based hacker group called "Legion of Doom" (LOD) founded by Lex Luthor which was active in late 1990s and early 2000. LOD is ranked as one of the most influential hacking groups in the history of technology.
We still do not know if "Legion" is inspired by LOD but it looks well versed with the dark world of web and is using whatever it can to launch cyber attacks anywhere in the world, including in India.