Sigaint (sigaintevyh2rzvw.onion) is one of the largest web email services on the TOR network. The service has run for years despite the attempt of law enforcement agencies of deanonymizing its users. Sigaint is constantly under attack of Government agencies, in April 2015 its administrator warned the users of cyber attacks alleged launched by law enforcement agency who tried to hack the service. A Sigaint user is offering 20k to get back it emails.”]
Source: https://securityaffairs.co/wordpress/56808/deep-web/sigaint-outage-mystery.html