Web API to check if using Tor

[fpietrosanti]

Certain client-side Javascript application on the internet require to know if they are using Tor or not.

Currently Tor2web have the awareness about the existing Tor Exit Relay due to feature #10 .

This feature is to implement a publicly available Web API, that allow a third party Javascript client, to request if is coming from Tor or not.

The API must be available for query via CORS, so appropriate header to allow cross-domain query must be provided.

Cc @hellais, @evilaliv3, @vecna .

[fpietrosanti]

This functionality may allow to easily replace TorCheck/PrivacyBadge feature, by incorporating that functionality built-in within Tor2web network.

The Web API, must respond to any kind of Tor Hidden Service URL in HTTPS, regardless if it's blocked or not and regardless if it exists or not. This is in order to improve plausible deniability client-side.

The proposed use for this API has been described on GLClient ticket "New PrivacyBadge Concept" at https://github.com/globaleaks/GLClient/issues/2

[fpietrosanti]

Closed, because we agreed that's not required and overlapping with https://trac.torproject.org/projects/tor/ticket/6546