The developers of Tor, work on the ability to data traffic so as to mask that this appears to be from a different protocol. This should allow Tor traffic is less bothered by aggressive filters.
The method is by Tor described as obfsproxy, or an obfuscated proxy. Using such a Tor-proxy is it possible to have the data stream to manipulate. At Forbes gives Tor developer Andrew Lewman the example of an obfsproxy that an ssl-encrypted data stream to appear on a chat session, according to the xmpp protocol. This may result in aggressive filtration methods like deep packet inspection are bypassed.
The obsproxy-method in Tor is still experimental and would be a stream still insufficiently able to adapt to this in a reliable way, completely unrecognizable. Also, only connections that use tls, ssl, and socks protocol is supported, but the developers aim to also http and other common protocols to support.
Despite the alpha-status of obfsproxy, the Tor developers, the positive responses from, among others, Iran. In this country has the regime not only ip-blockades set up, but since recently also a blockade on all ssl and tls traffic is made. By obfsproxy to activate can Iranian internet users are still websites such as Gmail and Hotmail to achieve because the encrypted data is masked.