With the launch of a "national"—more censored—version of the Internet only a few weeks away in Iran, users are already reporting increasingly limited access to certain Web sites and Web security features. A number of Internet users in Iran have for the past few days reported difficulty connecting to Web sites housed on servers outside of that country, as well as blocked access to sites such as Google and Yahoo, and to any encrypted Internet traffic, according to Iran Media Program, a project of the Center for Global Communication Studies at the Annenberg School for Communication, University of Pennsylvania.

The timing coincides with potential protests to mark the first anniversary of the house arrest of lead opposition candidates Mir-Hossein Mousavi and Mehdi Karroubi. Or the shutdown, the exact source of which has not been made public, could be an effort to prevent protests on Saturday, the anniversary of the 1979 Islamic Revolution in Iran. (The Shah's regime collapsed on February 11 of that year; the country became an Islamic Republic on April 1.) Much speculation points to the Iranian government's desire to prevent protesters from organizing online as occurred with the Arab Spring last year on venues including Facebook and Twitter.

The Tor Project, a group that maintains the Tor system for enabling online anonymity, reported Friday that a number of Iranians are also having difficulty using Tor from inside Iran. The Iranian government appears to censoring online content by inspecting encrypted Internet traffic, selective blocking of other traffic, and some keyword filtering, according to the Tor Project, which was alerted to the problem when access to its own site was partially blocked.

This communications cut-off in Iran comes little more than a year after five of Egypt's major Internet service providers (ISPs) shut down their connections to the Internet. It is suspected that the ISPs were ordered offline by then-President Hosni Mubarak, who was looking to disrupt protest of his government. Mubarak was ousted shortly thereafter and is now on trial for allegedly ordering the killing of protesters.

Image of the June 2009 election protests in Iran courtesy of Hamed Saber, via Wikimedia Commons