About 40,000 Internet users in Iran used Tor until it was blocked by the government at the end of July. Only 25% of Tor users were able to access the network after this. Because it was a general block on all encrypted traffic, VPN services such as the IAPS Security VPN may also be affected.
Anonymity for Open Access
Tor has served the Internet users of Iran for years to give them open access to websites that the government has blocked. But since 2011, the government has eyed Tor with suspicion. Tor was used to promote Iran’s Green Movement. Bloggers, protesters and activists relied on Tor anonymity to protect them. Tor uses independently run servers to reroute traffic before it reaches its destination so that users cannot be tracked and identified. Tor also provides additional security by regularly monitors its network so government surveillance can be prevented.
Tor was the first to report on July 30 that its users in Iran were not able to get through. Tor investigated and reported the reason five days later. Andrew Lewman, Project Executive Director of Tor, said that the Iranian government was able to prevent access to the network by throttling any traffic that looked like it was using encryption. This is the challenge for anonymizing services, he said, because governments can easily tell the difference between traffic that uses encryption protocols from regular, unencrypted traffic. They can then easily filter this traffic out.
The pluggable transports of Tor were not blocked, however, and Tor announced that they could still be used to access the network. Since the blocking of all encrypted traffic would cause problems for VPN users as well, this solution may have been be the only way for Iranian Internet users to access restricted content from then end of July to the first week of August. Many of the top VPN services do use more secure private tunneling, however, which can prevent the government from detecting the encrypted traffic.
Frederic Jacobs, an Internet security researcher, says that the recent block on Tor in Iran can be a positive event. The block came at a time when no critical protests were happening. And now Tor users know that they can use pluggable transports or other connections that use bridges. Bridges are the hidden Internet pathways that are not easily detected or blocked. Tor now has 3,000 new users who are on bridges as a result.
