Internet users in Pakistan might have a harder time protecting their information — from authority interception and crooks alike — after a ban on virtual private networks (VPNs) takes effect.

The Pakistan Telecommunications Authority sent a legal notice to the country's ISPs, ordering them to turn in customers who use VPNs, The Guardian reports. According to the notice, anyone who wants to use a VPN needs to ask for special permission.

VPNs allow you to go undetected while using the Internet and sending messages. They are commonly used to access blocked sites or to create a secure network for a business's remote employees.

Pakistani authorities say the purpose of the ban, which was instated in 2010 but was not seriously enforced, is to inhibit terrorist communications. All Internet activity in Pakistan is routed through the state-run Pakistan Internet Exchange, creating an easy opportunity for the government to monitor messages that aren't protected by a VPN.

Paul Ducklin, Sophos's head of technology for Asia Pacific, argues in a blog post that the ban will also make it much easier for crooks to hijack valuable information. "An Internet in which encryption was banned altogether would be even more dangerous than what we have today," he writes.

Bans on encryption software aren't rare. India, China and Iran are just a few of the countries that require some state approval for encryption software.

It's not the first time Pakistan has drastically restricted its citizens' online actions. Last year, a court ordered authorities to temporarily ban Facebook due to a contest calling for caricatures of the Prophet Muhammad. Authorities also blocked YouTube due to sacrilegious content.