Activists plan to use an internet signalling system to help co-ordinate protests against the proposed US Cyber Intelligence Sharing and Protection Act (Cispa).
The proposed legislation is aimed at helping the US government contend with cyber attacks through allowing easier information-sharing between security agencies and private web firms.
Unlike the failed Stop Online Privacy Act (Sopa), technology companies such as Facebook, Intel and Microsoft are among 800 US-based companies that have reacted positively to the bill.
But US civil liberties groups have expressed concerns about the transparency of the bill. Some critics argue that a lack of clarity in the bill could lead to unjustified shutting-down of websites or massive eavesdropping on private communications.
Activists say that, if enacted in its current form, Cispa would erode privacy by exposing people's browsing habits and would be used to justify domestic surveillance.
Read more about Cispa
- Cispa cyber security legislation wins industry support
- US House of Representatives passes controversial cyber security bill Cispa
- Cyber Intelligence Sharing and Protection Act of 2011 (Cispa)
- Barack Obama signs cyber security executive order
- Facebook to back US cyber security snooping bill
- Cyber security legislation mired as executive order looms
Social news sites such as Reddit, Craigslist and Fark joined rights groups to set up the Internet Defense League (IDL), which monitors threats to online privacy.
Some IDL members have embedded code in the websites they control, so protest materials are shown automatically when the signal, known as the “cat-signal”, is activated.
The IDL – which is to create protest materials such as website banners – wants the signal to act as a call to action to co-ordinate protests, just as the "bat-signal" does for fictional superhero Batman.
The signal has been activated this week as Cispa is debated in the US Senate for the second time, with thousands of websites expected to display an interactive banner from the IDL, according to Mashable.
The banner allows users to send the following message to their members of Congress: "Cispa is back. This bill sacrifices privacy without improving security. We deserve both."
Opposition to Cispa, from US President Barack Obama's advisers because of insufficient safeguards, led to it being vetoed in November 2011 at its first Senate outing.