• Number of security experts have pulled out of conference • RSA accused of accepting $10m to create backdoor for NSA

Privacy rights groups are calling on comedian Stephen Colbert to cancel his guest speaker appearance at a conference organised by RSA, the security firm accused of accepting millions from the National Security Agency to weaken encryption software.

The host of Comedy Central’s Colbert Report is due to be the closing speaker at RSA’s annual conference in San Francisco in February. A number of security experts scheduled to speak at the conference have already dropped out following reports that RSA was paid $10m by the NSA to distribute a flawed encryption that allowed the security agency to bypass security protections on personal computers and other products.

The Guardian reported last September that the NSA was using a battery of methods to undermine encryption, the codes used to keep users’ data private online. Last month Reuters revealed that RSA was paid $10m by the NSA to incorporate a weakened algorithm into an encryption product called BSafe that would allow the spy agency easier access to protected information.

RSA has been one of the most respected names in online security. It is now part of EMC, one of the world’s largest data storage and cloud computing companies. The payment for the adoption of a flawed system by a company with a long history of championing online privacy caused widespread anger in the tech community.

The company has vehemently denied that it knowingly undermined its own encryption. “Recent press coverage has asserted that RSA entered into a ‘secret contract’ with the NSA to incorporate a known flawed random number generator into its BSafe encryption libraries. We categorically deny this allegation,” it said in a statement last month.

Digital rights group Fight For The Future has now set up an online petition asking Colbert to withdraw from the conference. “Last month, we learned that RSA accepted $10m from the NSA to stick a backdoor in one of their encryption products, and intentionally weaken the safety of the entire internet.

“We know you, Stephen, and we know you love a good backdoor as much as we do – but this is no laughing matter. By colluding with the NSA and covering it up, RSA has endangered all of us,” says the petition.

Earlier this week Google software engineer, Adam Langley, Mozilla’s global chief of privacy Alex Fowler and six other security and privacy experts announced they would cancel their talks at this year’s conference. “I've become convinced that a public stance serves more than self-aggrandisement, so: I've pulled out of the Cryptographers Panel at RSA 2014,” Langley said via Twitter.

Jeffrey Carr, a respected cybersecurity analyst, has also withdrawn from the conference and called for a boycott. “It's not enough to just talk about how bad this is. RSA's parent EMC, like every other corporation, has a board of directors that is answerable to its shareholders for maximizing revenue. If RSA's customers begin canceling their contracts and/or refuse to buy RSA products, the company's earnings will drop and that's the type of message that forces boards to make changes,” he wrote on his blog.

Holmes Wilson, co-founder of Fight For The Future, said: “Colbert isn’t a technologist but he understands this issue very well. His appearance at this conference will let participants laugh about something that is a very serious issue. I’d like to hear his speech too but this is not the venue.”

RSA and Colbert were not immediately available for comment.