Oct. 4 (UPI) -- U.S. Attorney General William Barr told Facebook CEO Mark Zuckerberg that if he is going to encrypt the messages of his services' users, he must allow law enforcement access to their content to protect the public.
Barr said Facebook needs to find a balance between protecting user information and allowing investigators lawful access to their messages during the course of investigations into terrorism and child pornography cases, among others.
"Not doing so hinders our law enforcement agencies' ability to stop criminals and abusers in their tracks," Barr said in a letter Friday addressed to Zuckerberg from Barr, acting Homeland Security Secretary Kevin McAleenan and Peter Dutton and Priti Patel, the law enforcement chiefs of Australia and Britain.
In the letter, the law enforcement heads said they support encryption and respect Facebook's promise to protecting user data, but added, "we must ensure that technology companies protect their users and others affected by their users' online activities."
In January, Facebook announced plans to integrate the messaging services of Facebook, WhatsApp and Instagram into a new end-to-end encrypted service, which protects messages from being viewed by anyone other than those in the conversation.
While applauding Facebook for its work to crack down on illegal content, the letter criticized Facebook's proposal as exacerbating the risk to public safety through combining inaccessible messaging services with public profiles that provide "unique routes for prospective offenders to identify and groom our children."
"Companies should not deliberately design their systems to preclude any form of access to content, even for preventing or investigating the most serious crimes," it said. "This puts our citizens and societies at risk by severely eroding a company's ability to detect and respond to illegal content and activity."
The security chiefs are calling on Zuckerberg to allow authorities lawful access to content, to engage in consultations with governments over Facebook's plan and delay implementing the plan until it has been fully tested.
Facebook said it supports law enforcement's fight against terrorism and child exploitation, but condemned the attempt to force access to its users' private conversations.
"End-to-end encryption already protects the messages of over a billion people every day," Facebook spokesman Andy Stone said. "We strongly oppose government attempts to build back doors because they would undermine the privacy and security of people everywhere."
Later Thursday, Barr and Patel, Britain's secretary of state for the Home Department, signed the world's first CLOUD Act Agreement that allows American and British law enforcement agencies to demand electronic data from tech companies in either country for investigations into terrorism, child sexual abuse and cybercrime. The agreement considerably reduces the two-year time period to access information by removing legal barriers, the Justice Department said in a statement.
"This agreement will make the citizens of both countries safer, while at the same time assuring robust protections for privacy and civil liberties," Barr said.