New York (CNN Business) US Attorney General William Barr and senior government officials from the UK and Australia are formally asking Facebook to give up on its plan to encrypt user messages across its platforms.

Facebook FB In an open letter toCEO Mark Zuckerberg made public Thursday, the officials wrote that while "law abiding citizens have a legitimate expectation that their privacy will be protected," effective encryption can hinder "our law enforcement agencies' ability to stop criminals and abusers in their tracks."

The letter was signed by Barr, acting US Secretary of Homeland Security Kevin McAleenan, UK Home Secretary Home Priti Patel, and Australian Minister for Home Affairs Peter Dutton.

The encryption debate, which pits tech companies that want to ensure user communications are private and secure against law enforcement's desire to access such messages, is decades old.

Some messaging services, such as Facebook's WhatsApp, utilize end-to-end encryption by default, meaning that only the individual devices an account is on — and not even the company that hosts the message — will have the keys to decrypt a conversation.

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