The company is also considering banning the use of Messenger accounts not linked to regular Facebook profiles
Facebook will outline on Wednesday an expanded test of encryption on its Messenger platform, moving ahead with a controversial plan for enhanced security that regulators and government officials warn will aid criminals.
Executives told Reuters they will also detail safety measures, including stepped-up advisories for recipients of unwanted content.
The moves, which will be more fully described by company executives at a Lisbon tech conference, follow complaints by top law enforcement officials in the United States, United Kingdom and Australia that Facebook's intention to encrypt messaging on all its platforms would put child sex predators and pornographers beyond detection.
Facebook messaging privacy chief Jay Sullivan and other executives said the company, supported by civil rights groups and many technology experts, will continue to work toward the changeover, while more carefully scrutinizing the data that it does collect.
Sullivan plans to call attention to a little-publicized option for end-to-end encryption that already exists on Messenger, hoping that increased usage will give the company more data to craft additional safety measures before it makes private chats the default setting.
"This is a good test bed for us," Sullivan said. "It's part of the overarching direction."
Around the same time as the talk on Wednesday, the company will post more on its pages for users about how Secret Conversations function. The feature has been available since 2016 but is not easily discoverable by users and takes extra clicks to activate.
The company is also considering banning the use of Messenger accounts not linked to regular Facebook profiles. The vast majority of Messenger accounts are associated with Facebook profiles, but a greater proportion of stand-alone accounts are used for crime and unwelcome communications, executives said.
Requiring a link to Facebook would reduce the privacy protections of those Messenger users but give the company more information it could use to warn or block troublesome accounts or report suspected crimes to police.
The enhanced safety measures the company plans include sending reminders to users to report unwanted contacts and inviting recipients of unwanted content to send plain-text versions of the chats to Facebook to ban senders or potentially report them to police.
Facebook might also send more prompts to users reached by people with no shared friends or who have had many messages or friend requests rejected.
Facebook had previously said it wanted to ease user reporting of misconduct as it gradually moves toward more encryption, but it has given few details.