We face the same problem in protecting children against violent sexual exploitation. End-to-end and user-only-access encryption frequently prevent us from discovering and searching for victims, since the vital tips we receive from providers only arrive when those providers themselves are able to detect and report child exploitation being facilitated on their platforms and services. They cannot do that when their platforms are end-to-end encrypted. For example, while Facebook Messenger and Apple iMessage each boasts over one billion users, in 2020, the National Center for Missing and Exploited Children (NCMEC) received over 20 million tips from Facebook* compared to 265 tips from Apple, according to NCMEC data and publicly available information. Apple’s use of end-to-end encryption, which blinds it to child sexual abuse material being transmitted through its services, likely plays a role in the disparities in reporting between the two companies. We do not know how many children are being harmed across the country as a result of this under-reporting by Apple and other end-to-end providers.
*Facebook is planning to move its Facebook Messenger platform to end-to-end encryption as a default in the near future. This will result in the loss of even these tips.
https://www.fbi.gov/news/testimony/oversight-of-the-federal-bureau-of-investigation-061021