Apple has unveiled plans to scan U.S. iPhones for images of child sexual abuse, drawing applause from child protection groups but raising concern among some security researchers that the system could be misused, including by governments looking to surveil their citizens.
The tool designed to detect known images of child sexual abuse, called “neuralMatch,” will scan images before they are uploaded to iCloud. If it finds a match, a human will review the image. If child pornography is confirmed, the user’s account will be disabled and the National Center for Missing and Exploited Children will be notified.
The system will not flag images not already in the center’s child pornography database. Parents snapping innocent photos of a child in the bath presumably need not worry. But researchers say the matching tool — which doesn’t “see” such images, just mathematical “fingerprints” that represent them — could be put to more nefarious purposes.
Matthew Green, a top cryptography researcher at Johns Hopkins University, warned that the system could be used to frame innocent people by sending them seemingly innocuous images designed to trigger matches for child pornography. That could fool Apple’s algorithm and alert law enforcement. “Researchers have been able to do this pretty easily,” he said of the ability to trick such systems.
Other abuses could include government surveillance of dissidents or protesters. “What happens when the Chinese government says, ‘Here is a list of files that we want you to scan for,’ ” Green asked. “Does Apple say no? I hope they say no, but their technology won’t say no.”
Tech companies including Microsoft, Google, Facebook and others have for years been sharing digital fingerprints of known child sexual abuse images. Apple has used those to scan user files stored in its iCloud service, which is not as securely encrypted as its on-device data, for child pornography.
Apple has been under government pressure for years to allow for increased surveillance of encrypted data. Coming up with the new security measures required Apple to perform a delicate balancing act between cracking down on the exploitation of children while keeping its high-profile commitment to protecting the privacy of its users.
The computer scientist who more than a decade ago invented PhotoDNA, the technology used by law enforcement to identify child pornography online, acknowledged the potential for abuse of Apple’s system but said it was far outweighed by the imperative of battling child sexual abuse.
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