What happened 

Apple announced it would introduce NeuralHash, a system designed to detect Child Sexual Abuse Material (CSAM) by scanning photos on a user's iPhone before they were uploaded to iCloud. 

Unlike competitors who scan data on their own servers, Apple proposed client-side scanning, which effectively placed an AI-powered monitoring tool directly on the user's hardware. While intended to protect children, privacy advocates, security researchers, and human rights groups argued it created a de facto "backdoor" into personal devices. 

The system sparked an immediate and intense reaction from the security and civil liberties community. Researchers demonstrated that the algorithm was vulnerable to "collisions," where non-harmful images could be engineered to trigger a false positive.

The EFF called it "a backdoor to increased surveillance and censorship around the world," while WhatsApp described it as "a surveillance system that could very easily be used to scan private content for anything they or a government decides it wants to control." 

Why it happened 

Like its competitors, Apple was under increasing pressure from law enforcement and child safety advocates to curb illegal content. 

However, the company's failure to account for the "slippery slope" of building surveillance architecture into consumer hardware was seen to have undermined the fundamental security of the device itself.