How Google scans your Gmail for child porn

See the original posting on The Verge

John Henry Skillern was arrested last Thursday for the possession of child pornography. The 41-year-old restaurant worker was allegedly sending indecent images of children to a friend, but while it was Houston police that obtained a search warrant for Skillern’s tablet and computer and placed him in custody, it was Google that tipped them off to his illegal activities. Skillern was using Gmail to send images of child sexual abuse, each of which had been given a unique digital fingerprint. When those images were sent via Google’s email service, they were identified by the company’s automated systems, allowing it to pass Skillern’s details on to the police via the National Center for Missing and Exploited Children (NCMEC).

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