About Johns Hopkins


Return to News Releases

Johns Hopkins Expert Can Discuss Apple’s Plan to Monitor iPhones for Child Sexual Abuse

August 5, 2021
Kait Howard
Cell: 443-301-7993
kehoward@jhu.edu jhunews@jhu.edu

Apple has announced plans to scan iPhones and other Apple devices for images of child sexual abuse and report them to the National Center for Missing and Exploited Children. A Johns Hopkins University expert is available to discuss how the technology works, as well as potential privacy concerns.

Matthew D. Green is an associate professor of computer science and a nationally recognized expert on applied cryptography and cryptographic engineering. A member of the Johns Hopkins Information Security Institute, he has written widely about Apple’s privacy methods and led a research team that worked with Apple to fix a security bug in the iMessage app.

“This is a really bad idea,” Green wrote on Twitter. “These tools will allow Apple to scan your iPhone for photos that match a specific perceptual hash and report them to Apple servers if too many appear.”

“The ability to add scanning systems like this to end-to-end encryption messaging systems has been a major ask by law enforcement the world over,” wrote Green. “This sort of tool can be a boon for finding child pornography in people’s phones. But imagine what it could do in the hands of an authoritarian government.”

To request an interview with Green, please contact Kait Howard, kehoward@jhu.edu.


Johns Hopkins University news releases are available online, as is information for reporters. To arrange an interview with a Johns Hopkins expert, contact a media representative listed above. Find more Johns Hopkins experts on the Experts Hub, and more Johns Hopkins stories on the Hub.

Office of Communications
Johns Hopkins University
3910 Keswick Road, Suite N2600
Baltimore, Maryland 21211
Phone: 443-997-9009 | Fax: 443 997-1006