The Technical Summary uses "visual derivative" without clarification, but their Threat Model PDF clarifies it further as thumbnails: >The decrypted vouchers al

The Technical Summary uses "visual derivative" without clarification, but their Threat Model PDF clarifies it further as thumbnails: >The decrypted vouchers allow Apple servers to access a visual derivative – such as a low-resolution version – of each matching image. https://www.apple.com/child-safety/pdf/Security_Threat_Model_Review_of_Apple_Child_Safety_Features.pdf https://www.apple.com/child-safety/pdf/Security_Threat_Model...