important · Document trust
One signed PDF can present different visible content in Apple PDFKit and independent renderers.
Affects
Apple PDFKit, the PDF renderer used by Preview and applications on iPhone, iPad, and Mac.
Researchers placed an ordinary JPEG beneath a JPEG 2000 image in a JPX container. Apple PDFKit exposed the lower image, while independent renderers displayed the JPX layer.
Detail and 2 sources
That gives a sender one authenticated artifact whose visible meaning depends on the reviewer’s software.
While this divergence remains, high-consequence PDF reviews should compare a trusted rasterization or use the same controlled renderer on every side.