Digital signature (IMAGE) Ruhr-University Bochum Caption IT experts at RUB have found several security issues with digital signatures for PDF documents over the past years. Credit RUB, Kramer Usage Restrictions The image may only be used for reporting about Ruhr-Universität Bochum in the context of the press release "Two new attacks break PDF certification", published in May 2021. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.