JEFF is an explanation facility framework written in Java. Explanation facilities date from the era of expert systems (ES), where they were used in order to provide an explanation about the inference process. The explanation they provided was supposed to clarify how the ES reached its conclusions or why it asked some question during fact acquisition. Nowadays, traditional ES development environments ("shells") have been replaced by rule engines (RE) and business rule management systems (BRMS), which seem to lack explanation facility functionality. JEFF was created in order to remedy this.
SignPDF is a simple command line application to sign a PDF document. It can sign a PDF document with a valid certificate, encrypt/protect a PDF document, and timestamp a PDF document (optional feature). A JKS keystore with a cert signed by your desired CA is mandatory for use. The tsa_url of a timestamp server can be used to timestamp your documents. The signed PDF file is signed and protected with allowed restrictions to printing, content copying, and content copying for accessibility. By default, SignPDF creates a configuration file at ~/.signpdf, which can be edited for further use.