I am using apache fop on a linux server, using the command line to convert my xml to pdf using my xsl file which I wrote using an xml editor. Can anyone point me in the direction of where to start if I want to add a security certificate to my pdf so that anyone reading knows it is from a trusted source? Will I have to use a java program to transform and create the pdf rather that the fop command line in order to do this? Also, I'm interested in embedding a bardcode in the pdf too. If anyone has suggestions or links or how to do this using my current method or if I have to approach it a different way then I'd be glad to hear from you.
I doubt that FOP has any capabilities like that. I'm fairly certain iText can do it; iText also has some barcode-creation facilities specifically geared towards embedding barcodes in PDFs.
Note that here are two versions of iText: 2 (licensed under the LGPL) and 5 (licensed under the Affero GPL). The latter version generally requires you to obtain a license in any business setting. See http://www.coderanch.com/how-to/java/ItextExample for some more information on both versions.