AS2Secure is a PHP library that allows you to send and receive AS2 (Applicability Statement 2) messages from partners. The project is split into two parts: a client to send one or more documents to a partner and a server to receive one or more documents from a partner. Its main features are asyncronous and syncronous MDN, partner setup, digital signatures, message encryption, secure transport (using OpenSSL), support for SSL client authentication, and multiple attachments (AS2 1.2).
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.