The mendelson OFTP2 is a JAVA-based open source OFTP2 solution. It contains a logging- and configuration GUI (SWING) and supports encryption, digital signatures, message compression, TLS, certificate exchange, message routing, mail notification
AS2Secure is a PHP Lib to allow you to send and receive AS2 message from partners. Based on OpenSSL, documents are SIGNED and CRYPTED to build SMIME messages ready to be sent over HTTP connection.
Accord Odette is a Java framework for developing your own Odette OFTP2 client/server, respecting your needs of integration and functionalities. It comes with base client and server classes for TCP/IP and to bridge connections through X.25 and ISDN.