Tutorial Environment for Cryptographic Protocols (TECP) is a tutorial and visualization environment for public key cryptography. It is intended for students of cryptography courses and can be used to improve understanding of modular arithmetic-based public key algorithms, and for lecturers who want to add some life to boring blackboard-and-chalk presentations about the topic.
Treebeard is an XSLT IDE that allows you to load an XML file and an XSLT file (from the Web or from the local file system), edit either file, and then perform transformations. Some features include syntax highlighting, a pluggable XSLT transformer, a template browser, SAX transformations (so you can transform large files - 4MB tested), regular expression find, and displaying transformation results in HTML or plain text.
OpenXAdES enables people to work with legally-binding digital signatures (primarily giving and verifying them). Legislation often defines a set of requirements that legal digital signature technologies and infrastructures must be compliant with, and OpenXAdES aims at meeting many, if not all, such requirements from different legislations.