Origami is a framework for PDF documents manipulation written in pure Ruby. It can be used to analyze or create malicious PDF documents. A GTK graphical interface is also available for manually browsing through the inner objects of a PDF document. New features include AES256 encryption/decryption of documents and G3 unidimensional encoding/decoding of CCITTFax streams. Can be used in many ways, even if you are new to the Ruby language. Can now be installed as a gem.
Source: https://thehackernews.com/2011/05/origami-10-released-pdf-manipulation.html