Sanitizable Signatures in XML Signature - Performance, Mixing Properties, and Revisiting the Property of Transparency

We present the performance measures of our Java Cryptography Architecture (JCA) implementation that integrates sanitizable signature schemes into the XML Signature Specification. Our implementation shows mostly negligible performance impacts when using the Ateniese scheme with four different chameleon hashes and the Miyazaki scheme in XML Signatures. Thus, sanitizable signatures can be added to the XML Security Toolbox. Applying the new tools we show how to combine different hash algorithms over different document parts adding and removing certain properties of the sanitizable signature scheme; this mixing comes very natural in XML Signatures. Finally, we motivate that existing definitions for the property of Transparency are counterintuitive in these combinations. Our conclusion is that the document-level Transparency property is independent of the sub-document properties Weak and Strong Transparency.