From 16d8a4dc293689f1bc09c859bd3278bdd5e46fdb Mon Sep 17 00:00:00 2001
From: Manu Sporny Transformations
Implementers are advised to consider these sorts of attacks when implementing
defensive security strategies.
-The VCWG is seeking feedback on normative language that cryptographic suite -implementers need to follow to ensure that they do not utilize data -transformation mechanisms that can map to the same output. That is, given -different inputs for canonicalization scheme #1 and canonicalization scheme #2, -they must not produce the same output value. As an analogy, this is the same -requirement for cryptographic hashing mechanisms and is why those schemes are -designed to be collision resistant. Cryptographic canonicalization mechanisms -have the same requirement. At present, this isn't a problem because the three -expected canonicalization schemes — the Universal RDF Dataset -Canonicalization Algorithm 2015 [[?RDF-CANON]], JSON Canonicalization -Scheme [[?RFC8785]], and a theoretical future base-encoding canonicalization -— have entirely different outputs. -
--The VCWG is seeking feedback on whether to explain why modern canonicalization -schemes are simpler than the far more complex XML Canonicalization schemes of -the early 2000s. Some readers seem to be under the impression that all -canonicalization is difficult and has to be avoided at all costs (including costs -to application developers). The WG would like to understand if it would be helpful -to include a section explaining why some simpler data syntaxes (such as JSON) are -easier to canonicalize than more complex data syntaxes (such as XML). -