- From: Peter Patel-Schneider <pfpschneider@gmail.com>
- Date: Mon, 07 Jun 2021 19:07:39 -0400
- To: Eric Prud'hommeaux <eric@w3.org>
- Cc: semantic-web@w3.org
On Mon, 2021-06-07 at 22:49 +0200, Eric Prud'hommeaux wrote: > On Mon, Jun 07, 2021 at 03:37:44PM -0400, Peter Patel-Schneider > wrote: [..] > > Since then, you have claimed with full confidence that you have found > 10s of critical flaws with what I resolutely call "RDF Signatures". > None turned out to be critical flaws. I would say a few, not 10s. I pointed out what I think are flaws in the algorithms in https://w3c-ccg.github.io/ld-proofs/, particularly when using JSON-LD. [...] > A third related to changing the meaning of JSON-LD documents by > changing the @context. This isn't related to signatures, and if > anything, signatures give you a tool to prevent that because you've > signed a the resulting document and if someone changes the the > @context under you, you can't verify the signature. > > Those were, afaict, the only substantial critiques. Most were of the > form "if you change X, the hash changes and the signature breaks" to > which the reply is "by design". Remote contexts are indeed problematic for JSON-LD documents. They can cause failures in both directions. If the remote context is changed the deserialization of the document may change, invalidating signatures of documents that use the remote context. But I believe that attackers can also use remote contexts to change signed JSON-LD documents in a way that validation by recipients will succeed but when the recipient deserializes the document they end up with an RDF dataset that is not isomorphic to the dataset signed by the originator. I believe that this is the case even if the orignal signed JSON-LD document does not use remote contexts. > If you approached this with a bit more humility, it would be less > galling, but as it is, you keep making strident claims, fighting them > for a while, and when the couter-evidence is overwhelming, quietly > dropping them in favor of some new strident claim. It doesn't really > give the impression that you're arguing in good faith. I'm still waiting for an implementation of the algorithms that I can use to demonstrate my claimed attacks. Once I have this implementation I'll try out my attacks using it and report back my experiences. With the partial implementation I have been given I've noticed and reported that remote contexts in JSON-LD cannot be signed so I can't try the initial remote contexts attack I came up with. The Web GUI you put up at https://janeirodigital.github.io/rdf-sig-playground/index was useful but it doesn't take JSON-LD and appears to produce quite different output.
Received on Monday, 7 June 2021 23:08:53 UTC