Hi Chris,

Appreciate the feedback.

> On 05 May 2016, at 05:04, Chris Newman <[email protected]> wrote:
> 
> I am opposed to using CBOR. CBOR is not well deployed. Most codebases need 
> XML and JSON parsers but do not need CBOR parsers. So choosing CBOR 
> significantly increases the code complexity. My codebase has a JSON and XML 
> parser but no CBOR parser. I would strongly prefer to keep it that way, so 
> CBOR would introduce an unnecessary deployment barrier.

To be upfront: I'm not, and never have been, a particular fan of CBOR myself. 
But I think some kind of binary format would be useful.

> Binary formats have an extremely poor track record for security-sentive 
> applications. ASN.1 BER/DER has been an utter disaster for real-world 
> security in PKIX (there are probably hundreds of CVE reports due to ASN.1 
> parser bugs including many in TLS/SSL/PKIX stacks). We should not repeat this 
> design error in a security-sensitive context again.

There're very simple binary formats (CBOR is rather complex). We don't have to 
use ASN.1 nor BER nor DER. And I would never want to go that way.

> JSON parsers are widely used, simple and have been well analyzed for security 
> usage. They are a good choice for a security sensitive context (excluding the 
> naive Javascript implementation). Most deployed JSON parsers are 
> secure-by-default.

Do you have any references to the above statement? I'm not sure I'd sign that 
verbatim. I think a lot of JSON libraries that are out there are completely 
unaudited, especially for scripting languages.

> I think JSON is the best choice for this use case. I can personally live with 
> XML because I’ve built my own secure-by-default XML-subset parser (which is 
> about 3x the size/complexity of my JSON parser), but I think it’s an inferior 
> choice to JSON for security-sensitive applications.

While I cared little about the discussion in STS about switching from XML to 
JSON, I do prefer the latter as well.

> If data size is a concern, then deflate is the answer. Deflate is likely to 
> compress JSON far better than CBOR. While deflate is subject to the security 
> problems that binary formats have (including several releases with known 
> security vulnerabilities), I believe it’s been around long enough that 
> reasonably trustworthy implementations are now available (including current 
> zlib releases). I’m not convinced data size is a concern.

Well. Depending on the channel we use for feedback, DEFLATE might be a poor 
option:

- http://breachattack.com/
- 
https://www.blackhat.com/docs/asia-16/materials/asia-16-Karakostas-Practical-New-Developments-In-The-BREACH-Attack.pdf

Aaron

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