[104attendees] Side-meeting: Canonical JSON, Signed REST

[Anders Rundgren <[e-mail]>]

Wednesday 14-15 in Paris.

My presentations at IETF-104 couldn't go into details, so here some additional facts and motivations.

The lack of canonicalized JSON have had quite practical implications in IETF security protocols like in this one:

https://tools.ietf.org/html/draft-ietf-teep-opentrustprotocol-02

  "The top element "<name>[Signed][Request|Response]" cannot be fully
    trusted to match the content because it doesn't participate in the
    signature generation.  However, a recipient can always match it with
    the value associated with the property "payload".  It purely serves
    to provide a quick reference for reading and method invocation"

That is, the TEEP folks were forced adding a redundant (and IMO pretty ugly) JSON layer in order to tag objects since the JWS signature scheme dresses the payload in Base64Url.  This scheme also introduces an additional validation step.

This is sort of the opposite to my own work in this space, where canonicalization is also applied to the JWS container itself (aka clear text signatures).  Here an example from "Saturn":

  {
      "requestHash": {
          "alg": "S256",
          "val": "cA-QNdJHcynjuM44ty-zXgXwx100AZVRFLmYx1So0Xc"
      },
      "domainName": "demomerchant.com",
      "paymentMethod": "https://bankdirect.net",
      "accountId": "8645-7800239403",
      "timeStamp": "2019-03-23T10:33:02+01:00",
      "signature": {
          "alg": "ES256",
          "jwk": {
              "kty": "EC",
              "crv": "P-256",
              "x": "rQ4WXMB6_wQKHSiY_mbJ4QkGpfWLssF7hvIiiFpDEx8",
              "y": "Fh2rl0LGTtvaomOuhuRNo9Drz9o0--WXV2ITvdVQFRY"
          },
          "val": "j2LL9pr2RyrPxvFlj8IzMhno5vvgGIgf2xi23dA5u_XwjYlIvT9qwIVKaCKYwjb26J5mMUL5zV02lqQGjZRClw"
      }
}

Recent proposal addressing Signed/JSON/REST since this apparently still is missing:
https://tools.ietf.org/html/draft-rundgren-signed-http-requests-00
https://datatracker.ietf.org/meeting/104/materials/slides-104-hotrfc-3-signed-http-requests-shreq-00

Bring your rotten tomatoes if you want :-)

Cheers,
Anders