Converting security protocols from XML to JSON

I have "amused" myself with some initial conversions of KeyGen2 from XML to JSON.
The following shows one of the ten KeyGen2 message objects:
  
    {
        "@context": "http://xmlns.webpki.org/keygen2/201309018",
        "@qualifier": "KeyCreationRequest",
        "ServerSessionID": "S-140f2b70a3e4eefe1627b141e20",
        "ClientSessionID": "C-140f2b70ba0812f22188454b453",
        "SubmitURL": "http://issuer.example.com/keygen",
        "PUKPolicy": 
            [{
                 "ID": "PUK.1",
                 "Format": "numeric",
                 "RetryLimit": 3,
                 "Value": "mjRuOhjhtfg6d6d51Oqw",
                 "MAC": "xPr65fxq5hwvUX94Btpp5tey+yHH9iBrMLO7wQ2k5/0=",
                 "PINPolicy": 
                     [{
                          "ID": "PIN.1",
                          "Grouping": "shared",
                          "Format": "numeric",
                          "MinLength": 4,
                          "MaxLength": 8,
                          "RetryLimit": 3,
                          "PatternRestrictions": ["three-in-a-row","sequence"],
                          "MAC": "Hlzek4waNiqnWwrK83cvHE6MyoQh7N5frLEH4I3DpZ0=",
                          "KeyEntry": 
                              [{
                                   "ID": "Key.1",
                                   "KeyAlgorithm": "http://xmlns.webpki.org/sks/algorithm#ec.p256",
                                   "AppUsage": "authentication",
                                   "MAC": "idpbhr/L/4BnaLaxz5VJHC4/XPoyp3kR/s7Dcb7ywTM="
                               },
                               {
                                   "ID": "Key.2",
                                   "KeyAlgorithm": "http://xmlns.webpki.org/sks/algorithm#rsa2048",
                                   "AppUsage": "encryption",
                                   "MAC": "6KCho59vdV3hyXlKaQl3HQFPO32GzfXFbkJh4jsbQKA="
                               }]
                      }]
             }]
    }

This should be interpreted as a request for the client to create an EC key and an RSA key where both keys are protected by a single (shared) user-defined (within the specified policy limits) PIN. The PIN is in turn governed by an issuer-defined, protocol-wise secret PUK.

Since multiple instances of properties is considered as a bad JSON practice, arrays have been used instead.
For those who are versed in XML Schemas, @context is essentially the same as targetNameSpace while @qualifier represents an "emulation" of the top-level element in an XML instance document.

The original version in XML looks considerably cooler but machines probably don't care :-)

Cheers,
Anders