generic-sd-cwt.cddl

sd-cwt = #6.18([
   protected: bstr .cbor sd-protected,
   unprotected,
   payload: bstr .cbor sd-payload,
   signature: bstr
])

sd-protected = {
   &(alg: 1): int, 
   &(typ: 16): text,
   * key => any   
}

unprotected = {
   ? &(sd_claims: TBD1): [ +salted ],
   ? &(sd_kbt: TBD2): bstr,    ;.cbor sd-cwt-kbt,
   * key => any   
}

sd-payload = {
    ; standard claims
    ? &(iss: 1): tstr, ; "https://issuer.example"
    ? &(sub: 2): tstr, ; "https://device.example"
      &(aud: 3): tstr, ; "https://verifier.example"
    ? &(exp: 4): int,  ; 1883000000
    ? &(nbf: 5): int,  ; 1683000000
      &(iat: 6): int,  ; 1683000000
    ? &(cnf: 8): { * key => any }, ; key confirmation
    ? &(cnonce: 39): bstr
    ;
    ; sd-cwt new claims
    ? &(sd_hash: TBD3): bstr, ; 
    ? &(sd_alg: TBD4): int,            ; -16 for sha-256
    ? &(redacted_keys: TBD5): [ * bstr ]
   * key => any   
}

;redacted_element = { "...": bstr }
salted = salted-claim / salted-element
salted-claim = bstr .cbor [
  bstr ;.size 16,     ; 128-bit salt
  (int / text),      ; claim name
  any                ; claim value
]
salted-element = bstr .cbor [
  bstr ;.size 16,     ; 128-bit salt
  any                ; claim value
]

key = int / text
TBD1 = 1111
TBD2 = 1112
TBD3 = 1113
TBD4 = 1114
TBD5 = 1115