Example = {
   title: tstr,                                 # summary of test
   ? description: tstr,                         # longer description of test
   ? fail : bool,                               # Is this a success or failure test
   input: Inputs,                               # Inputs to create the test
   ? intermediates : Intermediates,             # Intermediate values for debugging
   output: Outputs                              # Outputs of the test
}

Inputs = {
   plaintext: bstr / tstr,
   ? detached: bool,
   (enveloped: Enveloped) /                     # Create an enveloped Message
   (encrypt: Encrypt) /                         # Create an encrypt Message
   (mac: Mac) /                                 # Create a MAC message
   (mac0: Mac0) /                               # Craete a MAC0 message
   (sign: Sign),
   ? failures : FailureSet,                     # Description of failure changes applied
   ? rng_description : tstr,                    # What is what in the RNG stream
   ? rng_stream: [+ tstr]                       # Random number generator stream - encoded as hex
}

Sign = {
  signers: [+ Signers]
}

headers = (
   ? protected: { +header_items },          # Protected headers to be sent
   ? unprotected: { +header_items },        # Unprotected headers to be sent
   ? unsent: { +header_items }              # Headers not to be sent
}

header_items = (
   "alg" : tstr,                                # Algorithm parameter
   "kid" : tstr,                                # key identifier - cast to bstr
   "kid_hex" : tstr,                            # key identifier - encoded as hex
   "epk" : key,                                 # ephemeral key
   "spk" : key,                                 # static key
   "spk_kid" : tstr,                            # static key identifier - cast to bstr
   "spk_kid_hex" : tstr,                        # static key identifier - encoded as hex
   "apu_id" : tstr,                             # PartyU identifier - cast to bstr
   "apu_nonce_hex" : tstr,                      # PartyU nonce - encoded as hex
   "apv_id" : tstr,                             # PartyV identifier - cast to bstr
   "pub_other" : tstr,                          # Public other Info - cast to bstr
   "salt" : tstr,                               # Salt value - cast to bstr
)

Signers = {
  alg: tstr,
  key: Key,
  headers
}

Mac = {
  alg: tstr,
  headers,
  recipients: [+ Recipients]
}

Mac0 = {
  alg: tstr,
  headers
}

Encrypt = {
    alg: tstr,
    headers
}

Enveloped = {
    alg: tstr,
    headers,
    recipients: [+ Recipients]
}

Recipient = {
   alg: tstr,
   ? fail: bool,                                # does this recipient fail
   headers,                                     # Headers for the recipient
   key: Key,                                    # Recipient Key
   ? sender_key: Key,                           # Sender key
   failures: Failures                           # Set of failures to apply to recipient
}

Key = {
  (tstr/int) => *
}

Failures = {
}

Outputs = {
   ? cbor: bstr,                                # CBOR encoding in HEX
   ? cbor_diag: tstr,                           # CBOR Diagnositc encoding
   ? content : bstr                             # deatched content encoded in HEX
}

Intermediates = {
   ? "ToMax_hex": tstr,                         # Value to be MAC-ed encoded in HEX
   ? "CEK_hex": tstr,                           # CEK used in MAC or encryption encoded in hex
   ? "AAD_hex": tstr,                           # AEAD Additional Data encoded in hex
   ? "recipients" : [ +{
       ? "Context_hex": tstr,                   # Context structure encoded in hex
       ? "Secret_hex" : tstr,                   # ECDH shared secret encoded in hex
   }]
   ]
}