cose.cddl

; start = COSE_Messages / COSE_Key / COSE_KeySet / Internal_Types

; This is defined to make the tool quieter:
Internal_Types = Sig_structure / Enc_structure / MAC_structure /
        COSE_KDF_Context

label = int / tstr
values = any

COSE_Messages = COSE_Untagged_Message / COSE_Tagged_Message
      
COSE_Untagged_Message = COSE_Sign / COSE_Sign1 /
    COSE_Encrypt / COSE_Encrypt0 /
    COSE_Mac / COSE_Mac0

COSE_Tagged_Message = COSE_Sign_Tagged / COSE_Sign1_Tagged /
    COSE_Encrypt_Tagged / COSE_Encrypt0_Tagged /
    COSE_Mac_Tagged / COSE_Mac0_Tagged

Headers = (
    protected : empty_or_serialized_map,
    unprotected : header_map
)

header_map = {
    Generic_Headers,
    * label => values
}

empty_or_serialized_map = bstr .cbor header_map / bstr .size 0


Generic_Headers = (
    ? 1 => int / tstr,  ; algorithm identifier
    ? 2 => [+label],    ; criticality
    ? 3 => tstr / int,  ; content type
    ? 4 => bstr,        ; key identifier
    ? 5 => bstr,        ; IV
    ? 6 => bstr,        ; Partial IV
    ? 7 => COSE_Signature / [+COSE_Signature] ; Counter signature
)

COSE_Sign_Tagged = #6.98(COSE_Sign)

COSE_Sign = [
    Headers,
    payload : bstr / nil,
    signatures : [+ COSE_Signature]
]

COSE_Signature =  [
    Headers,      
    signature : bstr
]

COSE_Sign1_Tagged = #6.18(COSE_Sign1)

COSE_Sign1 = [
    Headers,
    payload : bstr / nil,
    signature : bstr
]

Sig_structure = [
    context : "Signature" / "Signature1" / "CounterSignature",
    body_protected : empty_or_serialized_map,
    ? sign_protected : empty_or_serialized_map,
    external_aad : bstr,
    payload : bstr
]

COSE_Encrypt_Tagged = #6.96(COSE_Encrypt)

COSE_Encrypt = [
    Headers,
    ciphertext : bstr / nil,
    recipients : [+COSE_recipient]
]

COSE_recipient = [    
    Headers,
    ciphertext : bstr / nil,
    ? recipients : [+COSE_recipient]
]

COSE_Encrypt0_Tagged = #6.16(COSE_Encrypt0)

COSE_Encrypt0 = [
    Headers,
    ciphertext : bstr / nil,
]

Enc_structure = [
    context : "Encrypt" / "Encrypt0" / "Enc_Recipient" /
        "Mac_Recipient" / "Rec_Recipient",
    protected : empty_or_serialized_map,
    external_aad : bstr
]

COSE_Mac_Tagged = #6.97(COSE_Mac)

COSE_Mac = [
   Headers,
   payload : bstr / nil,
   tag : bstr,
   recipients :[+COSE_recipient]
]

COSE_Mac0_Tagged = #6.17(COSE_Mac0)

COSE_Mac0 = [
   Headers,
   payload : bstr / nil,
   tag : bstr,
]

MAC_structure = [
     context : "MAC" / "MAC0",
     protected : empty_or_serialized_map,
     external_aad : bstr,
     payload : bstr
]

COSE_Key = {
    1 => tstr / int,          ; kty
    ? 2 => bstr,              ; kid
    ? 3 => tstr / int,        ; alg
    ? 4 => [+ (tstr / int) ], ; key_ops
    ? 5 => bstr,              ; Base IV
    * label => values
}

COSE_KeySet = [+COSE_Key]

PartyInfo = (
    identity : bstr / nil,
    nonce : bstr / int / nil,
    other : bstr / nil,
)

COSE_KDF_Context = [
    AlgorithmID : int / tstr,
    PartyUInfo : [ PartyInfo ],
    PartyVInfo : [ PartyInfo ],
    SuppPubInfo : [
        keyDataLength : uint,
        protected : empty_or_serialized_map,
        ? other : bstr
    ],
    ? SuppPrivInfo : bstr
]