CborLabel

CBOR supports keys of all sorts, not just Strings. In the COSE context, these keys are called labels and are limited to Strings and 64-bit negative integers and 64-bit unsigned integers. Conceptually, these work just as SerialNames, but to also support numbers in addition to Strings, this annotation can be used.

Set the preferCborLabelsOverNames configuration switch to prefer them over serial names in case both are present for a property.

Example usage:

@Serializable
data class DataClass(
    @CborLabel(1)
    @SerialName("alg")
    val alg: Int
)

serializing DataClass(alg = -7) with Cbor { preferCborLabelsOverNames = true } will output 0xbf0126ff, or in diagnostic notation:

BF    # map(*)
   01 # unsigned(1)
   26 # negative(6)
   FF # primitive(*)

instead of the traditional 0xbf63616c6726ff, or in diagnostic notation:

BF           # map(*)
   63        # text(3)
      616C67 # "alg"
   26        # negative(6)
   FF        # primitive(*)