CreateAttachmentData takes a DID Document, and key and key id referenced in that document The attachment is a b64 encoded version of the did document in a detached JWS.

VerifyAttachmentData takes in a DIDComm `Data` object along with a keyID to validate the data It is assumed that the data is a DID Document, which contains the key referenced by the parameter.

Attachment is a structure used to attach Base64 encoded data to DIDComm messages.

Data contains the base64 encoded data and an optional JWS.

JWS Structure is JWS (RFC 7515) format and used for signing data.