Concise Binary Object Representation (CBOR) is data format designed for small code size and small message size. There is a need for the ability to have the basic security services defined for this data format. This document defines the CBOR Object Signing and Encryption (COSE) specification. This specification describes how to create and process signature, message authentication codes and encryption using CBOR for serialization. This specification additionally specifies how to represent cryptographic keys using CBOR.