CBORs

CBORs, or Concise Binary Object Representation, is a data interchange format designed for small code size and compact message encoding. It is binary and self-describing, enabling efficient transmission and parsing on constrained devices and networks such as embedded systems and Internet of Things environments. The design emphasizes simplicity, extensibility, and predictable performance. CBOR supports a broad range of data types and can be encoded deterministically in its canonical form for cryptographic purposes and data comparisons.

CBOR encodes data using a small initial byte that combines a major type (0 to 7) with additional information that indicates the length or value. Major type 0 encodes unsigned integers; 1 encodes negative integers; 2 encodes byte strings; 3 encodes text strings (UTF-8); 4 encodes arrays; 5 encodes maps; 6 encodes semantic tags; and 7 encodes floating-point numbers and simple values. Indefinite-length items and streaming support are available. Tags provide semantic meaning for data, such as dates or specialized encodings, while simple values cover booleans, null, and undefined.

CBOR was standardized by the IETF and has become widely used in both IoT and broader data interchange. The base format is complemented by a canonical form that ensures a unique encoding for a given data item, which matters for digital signatures and hash-based comparisons. Real-world usage includes COSE for signing and encryption, WebAuthn-related data, and various protocols and APIs that require compact binary representations.