This repository contains resources associated with the CBOR::Core project.

Design Rationale

The purpose of CBOR::Core is providing a specification that can be supported by quite different platforms, while maintaining a high level of interoperability, including with respect to API. CBOR::Core has also been described as "a better JSON" 😊

Interoperability is achieved by:

• Compatibility with the CBOR base specification: RFC 8949
• Deterministic encoding, while optionally offering decoding support for "legacy" CBOR
• Strict type-checking at the API level as well as by the decoding process

Current Draft

The most recent draft can be found at: https://datatracker.ietf.org/doc/draft-rundgren-cbor-core/

Examples

The following simple examples are supposed to give an idea of how CBOR::Core is to be used. Although the examples build on a specific JavaScript solution, other implementations are supposed to be quite similar with respect to usage.

Encoding

const TEMPERATURE_KEY = CBOR.Int(1);
const GREETINGS_KEY = CBOR.Int(2);

let cbor = CBOR.Map()
               .set(TEMPERATURE_KEY, CBOR.Float(45.7))
               .set(GREETINGS_KEY, CBOR.String("Hi there!")).encode();

console.log(CBOR.toHex(cbor));
------------------------------
a201fb4046d9999999999a0269486920746865726521

Note: there are no requirements "chaining" objects like above.

Decoding

let map = CBOR.decode(cbor);  // cbor: from the encoding example
console.log(map.toString());  // Diagnostic notation
----------------------------------------------------
{
  1: 45.7,
  2: "Hi there!"
}

console.log('Value=' + map.get(TEMPERATURE_KEY).getFloat64());
--------------------------------------------------------------
Value=45.7

Using Diagnostic Notation

To simplify logging, documentation, and debugging, a conforming CBOR::Core implementation should also include support for the text-based CBOR-format known as "Diagnostic Notation".

However, diagnostic notation can also be used as input for creating CBOR based test data and configuration files from text:

let cbor = CBOR.fromDiagnostic(`{
# Comments are also permitted
  1: 45.7,
  2: "Hi there!"
}`).encode();

console.log(CBOR.toHex(cbor));
------------------------------
a201fb4046d9999999999a0269486920746865726521

On-line Testing

On https://cyberphone.github.io/cbor-core/playground/ you will find a simple Web application, permitting testing a conformant encoder, decoder, and diagnostic notation implementation.

Deterministic Encoding

For maintaining cross-platform interoperability, CBOR::Core mandates a fixed (aka "deterministic") encoding of CBOR objects.

To shield developers from having to know the inner workings of deterministic encoding, conforming CBOR::Core implementations perform all necessary transformations automagically. This for example means that if the set() operations in the Encoding Example were swapped, the generated CBOR would remain the same.

Known CBOR::Core Implementations

Language	URL
JDK 21+	https://github.com/cyberphone/openkeystore
Android/Java	https://github.com/cyberphone/android-cbor
JavaScript	https://github.com/cyberphone/CBOR.js#main
Python 3	https://github.com/cyberphone/CBOR.py#main

Updated: 2026-03-02