This specification describes a standard signature suite created in 2016 for the Koblitz Elliptic Curve, also known as secp256k1, used by Bitcoin and Ethereum.

This is an experimental specification and is undergoing regular revisions. It is not fit for production deployment.

This specification describes a standard signature suite created in 2016 for the Linked Data Signatures [[LD-SIGNATURES]] specification. It uses the RDF Dataset Normalization Algorithm [[RDF-DATASET-NORMALIZATION]] to transform the input document into its canonical form. It uses SHA-256 [[RFC6234]] as the message digest algorithm and SECp256k1 [[SEC2]] as the signature algorithm.

The following terms are used to describe concepts involved in the generation and verification of the Koblitz Elliptic Curve Signature 2016 signature suite.

- signature suite
- A specified set of cryptographic primitives typically consisting of a canonicalization algorithm, a message digest algorithm, and a signature algorithm that are bundled together by cryptographers for developers for the purposes of safety and convenience.
- canonicalization algorithm
- An algorithm that takes an input document that has more than one possible representation and always transforms it into a canonical form. This process is sometimes also called normalization.
- message digest algorithm
- An algorithm that takes an input message and produces a cryptographic output message that is often many orders of magnitude smaller than the input message. These algorithms are often 1) very fast, 2) non-reversible, 3) cause the output to change significantly when even one bit of the input message changes, and 4) make it infeasible to find two different inputs for the same output.
- signature algorithm
- An algorithm that takes an input message and produces an output value where the receiver of the message can mathematically verify that the message has not been modified in transit and came from someone possessing a particular secret.

The Koblitz Signature 2016 signature suite MUST be used in conjunction with the signing and verification algorithms in the Linked Data Signatures [[LD-SIGNATURES]] specification. The suite consists of the following algorithms:

Parameter | Value | Specification |
---|---|---|

canonicalizationAlgorithm | https://w3id.org/security#URDNA2015 | [[RDF-DATASET-NORMALIZATION]] |

digestAlgorithm | http://w3id.org/digests#sha256 | [[RFC6234]] |

signatureAlgorithm | http://w3id.org/security#koblitz | [[SEC2]] |

No modifications to the Linked Data Signature algorithms are provided other than the algorithms specified in the previous signature suite section.

The following section describes security considerations that developers implementing this specification should be aware of in order to create secure software.

TODO: We need to add a complete list of security
considerations.

A simple example of a Koblitz 2016 Signature:

{ "@context": ["http://schema.org/", "https://w3id.org/security/v1"], "description": "Hello world!", "signature": { "type": "EcdsaKoblitzSignature2016", "created": "2016-10-23T05:50:16Z", "creator": "ecdsa-koblitz-pubkey:020d79074ef137d4f338c2e6bef2a49c618109eccf1cd01ccc3286634789baef4b", "domain": "example.com", "signatureValue": "H1jslvQ08/hAiqUSNiGoAYqU8sRCrwkgcNO/9xKxqZJTAX5v5SbAcBv69wrAQovBHR9ddfwvW1Skogbi1odGt7o=" } }