EBSI Key Encoder

This library is a fork of https://www.npmjs.com/package/key-encoder.

Table of Contents

1. Installation
2. Getting Started
3. Encoding Private Keys
4. Encoding Public Keys
5. License

Installation

npm install @europeum-ebsi/key-encoder

Getting Started

To get started, first define your key encoder and raw private/public keys.

SECP256k1 Key Encoders

import { KeyEncoder } from "@europeum-ebsi/key-encoder";
const keyEncoder = new KeyEncoder("secp256k1");

As shown above, there is built in support for SECP256k1 (the curve Bitcoin uses), but you can pass in your own curve parameters for any curve you'd like.

Key Encoders w/ Custom Curves

const encoderOptions = {
  curveParameters: [1, 3, 132, 0, 10],
  privatePEMOptions: { label: "EC PRIVATE KEY" },
  publicPEMOptions: { label: "PUBLIC KEY" },
  curve: "secp256k1",
};
const keyEncoder = new KeyEncoder(encoderOptions);

Declaring Raw Keys

const rawPrivateKey =
  "844055cca13efd78ce79a4c3a4c5aba5db0ebeb7ae9d56906c03d333c5668d5b";
const rawPublicKey =
  "04147b79e9e1dd3324ceea115ff4037b6c877c73777131418bfb2b713effd0f502327b923861581bd5535eeae006765269f404f5f5c52214e9721b04aa7d040a75";

Encoding Private Keys

Encode to and from raw, PEM (encode to 'pkcs8' and 'pkcs1'), and DER formats.

Encoding Private Keys as PEMs

const pemPrivateKey = keyEncoder.encodePrivate(
  rawPrivateKey,
  "raw",
  "pem",
  "pkcs8",
); //default is 'pkcs1'

Example output:

-----BEGIN PRIVATE KEY-----
MIGNAgEAMBAGByqGSM49AgEGBSuBBAAKBHYwdAIBAQQghEBVzKE+/XjOeaTDpMWr
pdsOvreunVaQbAPTM8VmjVugBwYFK4EEAAqhRANCAAQUe3np4d0zJM7qEV/0A3ts
h3xzd3ExQYv7K3E+/9D1AjJ7kjhhWBvVU17q4AZ2Umn0BPX1xSIU6XIbBKp9BAp1
-----END PRIVATE KEY-----

Encoding Private Keys to DER Format

const derPrivateKey = keyEncoder.encodePrivate(rawPrivateKey, "raw", "der");

Example output:

30740201010420844055cca13efd78ce79a4c3a4c5aba5db0ebeb7ae9d56906c03d333c5668d5ba00706052b8104000aa14403420004147b79e9e1dd3324ceea115ff4037b6c877c73777131418bfb2b713effd0f502327b923861581bd5535eeae006765269f404f5f5c52214e9721b04aa7d040a75

Encoding Public Keys

Encode to and from raw, PEM, and DER formats.

Encoding Public Keys as PEMs

const pemPublicKey = keyEncoder.encodePublic(rawPublicKey, "raw", "pem");

Example output:

-----BEGIN PUBLIC KEY-----
MFYwEAYHKoZIzj0CAQYFK4EEAAoDQgAEFHt56eHdMyTO6hFf9AN7bId8c3dxMUGL
+ytxPv/Q9QIye5I4YVgb1VNe6uAGdlJp9AT19cUiFOlyGwSqfQQKdQ==
-----END PUBLIC KEY-----

Encoding Public Keys to DER Format

const derPublicKey = keyEncoder.encodePublic(rawPublicKey, "raw", "der");

Example output:

3056301006072a8648ce3d020106052b8104000a03420004147b79e9e1dd3324ceea115ff4037b6c877c73777131418bfb2b713effd0f502327b923861581bd5535eeae006765269f404f5f5c52214e9721b04aa7d040a75

License

Copyright (C) 2026 European Union

This program is free software: you can redistribute it and/or modify it under the terms of the EUROPEAN UNION PUBLIC LICENCE v. 1.2 as published by the European Union.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the EUROPEAN UNION PUBLIC LICENCE v. 1.2 for further details.

You should have received a copy of the EUROPEAN UNION PUBLIC LICENCE v. 1.2. along with this program. If not, see https://joinup.ec.europa.eu/collection/eupl/eupl-text-eupl-12.