![EBSI Logo](https://ec.europa.eu/digital-building-blocks/sites/images/logo/default-space-logo.svg)

# EBSI Key Encoder

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

## Table of Contents

1. [Installation](#installation)
2. [Getting Started](#getting-started)
3. [Encoding Private Keys](#encoding-private-keys)
4. [Encoding Public Keys](#encoding-public-keys)
5. [License](#license)

## Installation

```
npm install @cef-ebsi/key-encoder
```

## Getting Started

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

### SECP256k1 Key Encoders

```js
import { KeyEncoder } from "@cef-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

```js
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

```js
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

```js
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

```js
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

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

Example output:

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

### Encoding Public Keys to DER Format

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

Example output:

```
3056301006072a8648ce3d020106052b8104000a03420004147b79e9e1dd3324ceea115ff4037b6c877c73777131418bfb2b713effd0f502327b923861581bd5535eeae006765269f404f5f5c52214e9721b04aa7d040a75
```

## License

Copyright (C) 2025 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>.