# ecdsa-sig-formatter

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Translate between JOSE and ASN.1/DER encodings for ECDSA signatures

## Install

```sh
npm install ecdsa-sig-formatter --save
```

## Usage

```js
var format = require('ecdsa-sig-formatter');

var derSignature = '..'; // asn.1/DER encoded ecdsa signature

var joseSignature = format.derToJose(derSignature);

```

### API

***

#### `.derToJose(Buffer|String signature, String alg)` -> `String`

Convert the ASN.1/DER encoded signature to a JOSE-style concatenated signature. Returns a *base64 url* encoded `String`.

* If *signature* is a `String`, it should be *base64* encoded
* *alg* must be one of *ES256*, *ES384* or *ES512*

***

#### `.joseToDer(Buffer|String signature, String alg)` -> `Buffer`

Convert the JOSE-style concatenated signature to an ASN.1/DER encoded signature. Returns a `Buffer`

* If *signature* is a `String`, it should be *base64 url* encoded
* *alg* must be one of *ES256*, *ES384* or *ES512*

## Contributing

1. **Fork** the repository. Committing directly against this repository is highly discouraged.
2. Make your modifications in a branch, updating and writing new unit tests as necessary in the `spec` directory.
3. Ensure that all tests pass with `npm test`
4. `rebase` your changes against master. *Do not merge*.
5. Submit a pull request to this repository. Wait for tests to run and someone to chime in.

### Code Style

This repository is configured with [EditorConfig](http://editorconfig.org/) and [ESLint](http://eslint.org) rules.


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