dsig/README.md

Digital Signature with OpenPGP

DSIG
====

Digital Signature with OpenPGP in JavaScript

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<img src="https://nodei.co/npm/dsig.png?downloads=true&stars=true" alt=""/>

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<img src="https://david-dm.org/rse/dsig.png" alt=""/>

About
-----

DSIG (Digital Signature) is a JavaScript Application Programming
Interface (API) and Command-Line Interface (CLI) for generating an
[OpenPGP](https://www.ietf.org/rfc/rfc4880.txt) public/private key
pair, calculating the fingerprint of the public/private key, signing a
payload with the private key and verifying the payload afterwards with
the public key and the fingerprint. It is especially intended to sign
application license files and application distribution archive files.

The crux of DSIG is:

1. It is based on [OpenPGP.js](https://openpgpjs.org/), and as a
   consequence, it is a plain JavaScript solution which does not require
   an installed [GnuPG](https://gnupg.org/) and its native `gpg` command
   and works in both [Node.js](https://nodejs.org/) and the Browser.

2. The private key, public key, fingerprint and signature
   use a fully valid [OpenPGP](https://www.ietf.org/rfc/rfc4880.txt)
   format and hence they *could* even be used with GnuPG, although the
   DSIG signature is a clear-signed OpenPGP message carrying both the
   SHA-512 digest of the payload and optional meta information.

Installation
------------

```shell
$ npm install [-g] dsig
```

Example
-------

See the Example section of the [Unix manual page](src/dsig-cli.md#example)
for an example how to prepare public/private key pair and fingerprint,
and then sign and verify an application distribution archive or an
application runtime license. A corresponding standalone
[Bourne shell script](./test.sh) and [equivalent Web page](./test.html)
can be used for test-driving DSIG, too.

Usage
-----

- Command-Line Interface:<br/>
  See [Unix manual page](src/dsig-cli.md).

- Application Programming Interface (API):<br/>
  See [TypeScript API definition](src/dsig-api.d.ts).

License
-------

Copyright &copy; 2015-2022 [Dr. Ralf S. Engelschall](http://engelschall.com/)<br/>
Licensed under [LGPL 3.0](https://spdx.org/licenses/LGPL-3.0-only)