SSH to JWK (for node.js)

A minimal library to parse an SSH public key (id_rsa.pub) and convert it into a public JWK.

Works for RSA and ECDSA public keys.

Features

< 100 lines of code | <1kb gzipped | 1.8kb minified | 3.1kb with comments

• [x] SSH Public Keys (RFC 4253)
  • fingerprint
• [x] OpenSSH Private Keys
• [x] RSA
  • 2048, 3072, 4096
• [x] EC Public Keys
  • P-256 (prime256v1, secp256r1)
  • P-384 (secp384r1)
• [x] Browser Version
  • Bluecrypt SSH to JWK

Note: Lines of code have increased by about 2x since adding private key support.

Need JWK to SSH? SSH to PEM?

Try one of these:

• jwk-to-ssh.js (RSA + EC)
• Eckles.js (more EC utils)
• Rasha.js (more RSA utils)

Need SSH Private Keys?

Many SSH private keys are just normal PEM files, so you can use Eckles or Rasha, as mentioned above.

As for the OpenSSH-specific Private Keys, both EC and RSA are fully supported.

CLI

You can install ssh-to-jwk and use it from command line:

npm install -g ssh-to-jwk

ssh-to-jwk ~/.ssh/id_rsa.pub

ssh-to-jwk ~/.ssh/id_rsa

Usage

You can also use it from JavaScript:

SSH to JWK

var fs = require('fs');
var sshtojwk = require('ssh-to-jwk');
var ssh;

ssh = sshtojwk.parse({ pub: fs.readFileSync("./id_rsa.pub") });
console.info(ssh.jwk);

// For OpenSSH PEMs only, use Rasha for standard RSA or Eckles for standard EC
ssh = sshtojwk.parse({ pem: fs.readFileSync("./id_rsa") });
console.info(ssh.jwk);

SSH Fingerprint

var fs = require('fs');
var sshtojwk = require('ssh-to-jwk');
var pub = fs.readFileSync("./id_rsa.pub");

sshtojwk.fingerprint({ pub: pub }).then(function (fingerprint) {
  console.info(fingerprint);
  // SHA256:yCB62vBVsOwqksgYwy/WDbaMF2PhPijAwcrlzmrxfko
});

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