How to use crypto api keys with forge

[bfoerster]

Hi,
is there a way to use browsers crypto api key generation with forge?
I create a keypair using the crypto api and want to convert the resulting private key to PEM format, so i can use it in forge or export it.

var crypto = window.crypto.subtle;
crypto.generateKey({
        name: "RSA-OAEP",
        modulusLength: 2048,
        publicExponent: new Uint8Array([0x01, 0x00, 0x01]),
        hash: {
            name: "SHA-256"
        },
    },
    true, ["encrypt", "decrypt"]).then(function (keyPair) {
    //jwk, pkcs8
    crypto.exportKey("jwk", keyPair.privateKey).then(function (exportedPrivateKey) {
        // How to convert to PEM or forge format?
        console.log(keyPair.privateKey);
        console.log(exportedPrivateKey);
    });
});

The problem is that i cannot find a way to convert between the different formats or how to tell forge that it should use window.crypto.subtle.generateKey for key generation.

Hope somebody can help me :)

[stonehouse]

This would help me out a lot too!

[dlongley]

This is related to #255. You probably just want to export as 'pkcs8' and then convert to a forge buffer and use forge's asn1 API calls from there. Let me see if I can get it working real quick.

[dlongley]

This worked for me:

(function() {

var crypto = window.crypto.subtle;
crypto.generateKey({
  name: "RSA-OAEP",
  modulusLength: 2048,
  publicExponent: new Uint8Array([0x01, 0x00, 0x01]),
  hash: {
    name: "SHA-256"
  },
}, true, ["encrypt", "decrypt"]).then(function(keyPair) {
  crypto.exportKey("pkcs8", keyPair.privateKey).then(
    function(exportedPrivateKey) {
      // How to convert to PEM or forge format?
      console.log(keyPair.privateKey);
      console.log(exportedPrivateKey);

      // convert to forge buffer, then from DER, then export to PEM
      var buffer = new forge.util.ByteBuffer(exportedPrivateKey);
      var asn1 = forge.asn1.fromDer(buffer);
      var privateKey = forge.pki.privateKeyFromAsn1(asn1);
      var pem = forge.pki.privateKeyToPem(privateKey);
      console.log(pem);
    });
});

})();

Depending on what you want to do, you may be able to instead just base64-encode the exported PKCS8-formatted ArrayBuffer and then wrap it in a PEM header. But the above demonstrates how to get the key into something forge can use and export with its API.

[bfoerster]

Worked for me too!!!!!
You are the best! Thank you very much!

[stonehouse]

You are my hero!

[dlongley]

Haha! Great, glad it worked for you guys. :)