[jose] JWK Generator

[Justin Richer <[e-mail]>]

A while ago, several folks complained that there was no toolchain for 
creating bare keys in the JWK/JPSK format. Indeed, my team's been using 
Java's keytool program and making self-signed dummy certs and pulling 
them out of there. That was a bit of a pain, to be honest.

So now I've just written a utility program to generate JWK formatted 
keys from whole cloth given a set of parameters. It's a Java app built 
using the NimbusDS JWT-JOSE library, and at the moment it supports both 
RSA and oct keytypes, with an option to extract the public-only portion 
of the RSA as well. This is all based on the current JPSK format, which 
we plan to track with the aforementioned Nimbus library.

You can get the code here:

   https://github.com/mitreid-connect/json-web-key-generator

It's open sourced under an Apache 2.0 license, so feel free to pull it 
down and use it to your heart's content. It's a Java Maven project, so 
you build it with:

   mvn package

This will create a couple of .jar files in the target/ directory, one of 
which is an executable fat jar, usble from the commandline:

    usage: java -jar json-web-key-generator.jar -t <keyType> -s <keySize> [-u

                 <keyUsage> -a <algorithm> -i <keyId> -p]

      -a <arg>   Algorithm.

      -i <arg>   Key ID (optional)

      -p         Display public key separately

      -s <arg>   Key Size in bits, must be an integer, generally divisible by 8

      -t <arg>   Key Type, one of: RSA, oct

      -u <arg>   Usage, one of: enc, sig. Defaults to sig


For instance, to generate a 1024-bit RSA key with the algorithm of 
RS256, no key id, and display the public key separately, you would run 
(after doing a mvn package):

   java -jar 
target/json-web-key-generator-0.1-SNAPSHOT-jar-with-dependencies.jar -a 
RS256 -t RSA -s 1024 -p

This prints out (for example, your keys should vary):

    Full key:

    {

       "alg": "RS256",

       "d": "IXhRb4mXMOLlX1nEcv--CRX5WjGZdUTHzI2qIg-iX5QXY-noSZqit-BeWO0CTwBtryCU4DgNIjV4cvYHpWqkr8ES-FoH7DHDgt41lH5_YDv-MeeCU3hRSPbACLuWEbWQfjgLPgIL1cmh1q-eFOEpXWUtKy7DCFymMves7ojPxY0",

       "e": "AQAB",

       "n": "kWkuetDiodUI-0jZ2KpmwOMJ7jsnO8qG8ChMs7ax3xXKIr5g5K0axWtXm1HwA5OJRE-OyVHfJkda6xVgTFaV1AhWP8Zp7KL_Oq-moKRe5-BtahHpFJe7HZ1P6hxXAdhaygXen1lR0NAMNi4K4H5pn1KDCeRpuxAhJZsQnq5dxp0",

       "kty": "RSA",

       "use": "sig"

    }

    Public key:

    {

       "alg": "RS256",

       "e": "AQAB",

       "n": "kWkuetDiodUI-0jZ2KpmwOMJ7jsnO8qG8ChMs7ax3xXKIr5g5K0axWtXm1HwA5OJRE-OyVHfJkda6xVgTFaV1AhWP8Zp7KL_Oq-moKRe5-BtahHpFJe7HZ1P6hxXAdhaygXen1lR0NAMNi4K4H5pn1KDCeRpuxAhJZsQnq5dxp0",

       "kty": "RSA",

       "use": "sig"

    }


To create a 256-bit symmetric key with algorithm HS256 and key id of 
"myKey", you'd do:

   java -jar 
target/json-web-key-generator-0.1-SNAPSHOT-jar-with-dependencies.jar -t 
oct -s 256

Which outputs something like:

    Full key:

    {

       "kty": "oct",

       "use": "sig",

       "k": "CsoV5LeX6S3RRlLr-hk0_VyIuTOWyovMPbU2UmbphME"

    }


It doesn't do EC keys yet because I don't know the Java Magic needed to 
make such a thing happen, but I'd be happy to have someone help out with 
that with a pull request.

Hopefully people find this utility useful. I've got a few features I'm 
planning to add (write output to files, Java GUI with dropdowns for 
options), but this is a minimally-useful set of functionality.

  -- Justin