Usage
Invoking the utility without arguments will print its usage message

usage java -jar json-web-key-generator.jar -t keyType [options]
 -a arg   Algorithm (optional)
 -c arg   Key Curve, required for EC key type. Must be one of P-256,
            P-384, P-521
 -i arg   Key ID (optional)
 -p         Display public key separately
 -s arg   Key Size in bits, required for RSA and OCT key types. Must be
            an integer divisible by 8
 -S         Wrap the generated key in a KeySet
 -t arg   Key Type, one of RSA, oct, EC
 -u arg   Usage, one of enc, sig (optional)
Example
To generate a 2048-bit RSA public  private key pair, with a specified key ID and use, and wrapped in a standard JWK set

java -jar json-web-key-generator.jar -t RSA -s 2048 -i 1 -u sig -S