I recently wanted to know which hash functions were available to Java in a given machine, so I cooked up a little command line tool for that. Maybe this could be useful to others so I posted it here.
Java hash functions are implemented as a MessageDigest object, which you can’t instance directly but rather get an instance through the MessageDigest.getInstance() static method. It takes as it’s only argument a string with the name of the algorithm – but I couldn’t find an easy way to enumerate all available algorithms.
After a little googling I found this code example at Example Depot to do it programatically. Since results may vary from one installation of Java to the next, a command line tool would have been more useful to me, but I don’t know of any. (If you do, let me know!)
Anyway, I wrapped the code in a very simple Main function and compiled it using Eclipse. I called this little tool “ListServices” because I didn’t feel like thinking of a catchy name.
By default this tool lists all available cryptographic providers, but you can specify just the ones you need (in the example below, we type MessageDigest to get just the hashing algorithms):
$ java -jar ListServices.jar KeyFactory: 1.2.840.1135188.8.131.52 OID.1.2.840.113549.1.1 1.2.840.113549.1.1 OID.1.2.840.1135184.108.40.206 220.127.116.11.2.12 DSA DiffieHellman RSA DH 1.2.840.10040.4.1 TransformService: INCLUSIVE_WITH_COMMENTS ENVELOPED (... output omitted for brevity ...) $ java -jar ListProviders.jar MessageDigest MessageDigest: SHA-256 SHA-512 SHA SHA-384 SHA1 MD5 SHA-1 MD2 $
Update: Added source code to Github.