Signing message with certificate: JCE, IAIK or similar in IBM SDK 5.0
So, I'm in a very difficult problem.
I've an enterprise certificate (in .p12 format) altogether with its public key ("password" string). Also I've a text message which I've to sign in PKCS7 format. I've been reading a lot and I've realized that there's no STANDARD implementation to do what I want to do. There is the JCE/JCA API and the Certification API, but they are just API's, no implementation. Here are the facts:
-I've to run the application in the IBM JDK 5.0 (AS400 system).
-My application actually works in the SUN JDK 6.0 using the IAIK security provider, but not using JCE, its a very ugly code which I dont know really what it does, but it works. When I put it on the IBM JDK 5.0 it fails (java nullpointer blah blah).
-IAIK Documentation says that it works on JDK 5.0. Yeah, it works, but in SUN implementation, not in IBM's.
Today I don't know what the heck to do, really. What do you think it's the best solution?
-Trying to make the IAIK code work in IBM SDK 5.0 by test-and-error method.
-Trying to sign the message using JCE and the IBM JCE provider (this is what I'm actually trying to do). It would be very nice if somebody provides something to read about (I've read lot of IBM/SUN documentation and I couldnt find anything useful for now.
-Trying to put the SUN JDK 6.0 in the AS400. This would be the easy solution but my bosses said that this is impossible and very dangerous, and additionally this wouldn't work.
-Also I've another code which uses the BouncyCastle provider but this doesn't work. Would this be better to learn how to use? I prefer using standards, though.
I've 4 security providers: IBM, SUN, IAIK and BouncyCastle (just IAIK works, and I need IBM), and
I've 4 SDK's: IBM 5.0, IBM 6.0, SUN 5.0 and SUN 6.0 (just SUN/IBM 6.0 works, and I need IBM 5.0).
I would like any documentation useful to read. I would provide any information which could be important to answer my question.