Cross-platform Mobile OTP Agent

Hi, I need a mobile OTP agent that will run on all major mobile platforms. I expect Java is the easiest language for this goal, but I am open to any ideas that will work. The agent needs to follow the HOTP specification and work across iphone, android, blackberry and other java-enabled phones. I am open to (and encourage) use of existing opensource projects to reduce development time. Here are some ideas upon which the solution could be based: [login to view URL] [login to view URL] The first one seems like the best starting point. Let me know what questions need to be answered in order to deliver this solution.