Java client `computeX` is not `mod(N)`

[simon]

The JavaScript client code does:

this.x = this.fromHex(hash).mod(this.N());

Which is consistent with the original demo at http://srp.stanford.edu/demo/demo.html. The Java verifier generator got this correct but the Java HexHashedXRoutine dropped the final mod(N). This means that programs attempting to login from the Java code could potentially have a problem.

[simon]

The class TestJavaClient main method will run 10,000 mutual authentications which check the java session can login. This didn't show up the bug suggesting that the lack of the mod(N) wasn't actually breaking anything before it was corrected.