[kaffe] SHA1PRNG synchronization w/ reseed

jrandom auto97841 at hushmail.com
Tue Jan 20 16:30:02 PST 2004

Hi Tim,

> So, I'm not quite sure if it is supposed to be thread-safe... Can you
> point me to something? Anyways, I ended up just making setSeed/nextByte
> synchronized, hopefully that works for you.

Sounds great.  After looking over what I sent, the volatile doesn't seem
strictly necessary since all dangerous uses of those variables are in
the synchronized methods.

I couldn't find anything specifically requiring thread safety in the
SecureRandom docs, but the Random [1] docs do specify that their impl
is synchronized (plus running the same app I'm using under sun JVMs has
never shown the ArrayIndexOutOfBounds (or other runtime exception)).

Digging into the SPI specs didn't seem to include any mention of thread
safety (or lack thereof) either, so it seems that either the SHA1PRNG
could be threadsafe /or/ the SecureRandom.next(int) could synchronize
on the engine - both would be fine by me.  Not making either of them
threadsafe is of course an option, but if kaffe goes that route, it might
be best to toss a warning in the docs :)

> Also, I added some new stuff so that it initially pulls from
> "/dev/urandom" if it is available. So, if you experience anything
> strange, holler.

kickass!  thanks


[1] http://java.sun.com/j2se/1.4.1/docs/api/java/util/Random.html#next(int)

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