[concurrency-interest] ThreadLocalRandom clinit troubles (original) (raw)

Bernd ecki at zusammenkunft.net
Mon Jul 14 20:54:46 UTC 2014

SecureRandom is unfortunatelly pretty complex. It is interpreting the seed url in some way (the configuration you mentioned behave very special since Java 6) , it is mixing seed and continues data and it reorders the implementations used.

JEP 123 intended to clear things, but getInstanceStrong() (which nobody uses?!) did not improve things IMHO.

Bernd

PS: I think the webrev changed since then, but the mail from Brad describes the problem well: http://mail.openjdk.java.net/pipermail/security-dev/2013-January/006288.html Am 14.07.2014 21:05 schrieb "Oleksandr Otenko" <oleksandr.otenko at oracle.com

: Can someone summarize what happened?

SecureRandom used to get entropy from /dev/random, which is configurable through a policy file to /dev/urandom. Has this changed? Alex On 12/07/2014 00:33, Martin Buchholz wrote: Thanks to Peter for digging into the secure seed generator classes and coming up with a patch. Openjdk security folks, please review. I confess to getting lost whenever I try to orient myself in the twisty maze of seed generator implementation files. Anyways, it seems important to have prngs like ThreadLocalRandom be able to get a few bits of seed entropy without loading hundreds of classes and without occupying any file descriptors permanently. Perhaps at Google we will go back to writing some simple non-portable startup code to read /dev/urandom until openjdk security team comes up with a more principled solution (but one that doesn't drag in too much machinery).

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