[whatwg] Cryptographically strong random numbers

Adam Barth w3c at adambarth.com
Fri Feb 11 13:36:47 PST 2011

On Fri, Feb 11, 2011 at 1:13 PM, Glenn Maynard <glenn at zewt.org> wrote:
> On Fri, Feb 11, 2011 at 3:40 PM, Adam Barth <w3c at adambarth.com> wrote:
>> In some cases, it's not possible to determine whether we'll be able to
>> get OS randomness until runtime.  For example, on Linux, if we don't
>> have permission to read /dev/urandom.
> You can have an exception, eg. INTERNAL_ERR or RUNTIME_ERR, for cases where
> the PRNG is normally expected to work but failed in a rare way at runtime.
> That's always possible in theory (eg. a read() from /dev/urandom returns an
> error), but is separate from feature testing since it can't be predicted,
> and it should be exceptionally rare.
>> Not all JavaScript engines have the ability to selectively disable DOM
>> APIs at runtime.
> If that's a concern, then all of the specs with the text I mentioned will
> have trouble.  I think either the convention of removing APIs at runtime
> should be expected and depended on by the specs (and used as consistently as
> is reasonable), or not used at all and those specs should be changed.

Regardless, the ability does not exist in JavaScriptCore.  If you'd
like to contribute a patch that makes it possible, I'm sure it would
be warmly received.


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