Re: Random not so random - Mailing list pgsql-general

From Tom Lane
Subject Re: Random not so random
Date
Msg-id 14618.1096987020@sss.pgh.pa.us
Whole thread Raw
In response to Re: Random not so random  (Harald Fuchs <hf0722x@protecting.net>)
Responses Re: Random not so random  (Marco Colombo <pgsql@esiway.net>)
List pgsql-general
Harald Fuchs <hf0722x@protecting.net> writes:
>> Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>>> It might improve matters to make the code do something like
>>>> srandom((unsigned int) (now.tv_sec ^ now.tv_usec));

> I think we don't need the randomness provided by /dev/[u]random.  How
> about XORing in getpid?

That sounds like a fine compromise --- it'll ensure a reasonable-size
set of possible seeds, it's at least marginally less predictable than
now.tv_sec, and it's perfectly portable.  No one in their right mind
expects random(3) to be cryptographically secure anyway, so doing more
doesn't seem warranted.

The various proposals to create a more-secure, less-portable variant
of random() don't seem appropriate to me for beta.  But I'd not object
to someone whipping up a contrib module for 8.1 or beyond.

            regards, tom lane

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