Re: (psuedo) random serial for PK or at least UNIQUE NOT NULL?

2010/5/5 Vincenzo Romano <vincenzo(dot)romano(at)notorand(dot)it>:
> 2010/5/4 Alvaro Herrera <alvherre(at)commandprompt(dot)com>:
>> Vincenzo Romano wrote:
>>> Hi all.
>>>
>>> I'm willing to change an BIGINT ID column (actually a SERIAL8) with a
>>> BIGINT whose valules are (pseudo)random.
>>> The main objective is to avoid guessability.
>>> I whish I could also use it as the PK (as it's now) but that's not
>>> really important now.
>>> Any hint?
>>
>> http://wiki.postgresql.org/wiki/Pseudo_encrypt
>
> That's a nice starting point.
> I should apply that function twice for each 32-bit chunk of a
> 64-bit BIGINT and then merge the results into a single BIGINT ...
> Boring but doable!

Hum, not sure. If I understand correctly, you won't be able to get the
original int64 from the generated one.
Better rewrite the function for 2^64 isn't it ?

>
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> Vincenzo Romano
> NotOrAnd Information Technologies
> NON QVIETIS MARIBVS NAVTA PERITVS
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--
Cédric Villemain