Re: [ANNC][RFC] crypto hashes for PostgreSQL 7.0, 7.1

On Sat, Oct 21, 2000 at 11:27:54PM +1000, Horst Herb wrote:
> > > >   http://www.l-t.ee/marko/pgsql/pgcrypto-0.1.tar.gz    (11k)
> 
> First of all, thankd for tis contribution. I had impemented a
> similar thing for my own purposes. A problem I still have is using
> the digest for "checksumming" rows in my tables - which is a 'MUST'
> for medico-legal reasons in my case. I use the follwing trigger and
> function (just a proof of concept implementation)
> 

[ pltcl trigger ]

> As you can see, the trigfunc_crc is fairly generic and will work
> with any table containing the attribute "crc".
> 
> Have you found a way of - making the trigger generic as well (I hate
> to rebuild all triggers for 300+ tables whenever I modify
> trigfunc_crc)

You do a trigfunc_crc_real which is called from trigfunc_crc?  I guess
you could then drop/create as you please?  Sorry, I do not speak Tcl
so I cant show how to do it exactly.  It will be a bit slower though.

> - any better performing way to implement trigfunc_crc ?

Hmm, probably you should at some point drop to C level.  It will
be a pain, so if the need is not too bad then you should avoid it.


Btw, the concept of checksumming rows is kinda new to me.
I needed this to store passwords on a table, so sorry if I
cant be more help.  But I am a litte bit curious, why is it
needed?  Simple checksumming (crc32/md5) does not help malicious
changing of data, only hardware failures, but today's hardware
has itself checksumming builtin...  It probably would be a
more point if you do some pgp/gpg style signing so you would
get some authenticy too, but this is hard to implement right.



-- 
marko