Path: utzoo!genat!perle!dave
From: dave@perle.UUCP (Dave LeReverend)
Newsgroups: can.general
Subject: Re: SIN Number
Summary: If there's a problem, it's not MINE!
Keywords: Problem?  What Problem?
Message-ID: <423@perle.UUCP>
Date: 22 Dec 88 17:41:04 GMT
References: <302@idacom.UUCP> <723@apss.apss.ab.ca> <1902@pembina.UUCP> <420@perle.UUCP> <4367@hcr.UUCP>
Reply-To: dave@perle.UUCP (Dave LeReverend)
Distribution: can
Organization: Perle Systems Limited  Scarborough, Ontario, Canada
Lines: 58

In article <4367@hcr.UUCP> paul@compiler.UUCP (Paul Jackson) writes:

[A summarized version of the (slightly) ambiguously-stated algorithm for
 calculating the ninth digit of a SIN has been deleted.]
 
>	This algorithm did NOT work for my SIN (my arithmetic is admittedly
>up to the usual standards in this society, but dc wouldn't lie to me, would
>it?)

"dc"?  Direct current?  District of Columbia?  Oh, yeah!  That's the crazy
RPN alleged calculator program.  I gave up on THAT during my first week on the
system.  Give me a solar-powered TI any day.

Well, before I posted the original article, I had only tried this algorithm
on my own SIN, and I got the proper result.  

So far, I've heard from two people on The Net who have tried this algorithm
on their own SIN, and both of them reported that it did NOT work.  This does
not mean that it did not work for anyone on The Net; perhaps it worked for
many people, and they just didn't bother posting a positive result.

Two of my co-workers were trusting enough to loan me their SINs (as if I don't
have enough of my own :-), and everything came out properly.

I did learn one thing from this process; if the result of step 6 is a multiple
of 10, then the last digit in the SIN should be a zero.

I believe that the algorithm which I posted is correct.  No-one has shown me
a valid SIN which cannot be verified in the manner I described.  Perhaps the
confused parties could e-mail me their SIN, and I could look into things 
further.  Believe me; I really don't care how much you invested in RSP's 
last year.

I also noticed something about Chris Shaw's method for altering SINs.  He 
suggests switching the following pairs of digits:

	Those at positions 4 and 6.
	Those at positions 3 and 5.
	Those at positions 5 and 7.

The algorithm which I posted indicated that ANY of the digits in odd-numbered
positions can be re-arranged in any way, and the check-sum will not change.
Things get complicated with the even-position digits, because the "times 2"  
step can cause carries.  It seems to me that the digits in positions 3 and 5,
as well as those in positions 5 and 7 CANNOT just be switched in an arbitrary
manner.

Enough of this; I've got a spec. to write.

David LeReverend

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"This summer, come on out to Saskatchewan and ... sit around."

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