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Old 03-07-2013, 02:12 PM   #9
Gigem
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Join Date: Feb 2012
Location: Lakeway, TX
Posts: 335
Re: Having trouble decoding my VIN.

Quote:
Originally Posted by Keith Seymore View Post
Yes - a random number generated to verify it's not a bogus (ie "made up") VIN.

K
A check digit is not random at all. There is an algorithm used to derive the check digit from the other numbers and characters in the string being verified. Here is a simple example...

Maybe you want to add a check digit to your phone number. Maybe your algorithm is to add up the digits of your phone number, then use the "ones" component of that as your check digit.

713-555-1212. add up those digits, sum is 32. So your check digit is 2. If you put that digit at the end, you would code this as 71355512122. If someone saw 71355512129, they would know this is invalid...

If people don't know the algorithm, they won't know what to use for the check digit. Helps combat fraud.
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