What does a SIN look like? Options

[kjones]

I know it doesn't really matter, but I've been wondering. I put together a dossier on a fictional character in my campaign so that I would have a cool feelie to give to my players. I was trying to figure out what kind of information would be on this, like occupation, DOB, criminal history. I realized that this dossier would probably have their SIN on it - but in order to do that, I would have to make some decision about what it actually is.

I settled on a 10-digit alphanumeric string of the form XXX-XX-XXXX (like an SSN), which leaves 36^10 = on the order of 1 quadrillion possible SINs, which seems like plenty. But I've been wondering, are there any official rulings on what a SIN looks like? I made the assumption that it serves as nothing more than a lookup into a database, but should it actually encode some information about a person in some meaningful way? (For example, the first two letters are their initials, the next six are their DOB... something like that.)