Putting together the pieces

I teach Internet and Media Law at Dalhousie Law School. Last night we had a guest speaker, Lisa Taylor, a CBC journalist and law school grad. One of the topics discussed was publication bans and how they are inadvertently compromised when different media outlets choose to disclose limited -- but different -- information. This got me thinking about other ways of piecing together information.

A while ago, I blogged about an article in the Halifax paper related to stores leaving card numbers unobscured on receipts (PIPEDA and Canadian Privacy Law: Article: Who has your number?). I've noticed that more and more stores are omitting many of the digits on debit card and credit card receipts.

While emptying the loads of junk from my pockets at the end of the day, I glanced at the pile of papers I had accumulated in the previous twenty four hours. I was happy to see that all of the stores I had visited had blocked out digits of my card numbers, presumably to protect their customers. When I took a closer look, I noticed that they are completely inconsistent in how they do it. Some leave only the first four and last four digits. Some omit the last digits. So if you took my little pile of papers, you could completely recreate my debit card number. Hm... Perhaps we need a little consistency in how we protect identities. If I had emptied my pockets into the garbage, anybody trolling through my trash for personal information would be able to get the card numbers. And expiry dates for credit cards. Perhaps the debit terminal manufacturers and distributors could get together and figure this out.