I think this topic came up a week or 2 ago, and I made an almost identical comment as you, which was why the content of my reply was fresh in my memory. Anyway,

I think this topic came up a week or 2 ago, and I made an almost identical comment as you, which was why the content of my reply was fresh in my memory. Anyway, in the recent convo, a kind hn poster provided this explanation of CVV https://randomoracle.wordpress.com/2012/08/25/cvv1-cvv2-cvv3-demystifying-credit-card-data-12/ https://randomoracle.wordpress.com/2012/08/25/cvv1-cvv2-cvv3... I totally see why it just seems like "moar numbers" though, and I find them unnecessarily annoying. I wish they could reduce the complexity (maybe letters, colors or shapes, something more human-compatible), but there's just too much legacy code with too little benefit.