Checking Credit Cards (#122)
in [Ruby]
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From: Christoffer Lernö on 28 Apr 2007 08:43 On Apr 27, 2007, at 23:06 , James Edward Gray II wrote: > On Apr 27, 2007, at 3:10 PM, anansi wrote: > >> James Edward Gray II wrote: >>> On Apr 27, 2007, at 12:58 PM, Matthew Moss wrote: >>>> So is a card number like "4012 3456 7890" a valid Unknown, or an >>>> invalid Visa? >>> Visa Invalid >>> Always match the type first. >> >> Nope thats no Visa number but a unknown one. Visa Cards have a >> certain length (13 or 16) and if that length doesn't fit >> (Matthew's number here had just 12 digits)it's unknown :) >> otherwise the length would be obsolete don't you think? >> Both length and startingbytes have equal weight in the decision >> wether a card belongs to a known Company or not. > > You are right. I didn't read well. It's Unknown. > > James Edward Gray II Do we display Valid/Invalid for unknown cards? - And by the way: 4012 3456 7890 isn't valid is it? So should that not be "invalid Unknown" or "invalid Visa"? /C
From: anansi on 28 Apr 2007 09:03 Christoffer Lern� wrote: >> James Edward Gray II > > Do we display Valid/Invalid for unknown cards? > We desplay unknown for unkown cards :) and valid/invalid for valid or invalid cards, the first has nothing to do with the second. Check first if it's a known one which depends on both the length and the starting bytes. Then output if it's a known or unknown one. After that, check the known or unknown number for validation and output that result. > - And by the way: 4012 3456 7890 isn't valid is it? So should that not > be "invalid Unknown" or "invalid Visa"? > > /C That's a unknown and invalid one. To be a Visa one it would need to be 13 or 15 bytes long. -- greets ( ) ( /\ .-"""-. /\ //\\/ ,,, \//\\ |/\| ,;;;;;, |/\| //\\\;-"""-;///\\ // \/ . \/ \\ (| ,-_| \ | / |_-, |) //`__\.-.-./__`\\ // /.-(() ())-.\ \\ (\ |) '---' (| /) ` (| |) ` jgs \) (/ one must still have chaos in oneself to be able to give birth to a dancing star
From: anansi on 28 Apr 2007 09:05 anansi wrote: > That's a unknown and invalid one. To be a Visa one it would need to be > 13 or 15 bytes long. > 13 or 16 of course... -- greets ( ) ( /\ .-"""-. /\ //\\/ ,,, \//\\ |/\| ,;;;;;, |/\| //\\\;-"""-;///\\ // \/ . \/ \\ (| ,-_| \ | / |_-, |) //`__\.-.-./__`\\ // /.-(() ())-.\ \\ (\ |) '---' (| /) ` (| |) ` jgs \) (/ one must still have chaos in oneself to be able to give birth to a dancing star
From: James Edward Gray II on 28 Apr 2007 11:43 On Apr 28, 2007, at 7:43 AM, Christoffer Lernö wrote: > On Apr 27, 2007, at 23:06 , James Edward Gray II wrote: > >> On Apr 27, 2007, at 3:10 PM, anansi wrote: >> >>> James Edward Gray II wrote: >>>> On Apr 27, 2007, at 12:58 PM, Matthew Moss wrote: >>>>> So is a card number like "4012 3456 7890" a valid Unknown, or >>>>> an invalid Visa? >>>> Visa Invalid >>>> Always match the type first. >>> >>> Nope thats no Visa number but a unknown one. Visa Cards have a >>> certain length (13 or 16) and if that length doesn't fit >>> (Matthew's number here had just 12 digits)it's unknown :) >>> otherwise the length would be obsolete don't you think? >>> Both length and startingbytes have equal weight in the decision >>> wether a card belongs to a known Company or not. >> >> You are right. I didn't read well. It's Unknown. >> >> James Edward Gray II > > Do we display Valid/Invalid for unknown cards? > > - And by the way: 4012 3456 7890 isn't valid is it? So should that > not be "invalid Unknown" or "invalid Visa"? I would go ahead and display Valid/Invalid normally. That way people can use the program on cards we didn't cover, as long as they conform to the standard. James Edward Gray II
From: Jeremy Hinegardner on 28 Apr 2007 12:48
On Fri, Apr 27, 2007 at 08:59:49PM +0900, Ruby Quiz wrote: > The first check people often do is to validate that the card matches a known > pattern from one of the accepted card providers. Some of these patterns are: > > +============+=============+===============+ > | Card Type | Begins With | Number Length | > +============+=============+===============+ > | AMEX | 34 or 37 | 15 | > +------------+-------------+---------------+ > | Discover | 6011 | 16 | > +------------+-------------+---------------+ > | MasterCard | 51-55 | 16 | > +------------+-------------+---------------+ > | Visa | 4 | 13 or 16 | > +------------+-------------+---------------+ Wikipedia has a great chart showing all the prefixes of most known credit cards, along with lengths and overlap between cards (currently none). http://en.wikipedia.org/wiki/Credit_card_number enjoy, -jeremy -- ======================================================================== Jeremy Hinegardner jeremy(a)hinegardner.org |