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A comment on Japan facing credit card number shortage. Parent comment

Re:Japan facing credit card number shortage by r00fus on Tuesday August 25, 2020 @06:16PM (#24276864)
Wouldn't the Luhn algorithm checksum [1] limit the available digits? It is specifically there so a one-off error doesn't result in a charge going to a valid other account.

[1] https://en.wikipedia.org/wiki/Luhn_algorithm

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Re:Japan facing credit card number shortage by contravariant on Tuesday August 25, 2020 @07:08PM (#24277320)
Most checksum algorithms that I know of for credit card numbers only decrease the number of available digits by 1.

Or equivalently it increases the length by the length of the checksum (usually 1 for credit cards) and doesn't otherwise affect the available numbers.

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Re:Japan facing credit card number shortage by bausano_michael on Tuesday August 25, 2020 @09:18PM (#24278072)
Great video on checksum was done by Ben Eater:

https://youtu.be/ppU41c15Xho

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Re:Japan facing credit card number shortage by senkora on Tuesday August 25, 2020 @06:34PM (#24277048)
I believe that’s what they mean by “check digit”.
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