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Your comment is ridiculous. The number has structure, you don't get random IP addresses if you're a company. You get a block, likewise card issuers get a blo

Your comment is ridiculous. The number has structure, you don't get random IP addresses if you're a company. You get a block, likewise card issuers get a block (BIN - Bank Identifier Number) then add in the checksum, that definitely means you can't just assign random number. Imagine you have a random number. Visa get's the number and a charge for $20. Who owns it? They now have to search through all possible issued card number to find the card issuer. However with the BIN, they can do a pattern matching and send the info to the card issuer to determine if the card is valid. Think of the implementation details, those before you are not idiots as much as you may think they didn't think things through.

HenryBemis 6y ago
My thoughts of this made the parallelism with IP addresses. Japan's issue can be solved by "buying some numbers" from much smaller countries. The solution to reuse a number is bat shit crazy. Perhaps they can use expired cards (and not cancelled). In the long run the sensible solution (just like IP addresses) is to move from a "IPv4" system to a "IPv6" that will largely multiply the available numbers per country/bank/entity and will solve the problems, for the next many decades.
rswail 6y ago
What the OP said was that even with a 6 digit BIN and 1 digit check, you have 9 digits available per BIN. For example, Mastercards start in the range 51 to 55. That leaves 4 digits of the 6 digit BIN to allocate to MC issuers. So that's a total of 50K issuers of MC world wide, then each of those issuers can have 1 billion cards. So each issuer of a MC in Japan can issue a card to each member of the population and only use an eighth of their allocated range. The problem isn't the individual card account ID, from the article, it sounds like Japan has been allocating too many BINs.
- hrktb 6y ago
  > an eight of their allocated range Assuming your calculations are correct, this means an issuer can only emit 8 cards in average to the total population. Cards have an expiration, people lose them, break them, they change and come back to banks. For the main issuers it’s not ridiculous to have to issue 20 or 30 cards per account to a user in their lifetime. Then people have multiple accounts (e.g. my mortgage was on a separate join account). There’s just enough normal circumstances to run out of numbers, not even considering freak cases.
  - deleted 6y ago
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donor20 6y ago
I hope you are trolling. You understand that every possible prefix / range has a billion numbers minimum? That japans population is only 125 million? And actually - you can near randomly assign numbers if you wanted, looking up card issuer is not difficult. Can basically issue card numbers in blocks of 100 if you wanted to reduce lookup tables a bit. This is already happening and available actually. Visa and other (apple) offer tokenization services to randomize your card number. Every phone number uses this type of system to enable number portability as well (you can take your phone number from t-mobile to sprint). With 16 digits (1,234,567,890,123,456) you have 999 trillion numbers you can assign. As my original comment pointed out, the idea that we are running out of credit card numbers is absolutely ridiculous.

HenryBemis 6y ago

My thoughts of this made the parallelism with IP addresses. Japan's issue can be solved by "buying some numbers" from much smaller countries. The solution to reuse a number is bat shit crazy. Perhaps they can use expired cards (and not cancelled). In the long run the sensible solution (just like IP addresses) is to move from a "IPv4" system to a "IPv6" that will largely multiply the available numbers per country/bank/entity and will solve the problems, for the next many decades.

rswail 6y ago

What the OP said was that even with a 6 digit BIN and 1 digit check, you have 9 digits available per BIN. For example, Mastercards start in the range 51 to 55. That leaves 4 digits of the 6 digit BIN to allocate to MC issuers. So that's a total of 50K issuers of MC world wide, then each of those issuers can have 1 billion cards. So each issuer of a MC in Japan can issue a card to each member of the population and only use an eighth of their allocated range. The problem isn't the individual card account ID, from the article, it sounds like Japan has been allocating too many BINs.

hrktb 6y ago
> an eight of their allocated range Assuming your calculations are correct, this means an issuer can only emit 8 cards in average to the total population. Cards have an expiration, people lose them, break them, they change and come back to banks. For the main issuers it’s not ridiculous to have to issue 20 or 30 cards per account to a user in their lifetime. Then people have multiple accounts (e.g. my mortgage was on a separate join account). There’s just enough normal circumstances to run out of numbers, not even considering freak cases.
- deleted 6y ago
  [deleted]

donor20 6y ago

I hope you are trolling. You understand that every possible prefix / range has a billion numbers minimum? That japans population is only 125 million? And actually - you can near randomly assign numbers if you wanted, looking up card issuer is not difficult. Can basically issue card numbers in blocks of 100 if you wanted to reduce lookup tables a bit. This is already happening and available actually. Visa and other (apple) offer tokenization services to randomize your card number. Every phone number uses this type of system to enable number portability as well (you can take your phone number from t-mobile to sprint). With 16 digits (1,234,567,890,123,456) you have 999 trillion numbers you can assign. As my original comment pointed out, the idea that we are running out of credit card numbers is absolutely ridiculous.