Why 45992700 Is Not 459927: Longest-Prefix-First BIN Matching for Korean Cards
Here is a small quiz. A user in Seoul types a card number that starts with 4599 2700. Your card-type detector looks at it and says, confidently: Visa. Is it wrong? No. Is it useful? Also no. In the Korean payments context, "Visa" is barely the beginning of the question. Which issuer — 신한카드? 현대카드? Is it a credit card…
