Hi, today casually I discovered that I can authorize debit card payments by POS using only first 4 digits of the 5 digits "official" PIN . Doing some research I found article suggesting that, to make PINs portable to different systems, they use a workaround based on padding or truncation, so, for example, having 12345 as assigned PIN also valid variations are: 012345, 123450, 001234, 123400 and 1234 , if I understood correctly. See:

https://www.quora.com/What-if-the-ATM-asks-for-a-6-digit-PIN-but-your-cards-only-have-4-digit-PINs

https://together.bunq.com/d/396-pin-number-with-more-than-4-digits

Please correct me if I'm wrong. I'm very grateful is someone can point me to the related standard code (ISO, etc) or documentation. Kind regards.