Oyster card is a payment card issued by Transport for London for public transport within its network. Every Oyster card has a unique number on its back.
The number is in the format of 10 digits, followed by a checksum of 2 digits, both of which may include leading zeros, for example, 0000000000 00.
With some experiments, I found the checksum can be calculated with the following formula:
1 2 3 4 5 6 7 8 9 10 11 def checksum(number: int) -> int: return ( + number 0x10 + number // 0x1 3 - number // 0x10 3 + number // 0x100 3 - number // 0x1000 3 + number // 0x10000 3 - number // 0x100000 3 + number // 0x1000000 3 - number // 0x10000000 *
Tilllawrence2020
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1 month ago
Oyster card checksum - SEIAROTg's blog
Oyster card is a payment card issued by Transport for London for public transport within its network. Every Oyster card has a unique number on its back. The number is in the format of 10 digits, followed by a checksum of 2 digits, both of which may include leading zeros, for example, 0000000000 00. With some experiments, I found the checksum can be calculated with the following formula: 1 2 3 4 5 6 7 8 9 10 11 def checksum(number: int) -> int: return ( + number 0x10 + number // 0x1 3 - number // 0x10 3 + number // 0x100 3 - number // 0x1000 3 + number // 0x10000 3 - number // 0x100000 3 + number // 0x1000000 3 - number // 0x10000000 *
https://seiarotg.me/post/oyster-card-checksum/