Python: Check Credit Card "checksum"

The CardChecksum function returns 1 for valid cards and 0 for invalid cards, after performing a check using the Luhn algorithm which validates all major credit cards.

	def CardChecksum(CardNum):
	CardSum = 0
	NumDigits = len(CardNum)
	OddOrEven = NumDigits & 1
	for DigCount in range(0, NumDigits):
	Digit = int(CardNum[DigCount])
	if not ((DigCount & 1) ^ OddOrEven):
	Digit = Digit * 2
	if Digit > 9:
	Digit = Digit - 9
	CardSum = CardSum + Digit
	return ((CardSum % 10) == 0)

view raw CardCheckSum.py hosted with ❤ by GitHub