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This library makes use of Luhn’s algorithm to check the card’s validity and authenticity.
Below the methods that are of use:
initWithString:(NSString *)string:
Use this to init the class with the card number

lengthForCardType:

returns the length of the card number for the  specified card.

cardType:

 returns the card type

formattedStringWithTrail:
returns the card number in a formatted format including relevant spaces in between according to the card type.(with a trail)

formattedString:
returns the card number in a formatted format including relevant spaces in between according to the card type.

isValidLength:
checks if the length of the card is valid or not

isValidLuhn:
checks if the card is validating using the Luhn’s algorithm

isPartiallyValid:
returns YES if the card partially satisfies any of th above categories.

isValid:
checks for both length and Luhn’s validation for the card