When the card is generating arqc algorithm, does card number play any role ? In other words: having 2 brand new cards with ATC set to 0 and having the same CDOL, will they generate the same arqc ?
1 Answers
2
votes
Card number and ATC are involved in session key generation. So every card will generate a different cryptogram.
Since I am not sure whether you are referring to the same card number (Assuming you were able to clone a card :) Still the cryptogram generated will be different for your first try for your both cards . If you look for CDOL, you can see an element unpredictable number( which is generated by terminal ). This is a 4 byte numeric field and chance of getting this generated same twice is very rare. Even in case where unpredictable number is same, still you need all other elements in CDOL same (amount, currency, country date atc etc) to get the same cryptogram. To block even this rare possibility issuers maintain the last used ATC for each card that it will not accept any ATC same or less. Hope it is clear.
