Transaction approval system
First Claim
1. In a transaction network including a central processor, a plurality of transaction terminals and a plurality of transaction cards, each card having an account number associated therewith, a method for identifying invalid cards comprising the steps of:
- (a) generating a master table at said central processor, said table including at least a first bit map B bits in length;
(b) selecting a set of digits from the account number of a first invalid transaction card;
(c) calculating a first index value which is an algorithmic function of said set of digits, said first index value being between zero and B-1;
(d) placing an indicator within said first bit map corresponding to said first index value;
(e) repeating steps b though d for each invalid card; and
(f) supplying the master table to each transaction terminal whereby during a transaction, the transaction terminal determines if an indicator exists in the master table corresponding to the account number of the card presented for the transaction.
1 Assignment
0 Petitions
Accused Products
Abstract
An improved system is disclosed for detecting invalid transaction cards at remote transaction terminals. The system includes providing each terminal with a master table having data corresponding to invalid cards. The data in the master table is less than the actual account numbers of the invalid cards. By using a compressed version of the data, the file can be shortened to facilitate storage and transmission. The compressed data file is arranged such that when an invalid card is presented, it will be identified and routed on for further processing. In the preferred embodiment, the probability that a valid card will be identified as potentially invalid is on the order of one of three percent.
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Citations
29 Claims
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1. In a transaction network including a central processor, a plurality of transaction terminals and a plurality of transaction cards, each card having an account number associated therewith, a method for identifying invalid cards comprising the steps of:
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(a) generating a master table at said central processor, said table including at least a first bit map B bits in length; (b) selecting a set of digits from the account number of a first invalid transaction card; (c) calculating a first index value which is an algorithmic function of said set of digits, said first index value being between zero and B-1; (d) placing an indicator within said first bit map corresponding to said first index value; (e) repeating steps b though d for each invalid card; and (f) supplying the master table to each transaction terminal whereby during a transaction, the transaction terminal determines if an indicator exists in the master table corresponding to the account number of the card presented for the transaction. - View Dependent Claims (2, 3)
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4. In a transaction network including a central processor, a plurality of transaction terminals and a plurality of transaction cards, each card having an account number associated therewith, a method for identifying invalid cards comprising the steps of:
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(a) generating a master table at said central processor, said table including a plurality of bit maps, each map being B bits in length; (b) selecting a set of digits from the account number of a first invalid transaction card; (c) calculating a first index value which is an algorithmic function of said set of digits, said first index value being between zero and B-1; (d) placing an indicator within one of said bit maps, said indicator corresponding to said first index value; (e) repeating steps b and c for each bit map in said master table, each time selecting a unique set of digits from the account number and placing an indicator corresponding to each calculated value in the associated bit map; (f) repeating steps b though e for each invalid card; and (g) supplying the master table to each transaction terminal whereby during a transaction, the transaction terminal determines if an indicator exists in the master table corresponding to the account number of the card presented for the transaction. - View Dependent Claims (5, 6)
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7. In a transaction network including a central processor, a plurality of transaction terminals and a plurality of transaction cards, each card having an account number associated therewith, a method for identifying invalid cards comprising the steps of:
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(a) generating a master table at said central processor, said table including data derived from a list of invalid transaction cards, said data being less than the entire account number of each card and including at least one indicator for each invalid card; and (b) supplying the master table to each transaction terminal whereby during a transaction, the transaction terminal determines if an indicator exists in the master table for the account number of the card presented for the transaction and allowing the transaction to continue unless an indicator is present whereupon the transaction will be subjected to further verification. - View Dependent Claims (8)
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9. A data file for use in transaction networks, said data file including information about the account numbers of invalid transaction cards comprising:
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a master table including a plurality of bit maps each having B bits; and one indicator in each bit map for each invalid card, each said indicator being at a location corresponding to an index value which is an algorithmic function of a set of digits in the account number of the transaction card. - View Dependent Claims (10, 11, 12)
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13. A transaction system including a central processor and a plurality of transaction terminals and a plurality of transaction cards each having an account number, and with some of said cards being invalid, said system for facilitating off line approval of transactions comprising:
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means at said central processor for creating a master table, said master table having a plurality of bit maps, wherein one indicator is provided in each bit map for each invalid transaction card; means for supplying the master table to each of the transaction terminals; and means at each transaction terminal for determining if an indicator is present in each bit map for the account number of the transaction card being presented. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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21. A financial transaction system including a central processor and a plurality of transaction terminals and a plurality of transaction cards each having an account number, and with some of said cards being invalid, said system for facilitating off-line approval of transactions comprising:
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means at said central processor for creating a master table, said master table having data derived from a list of invalid transaction cards, said data being less than the entire account number of each card and including at least one indicator for each invalid transaction card; means for supplying the master table to each of the transaction terminals; and means at each transaction terminal for determining if an indicator exists in the master table for the account number of the transaction card being presented and allowing the transaction to continue if no indicator is present and subjecting the transaction to further verification if an indicator is present. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29)
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Specification