Patent EP0274191A2 successfully refreshed from Google Patents.
EP0274191A2
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Transaction approval system
Assignee: Visa International Service Association
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Filing: 1987-10-30
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Granted: —
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Expires: 2007-10-30
Abstract
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 in respect of each invalid card is less than the actual account numbers of the respective invalid cards. By using a compressed version of the data corresponding to the account number the master table can be shortened to facilitate storage and transmission. The master table is arranged at the transaction terminal such that when an invalid card is presented, it will be identified by the data in the table and it will be routed on for further processing. In the preferred embodiment, the probability that a valid card will be identified as potentially invalid is of the order of one to three percent. The master table of the preferred embodiment comprises a plurality of bit maps into which a corresponding plurality of indicators are inserted at locations in respect of each invalid card and each bit map specified by an index value corresponds to its account number. Each bit map is provided with a different index number corresponding to a different specified algorithmic function on the respective account number, whereby the data content in the table corresponding to each account number is compressed.
Inventors
- 👤 Elvis W. Boggan
- 👤 Carl M. Campbell, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 04:17
CPC Classifications
G; G07; G07F; G07F7/00; G07F7/08; G06; G06Q; G06Q20/00; G06Q20/38; G06Q20/40; G06Q20/403
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
124 words
A transaction system including a central processor and a plurality of transaction terminals, each for verifying a plurality of transaction cards, each card having an account number, so as to identify which of said cards are invalid, said system being for facilitating off-line approval of transactions and comprising: means at said central processor for creating a master table, said master table having one or more bit maps, wherein one indicator is provided in the or 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 the or each bit map for the account number of the transaction card being presented.
Claim 2
Dependent Claim
124 words
A transaction system including a central processor and a plurality of transaction terminals, each for verifying a plurality of transaction cards, each card having an account number, so as to identify which of said cards are invalid, said system being for facilitating off-line approval of transactions and comprising: means at said central processor for creating a master table, said master table having one or more bit maps, wherein one indicator is provided in the or 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 the or each bit map for the account number of the transaction card being presented.
Claim 3
Dependent Claim
32 words
A transaction system as recited in Claim 1 wherein said means for supplying the master table to the transaction terminals comprises: a radio transmitter; and a receiver located at each transaction terminal.
Claim 4
Dependent Claim
91 words
A transaction system as recited in Claim 1 or Claim 2 wherein said means at said central processor generates said master table by selecting sets of digits from the account number of each invalid transaction card and calculating an index value for each set of digits which is an algorithmic function thereof and placing an indicator in individual bit maps at locations corresponding to the calculated index values whereby the data held by the master table in respect of each card is less than the entire account number of the card.
Claim 5
Dependent Claim
61 words
A transaction system as recited in Claims 3 wherein said transaction terminal selects sets of digits from the account number of the transaction card which has been presented and generates a set of index values and wherein said index values are used as addresses to determine if indicators are present in corresponding locations in the bit maps of the master table.
Claim 6
Dependent Claim
38 words
A transaction system as recited in any preceding claim wherein the transaction terminal allows the transaction to continue unless an indicator is present in all bit maps and in that case, the transaction is subjected to further verification.
Claim 7
Dependent Claim
45 words
A transaction system as recited in any preceding claim wherein the length of each bit map is set with respect to the number of invalid transaction cards such that the probability of an indicator being present in the bit map is approximately 0.4 to 0.5.
Claim 8
Dependent Claim
44 words
A transaction system as recited in any preceding claim wherein the number of bit maps in the master table are selected such that the probability of a valid card being represented as an invalid card in the data file is less than ten percent.
Claim 9
Dependent Claim
47 words
A transaction system as recited in Claims 7 wherein the number of bit maps in the master table are selected such that the probability of a valid card being represented as an invalid card in the data file is of the order of one to three percent.
Claim 10
Dependent Claim
38 words
A transaction system as recited in any preceding claim wherein the entire master table does not have to be scanned to determine if an indicator exists for the account number of the transaction card presented for the transaction.
Claim 11
Independent Claim
202 words
A method of identifying invalid transaction cards, of the type bearing an account number code, in the course of card authorised transactions using a transaction network which comprises a central processor, a plurality of card reading 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) defining a master table at said central processor, said table including at least a first bit map having a prescribed number (B) of locations; (b) selecting a set of digits from the account numbers 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 at a location corresponding to said first index value; (e) repeating steps (b) through (d) for each invalid card; and (f) supplying the master table when compiled as in steps (b) through (e) 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.
Claim 12
Independent Claim
202 words
A method of identifying invalid transaction cards, of the type bearing an account number code, in the course of card authorised transactions using a transaction network which comprises a central processor, a plurality of card reading 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) defining a master table at said central processor, said table including at least a first bit map having a prescribed number (B) of locations; (b) selecting a set of digits from the account numbers 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 at a location corresponding to said first index value; (e) repeating steps (b) through (d) for each invalid card; and (f) supplying the master table when compiled as in steps (b) through (e) 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.
Claim 13
Dependent Claim
82 words
A method as recited in Claim 10 further including the steps at the transaction terminal of: repeating steps (b) and (c) for the account number of a card presented thereto so as to generate a first index value corresponding to that card; determining if an indicator is present in the first bit map at a location corresponding to the generated first index value; and allowing the transaction to continue unless an indicator is present whereupon the transaction is subjected to further verification.
Claim 14
Dependent Claim
143 words
A method according to Claim 11 wherein said master table defines a plurality of bit maps, each having the same number (B) of locations, 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, repeating this process for each invalid card, repeating steps (b) and (c) at the transaction terminal for each bit map for the account number of a card presented thereto so as to generate a plurality of values corresponding to that card, determining if indicators are present in each bit map corresponding to the generated values, and allowing the transaction to continue unless a said corresponding indicator is present in each bit map whereupon the transaction is subjected to further verification.
Claim 15
Dependent Claim
41 words
A method according to Claim 12 wherein said master table generated at said central processor includes data derived from a plurality of invalid transaction cards which is less than the data corresponding to the entire account number of all the cards.
References Cited (Backward Citations)
No citation records indexed.
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