Account file for off-line transaction authorization
AssigneeVisa International Service Association
InventorCarl M. Campbell, Jr.
Life of this patent
Estimating the term…
Abstract
An approach for handling data representative of invalid transaction cards is disclosed. A memory area 34 in a transaction terminal 16 is divided into a plurality of stacks. Two digits of the invalid account number are used to identify the stack into which the remainder of the account number is added. Stack start pointers are provided for file management. As the newest entries are added to the list, the oldest entries are purged. The subject system allows a large number of accounts to be stored in a minimum of space. Updates of the file can be easily handled during direct communication sessions between a central processor 12 and the terminal 16.
Claims17
A system for representing invalid transaction card account numbers in a credit card transaction network, said network including a central processor, and a merchant location including at least one transaction terminal for storing a list of invalid transaction card account numbers, said system comprising:
- means for truncating a transaction card account number in said central processor to create a hashed number representing an invalid transaction card account, wherein said hashed number is smaller in length than said transaction card account number;
- means for transmitting said hashed number from said central processor to said transaction terminal thereby transmitting a lesser number of digits to said transaction terminal, said transaction terminal including
- memory means partitioned into a plurality of stacks, each of said stacks including a plurality of addressed locations wherein each of said addressed locations stores a first identifying number representing an invalid transaction card account number, and
- processor means including means for truncating a predetermined length from said hashed number to create a second identifying number and a truncated number where said second identifying number represents said transaction card account number and said truncated number identifies a particular one of said stacks in which said first identifying number matching said second identifying number may be present, said processor means including means for selecting from said stacks using said truncated number a selected stack in which to store said second identifying number which is smaller in length than said hashed number when said first identifying number is not present.
A system for representing invalid transaction card account numbers in a transaction card transaction network, said network including a central processor, a transaction card issuer connected to said central processor, and a merchant location including at least one transaction terminal and processor means connected to said central processor for storing a list of invalid transaction card account numbers, said system comprising:
- means for transmitting a transaction card account number from said issuer to said central processor;
- means for truncating said transaction card account number in said central processor to create a hashed number representing an invalid transaction card account where said hashed number smaller in length than said transaction card account number;
- means for transmitting said hashed number from said central processor to said transaction terminal thereby transmitting a lesser number of digits to said transaction terminal, said transaction terminal including
- memory means partitioned into a plurality of stacks, each of said stacks including a plurality of addressed locations, wherein each of said addressed locations stores a first identifying number representing an invalid transaction card account number, and
- processor means including means for truncating said hashed number to create a second identifying number and a truncated number where said second identifying number represents said transaction card account number and said truncated number identifies a particular one of said stacks in which said first identifying number matching said second identifying number may be present, said processor means including means for selecting from said stacks using said truncated number a selected stack in which to store said second identifying number which is smaller in length than said hashed number when said first identifying number is not present.
A method of representing invalid transaction card account numbers for off-line transaction authorization in a transaction card transaction network, said network including a central processor, a transaction card issuer connected with said central processor, and a merchant location including at least one transaction terminal including a processor means connected to said central processor, said method comprising the steps of:
- transmitting an invalid transaction card account number from a transaction card issuer to said central processor;
- truncating said invalid transaction card account number in said central processor whereby said invalid transaction card account number is reduced in size and a smaller hashed number is created;
- transmitting said smaller hashed number from said central processor to said transaction terminal;
- partitioning said memory means in said transaction terminal into a plurality of stacks, each of said stacks including a plurality of addressed locations, wherein each of said addressed locations stores a first identifying number representing an invalid transaction card account number;
- truncating said hashed number in said transaction terminal processing means to provide a second identifying number and a truncated number, wherein said second identifying number represents said invalid transaction card account number and said truncated number identifies a particular one of said stacks in which said first identifying number matching said second identifying number may be present;
- searching said one of said stacks indicated by said truncated number by said processor means for said first identifying number matching said second identifying number;
- and
- storing said second identifying number, which is smaller in length than said hashed number, in said one of said stacks indicated by said truncated number when said first identifying number matching said second identifying number is not found.
Dependencies are inferred from the claim text.