IC card having internal error checking capability
First Claim
1. An IC card adapted to interface with at least one terminal for performing a plurality of applications, the IC card comprising in combination:
- onboard memory means divided into a plurality of application blocks for storage of information related to the applications, some of the application blocks being of a size different from others, the memory means also having a protected block for storage of application block information including directory data and an error check code relating to each of the plurality of application blocks;
an onboard microprocessor for controlling access to the memory in such a way as to prevent access to the protected block by the terminal and to selectively allow access to the application blocks by the terminal for selectively performing the applications; and
program means for causing the microprocessor(a) to compute an error check code for a data group related to one of the plurality of applications, and to store the data group in a selected application block and the computed error check code in the protected block in the location associated with the selected application block when the data group is sent from the terminal,(b) to detect data error in the stored data group in an application block accessed from the terminal by using the data group and the error check code thereof when the data block is read out to the terminal.
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Accused Products
Abstract
An IC card particularly adapted for multiple functions and having an error checking capability which operates within the card and without the need for the processing power of the terminal. The IC card has an onboard memory and an onboard microprocessor. The onboard memory contains a plurality of application blocks to which access is selectively allowed by the microprocessor and a protected block which is accessible by the microprocessor but inaccessible by the terminal. Stored within the protected block are data specifying the location, size and application associated with each of the application blocks, as well as an error check code relating to the data then stored within the application block.
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Citations
9 Claims
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1. An IC card adapted to interface with at least one terminal for performing a plurality of applications, the IC card comprising in combination:
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onboard memory means divided into a plurality of application blocks for storage of information related to the applications, some of the application blocks being of a size different from others, the memory means also having a protected block for storage of application block information including directory data and an error check code relating to each of the plurality of application blocks; an onboard microprocessor for controlling access to the memory in such a way as to prevent access to the protected block by the terminal and to selectively allow access to the application blocks by the terminal for selectively performing the applications; and program means for causing the microprocessor (a) to compute an error check code for a data group related to one of the plurality of applications, and to store the data group in a selected application block and the computed error check code in the protected block in the location associated with the selected application block when the data group is sent from the terminal, (b) to detect data error in the stored data group in an application block accessed from the terminal by using the data group and the error check code thereof when the data block is read out to the terminal. - View Dependent Claims (2, 3, 4, 5)
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6. A method of operating a multiple application IC card, the IC card having an onboard microprocessor and an onboard memory, the method comprising the steps of
(a) partitioning the memory into a protected block and a plurality of application blocks relating to the plurality of applications, at least some of the application blocks being of a size different than others, (b) storing application block information in the protected block including directory data indicating the locations of the respective application blocks associated with an error check code relating to the data stored within the application blocks, (c) responding to a request for access to a selected application block by locating the block using the stored directory data and performing an error check on the stored data using the error check code stored in the protected block which corresponds to the selected application block, and (d) responding to an operation in which data within a selected application block is altered by performing an error check code computation on the data within the selected block and storing the error check code in the protected area in the location associated with the selected block.
Specification