Control system having download function
First Claim
1. A control system in communication with a host control system and having a download function, comprising:
- a first storage element storing execution program data to execute a control function in a rewritable status;
a second storage element to store a download module including fresh pieces of update target execution program data and module identifying information;
a first control unit receive the download module encrypted in the host control system by an encryption key generated from the same program data as the execution program data stored in said first storage element and from the module identifying information, and to store the received download module in said second storage element; and
a second control unit to decrypt the download module by an encryption key generated in the control system itself from the execution program data in said first storage element and from the module identifying information of the download module in said second storage element and to replace, when a storage start address, a data length and a check digit that are encrypted in the download module are decrypted into valid values in a plain text, the execution program data in said first storage element with the fresh execution program data decrypted.
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Accused Products
Abstract
A control system having a download function includes a first storage area for storing execution program data for executing a control function in a rewritable status, a second storage area for storing a download module containing fresh pieces of update target execution program data and module identifying information, a first control unit for receiving the download module encrypted by an encryption key generated from the same program data as the execution program data stored in the first storage element and from the module identifying information, and storing the received download module in the second storage element, and a second control unit for decrypting the download module by an encryption key generated from data in the execution program data in the first storage area and from data of the download module in the second storage area and replacing, when a storage start address, a data length and a check digit that are encrypted in the download module are decrypted into valid values in a plain text, the execution program data in the first storage area with the fresh execution program data decrypted.
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Citations
20 Claims
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1. A control system in communication with a host control system and having a download function, comprising:
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a first storage element storing execution program data to execute a control function in a rewritable status; a second storage element to store a download module including fresh pieces of update target execution program data and module identifying information; a first control unit receive the download module encrypted in the host control system by an encryption key generated from the same program data as the execution program data stored in said first storage element and from the module identifying information, and to store the received download module in said second storage element; and a second control unit to decrypt the download module by an encryption key generated in the control system itself from the execution program data in said first storage element and from the module identifying information of the download module in said second storage element and to replace, when a storage start address, a data length and a check digit that are encrypted in the download module are decrypted into valid values in a plain text, the execution program data in said first storage element with the fresh execution program data decrypted. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A download control method of a control system, comprising:
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storing a first storage element with execution program data for executing a control function in a rewritable status; storing a second storage element with a download module including fresh pieces of update target execution program data and module identifying information; receiving the download module encrypted in a host control system by an encryption key generated from the same program data as the execution program data stored in said first storage element and from the module identifying information, and storing the received download module in said second storage element; and decrypting the download module by an encryption key generated in the control system itself from the execution program data in said first storage element and from the module identifying information of the download module in said second storage element and replacing, when a storage start address, a data length and a check digit that are encrypted in the download module are decrypted into valid values in a plain text, the execution program data in said first storage element with the fresh execution program data decrypted. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification