Method and device for securing the reading of a memory
First Claim
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1. A method, comprising:
- selecting an address indicating a storage location of a memory;
reading a first datum from the storage location indicated by the selected address;
saving in a first storage space the first datum read from the storage location;
saving in a second storage space, associated with the first storage space, the selected address;
accessing the selected address from the second storage space;
reading a second datum from the storage location of the memory using the selected address accessed from the second storage space;
reading from the first storage space the first datum saved in the first storage space; and
activating an error signal if the second datum read from the memory is different from the first datum saved in the first storage space.
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Abstract
A method reads a datum saved in a memory by selecting an address of the memory in which the datum to be read is saved, reading the datum in the memory at the selected address, saving the datum read in a storage space, and when the memory is not being accessed by a CPU, reading the datum in the memory, reading the datum saved in the storage space, and activating an error signal if the datum read in the memory is different from the datum saved. The method can be applied particularly to the protection of smart card integrated circuits.
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Citations
18 Claims
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1. A method, comprising:
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selecting an address indicating a storage location of a memory; reading a first datum from the storage location indicated by the selected address; saving in a first storage space the first datum read from the storage location; saving in a second storage space, associated with the first storage space, the selected address; accessing the selected address from the second storage space; reading a second datum from the storage location of the memory using the selected address accessed from the second storage space; reading from the first storage space the first datum saved in the first storage space; and activating an error signal if the second datum read from the memory is different from the first datum saved in the first storage space. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A device for protecting the reading of a memory, comprising:
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a storage space configured to save a first datum read from a storage location in the memory identified by a selected address, and save the selected address in association with the first datum; means for reading a second datum from the memory by using the saved selected address; a comparator configured to compare the first datum saved in the storage space with the second datum read from the memory; and means for activating an error signal if the first datum saved is different from the second datum read from the memory. - View Dependent Claims (9, 10, 11, 12, 13)
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14. An integrated circuit, comprising:
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a central processing unit; a memory read by the central processing unit; a protection device that includes; a storage space configured to save each datum read from the memory by the central processing unit; means for checking, while the central processing unit is not accessing the memory, the data saved in the storage space, the checking including re-reading the data from the memory, comparing each datum saved in the storage space with a corresponding datum re-read from the memory, and activating an error signal if the datum saved is different from the datum re-read from the memory. - View Dependent Claims (15, 16, 17, 18)
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Specification