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AssigneeSilverbrook Research Pty Ltd
InventorsKia Silverbrook, Simon Robert Walmsley
Estimating the term…
The invention is a method and system in which an authentication chip having secret information stored within it, including secret data stored in multi-level flash memory, is protected from unauthorized modification of values stored in the flash memory. The secret information is stored using an internal command and can only be accessed by one or more further commands. Secret data in the information is stored in intermediate states of the multilevel flash memory between the minimum and maximum voltage level states. A validity check is performed on secret data items before allowing them to be read out by a command accessing them. The validity check involves calculation of a checksum and comparison of the result with a checksum stored using the internal command as part of the secret information.
In an authentication chip having secret information stored within it, including secret data and non sensitive data stored in multi-level flash memory, the multi-level flash memory having invalid and valid (intermediate) voltage stages, a method of protecting the authentication chip from unauthorised modification of values stored in the flash memory, the method including the steps of:
An authentication system including a chip having secret information stored within it using an internal command, the secret information including secret data stored in multi-level flash memory, and a checksum for the data, the multi-level flash memory also storing non-sensitive data where the secret information can only be accessed by one or more further commands, the secret data is stored in intermediate (valid) states of the multi-level flash memory between the minimum and maximum voltage level states which are invalid states, and a data validity check is performed on secret data items before allowing the data items to be read out by a command accessing them, the validity check involving calculation of a checksum and comparison of the result with the checksum stored using the internal command and wherein data validity checks are performed on non-sensitive information to detect invalid states in the multi-level flash memory.
Dependencies are inferred from the claim text.