AN APPARATUS, A METHOD OF OPERATING AN APPARATUS, AND A NON-TRANSITORY COMPUTER READABLE MEDIUM TO STORE COMPUTER-READABLE CODE FOR FABRICATION OF AN APPARATUS

Abstract

There is provided an apparatus provided with counter control circuitry to maintain counters associated with data items including: minor counters, middle counters, and a major counter. The apparatus is also provided with a memory protection unit configured, in response to a transfer of a data item from secure storage to off-chip storage, to modify a minor counter associated with the data item, and to encrypt the data item based on counters associated with the data item. The memory protection unit is also responsive to an overflowing minor counter, to perform a middle re-encryption process comprising modifying a middle counter associated with the data item and re-encrypting data items associated with the middle counter. The memory protection unit is also responsive to an overflowing middle counter, to perform a major re-encryption process comprising modifying the major counter, and re-encrypting each of the data items.

CPC Classifications