Non-volatile memory device and method of writing to non-volatile memory device
A non-volatile memory device includes: a memory group of a plurality of variable resistance memory cells in which digital data is recorded according to a magnitude of a resistance value, the memory group including at least one data cell and at least one dummy cell which are associated with each other; and a read circuit which performs, in parallel, a read operation on each of the plurality of memory cells included in the memory group. Dummy data, for reducing a correlation between a side-channel leakage generated when the read operation is performed by the read circuit and information data recorded in the at least one data cell, is recorded in the at least one dummy cell.
1. A non-volatile memory device, comprising:
a memory group of a plurality of memory cells in which digital data is recorded according to a magnitude of a resistance value, the memory group including at least one data cell and at least one dummy cell which are associated with each other, the plurality of memory cells being variable resistance memory cells;
a read circuit which performs, in parallel, a read operation on each of the plurality of memory cells included in the memory group,
wherein dummy data is recorded in the at least one dummy cell, the dummy data being for reducing a correlation between a side-channel leakage and information data recorded in the at least one data cell, the side-channel leakage being generated when the read operation is performed by the read circuit.
2. The non-volatile memory device according to claim 1 , further comprising:
a write circuit which performs a write operation for writing the dummy data on the at least one dummy cell, based on the information data recorded in the at least one data cell.
3. The non-volatile memory device according to claim 1 ,
wherein physically unclonable function (PUF) data is recorded in the plurality of memory cells, the PUF data being device-specific data in which variations in physical characteristics are used.
4. The non-volatile memory device according to claim 3 ,
wherein the plurality of memory cells include a plurality of variable memory cells each of which is a memory cell in a variable state where a resistance value reversibly changes between a plurality of variable resistance value ranges in response to an application of a plurality of electric signals which are mutually different, and
resistance value variations of the plurality of variable memory cells in a same resistance state are used as the variations in physical characteristics used in the PUF data.
5. The non-volatile memory device according to claim 3 ,
wherein the plurality of memory cells include:
a variable memory cell which is a memory cell in a variable state where a resistance value reversibly changes between a plurality of variable resistance value ranges in response to an application of a plurality of electric signals which are mutually different; and
a memory cell in an initial state where the memory cell does not change to the variable state unless a forming stress is applied, the initial state being in an initial resistance range in which a resistance value does not overlap any of the plurality of variable resistance value ranges, the forming stress being an electric stress which changes the memory cell to the variable state,
wherein variations in a cumulative pulse time period necessary for the forming stress are used as the variations in physical characteristics used in the PUF data.
6. The non-volatile memory device according to claim 3 ,
wherein the PUF data is recorded in the at least one data cell, and
error correction data of the PUF data is not recorded in the plurality of memory cells included in the memory group.
7. The non-volatile memory device according to claim 1 ,
wherein the dummy data is data for setting a Hamming weight of the at least one data cell and the at least one dummy cell to a predetermined value.
8. The non-volatile memory device according to claim 1 ,
wherein the dummy data is random number data.
9. The non-volatile memory device according to claim 6 ,
wherein the plurality of memory cells include a variable memory cell which is a memory cell in a variable state where a resistance value reversibly changes between a plurality of variable resistance value ranges in response to an application of a plurality of electric signals which are mutually different,
the at least one dummy cell is the variable memory cell, and
the dummy data is a resistance value in a same resistance state.
10. A method of writing to a non-volatile memory device including: a memory group of a plurality of memory cells in which digital data is recorded according to a magnitude of a resistance value, the memory group including at least one data cell and at least one dummy cell which are associated with each other, the plurality of memory cells being variable resistance memory cells; and a read circuit which performs, in parallel, a read operation on each of the plurality of memory cells, the method comprising:
writing dummy data to the at least one dummy cell, the dummy data being for reducing a correlation between a side-channel leakage and information data recorded in the at least one data cell, the side-channel leakage being generated when the read operation is performed by the read circuit.