# US 2021/0243042 A1 · Security device for generating masking data based on physically unclonable function and operating method thereof

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- Number: US 2021/0243042 A1
- Document ID: US20210243042A1
- Status: Published application
- Kind: A1
- Application number: 17/020,287
- Filed: 2020-09-14
- Published: 2021-08-05
- Earliest claimed: 2020-01-30
- Assignees: Samsung Electronics Co., Ltd.
- Applicants: Samsung Electronics Co., Ltd.
- Inventors: Kyoungmoon Ahn; Yongki Lee; Yongsoo Kim
- Web page: https://patentgrep.com/patent/US20210243042A1

## CPC

- H04L 9/3278: {using physically unclonable functions [PUF]}
- H04L 9/0866: {involving user or device identifiers, e.g. serial number, physical or biometrical information, DNA, hand-signature or measurable physical characteristics}
- H04L 2209/04: Masking or blinding
- H04L 2209/12: Details relating to cryptographic hardware or logic circuitry
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A security device and an operating method thereof, which generate masking data for masking a key on the basis of a physically unclonable function (PUF), are provided. The security device includes a PUF circuit including a plurality of PUF cells outputting random key data and masking data, a key generator configured to generate a key through post-processing performed on the random key data, and a masking module configured to mask and store the key by using the masking data, wherein the random key data and the masking data are generated by different PUF cells.

## Claims

### Claim 1

A security device comprising:
a physically unclonable function (PUF) circuit including a plurality of PUF cells outputting random key data and masking data;
a key generator configured to generate a key through post-processing performed on the random key data; and
a masking module configured to mask and store the key by using the masking data,
wherein the random key data is generated from a first set of one or more PUF cells, and the masking data is generated from a different, second set of one or more PUF cells.

### Claim 2 (depends on 1)

The security device of claim 1, wherein the PUF circuit comprises a first area including a plurality of first PUF cells and a second area including a plurality of second PUF cells and differing from the first area,
wherein the random key data is generated from the first set of one or more PUF cells, which are part of the plurality of first PUF cells, and
wherein the masking data is generated from the second set of one or more PUF cells, which are part of the plurality of second PUF cells.

### Claim 3 (depends on 1)

The security device of claim 1, wherein the PUF circuit comprises a first area including a plurality of first PUF cells and a second area including a plurality of second PUF cells and differing from the first area,
wherein the random key data is generated from the first set of one or more PUF cells, which are part of the plurality of first PUF cells, and
wherein the masking data is generated from at least some of the plurality of first PUF cells and at least some of the plurality of second PUF cells, which together form the second set of one or more PUF cells.

### Claim 4 (depends on 1)

The security device of claim 1, further comprising a validity detector configured to determine the validity or not of the plurality of PUF cells and to generate a determination result as a validity map.

### Claim 5 (depends on 4)

The security device of claim 4, wherein the PUF circuit is configured to access the validity map generated by the validity detector, generate the random key data from stable PUF cells, and generate the masking data from unstable PUF cells, based on the validity map.

### Claim 6 (depends on 4)

The security device of claim 4, wherein the PUF circuit is configured to access the validity map generated by the validity detector, generate the random key data from stable PUF cells, and generate the masking data from at least some of the plurality of PUF cells, based on the validity map.

### Claim 7 (depends on 1)

The security device of claim 1, wherein the PUF circuit is configured to receive an area selection signal and to generate the masking data from PUF cells, included in an area selected based on the area selection signal, among the plurality of PUF cells.

### Claim 8 (depends on 1)

The security device of claim 1, wherein:
the masking module comprises:
a masking circuit configured to receive the key from the key generator and generate a masked key from the key and the masking data;
a key buffer configured to store the masked key; and
a restoration circuit configured to restore the masked key to the key by using the masking data.

### Claim 9 (depends on 8)

The security device of claim 8, wherein:
the masking circuit is configured to generate the masked key through an XOR operation performed on the key and the masking data, and
the restoration circuit is configured to restore the key through an XOR operation performed on the masked key and the masking data.

### Claim 10 (depends on 1)

The security device of claim 1, wherein the masking module is configured to generate new masking data by combining the masking data with a preset bit and to mask the key by using the new masking data.

### Claim 11 (depends on 1)

The security device of claim 1, wherein the masking module is configured to generate new masking data by deleting at least some bits of the masking data and to mask the key by using the new masking data.

### Claim 12 (depends on 1)

The security device of claim 1, wherein the security device is included in an electronic device that includes one or more integrated circuits.

### Claim 13

A method of generating a security key by using a physically unclonable function (PUF) circuit including a plurality of PUF cells, the method comprising:
generating random key data by using a set of first PUF cells including at least one first PUF cell included in the PUF circuit;
generating a key through post-processing performed on the random key data;
generating masking data by using a set of second PUF cells including at least one second PUF cell included in the PUF circuit;
masking the key by using the masking data to generate a masked key; and
storing the masked key in a key buffer.

### Claim 14 (depends on 13)

The method of claim 13, wherein the at least one first PUF cell is included in a first area of the PUF circuit, and the at least one second PUF cell is included in a second area, differing from the first area, of the PUF circuit.

### Claim 15 (depends on 13)

The method of claim 13, wherein the at least one first PUF cell is included in a first area of the PUF circuit, and the at least one second PUF cell is included in a second area of the PUF circuit, and
the first area is included in the second area.

### Claim 16 (depends on 13)

The method of claim 13, further comprising:
determining the validity or not of the plurality of PUF cells included in the PUF circuit; and
generating a determination result as a validity map.

### Claim 17 (depends on 16)

The method of claim 16, wherein the at least one first PUF cell comprises cells which are determined as stable cells, which are reflected in the validity map, and the at least one second PUF cell comprises cells which are determined as unstable cells, which are reflected in the validity map.

### Claim 18 (depends on 13)

The method of claim 13, further comprising:
generating the masked key through an XOR operation performed on the key and the masking data; and
restoring the key through an XOR operation performed on the masking data and the masked key.

### Claim 19 (depends on 13)

The method of claim 13, wherein the generating of the masking data comprises:
combining the masking data with a preset bit; and
outputting data, generated based on the combining, as the masking data.

### Claim 20

A security device comprising:
a physically unclonable function (PUF) block including a plurality of PUF cells outputting random key data and masking data;
a validity detector configured to determine the validity or not of the plurality of PUF cells and to generate a validity map on the basis of a result of the determination;
a key generator configured to generate a key through post-processing performed on the random key data; and
a masking module configured to mask and store the key by using the masking data,
wherein the PUF block is configured to generate the masking data on the basis of the validity map.

### Claim at position 21

21-24. (canceled)