# US 12,603,769 B2 · Time-coordinated address rotation

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 12,603,769 B2
- Document ID: US12603769B2
- Status: Granted
- Kind: B2
- Application number: 18/607,005
- Filed: 2024-03-15
- Published: 2025-07-03
- Granted: 2026-04-14
- Earliest claimed: 2023-12-27
- Assignees: Cisco Technology, Inc.
- Applicants: Cisco Technology, Inc.
- Inventors: Ugo Campiglio; Domenico Ficara; Jerome Henry; Amine Choukir; Javier Contreras
- Web page: https://patentgrep.com/patent/US12603769B2

## CPC

- H04L 9/0869: {involving random numbers or seeds}
- H04L 9/085: {Secret sharing or secret splitting, e.g. threshold schemes}
- H04L 9/0866: {involving user or device identifiers, e.g. serial number, physical or biometrical information, DNA, hand-signature or measurable physical characteristics}
- H04L 9/0872: {using geo-location information, e.g. location data, time, relative position or proximity to other entities}
- H04L 9/3297: {involving time stamps, e.g. generation of time stamps}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

Devices, networks, systems, methods, and processes for rotating a Media Access Control (MAC) address of a device. A device can negotiate a periodicity for address rotation of the MAC address associated with the device. The device may receive a data frame and generate seed data based on the data frame. The device can also utilize a shared secret key, a cryptographic hash function, and/or a cryptographically secure pseudorandom number generator to generate the seed data. The device can determine timestamp data based on the periodicity or a time of reception of the data frame. The device may utilize a pseudorandom function to determine the MAC address based on the timestamp data and the seed data. The device can generate the MAC address after every rotation cycle. Upon waking up from a power saving mode, the device can synchronize with a network device to generate next MAC address.

## Claims

### Claim 1

A device, comprising:
a processor;
a memory communicatively coupled to the processor; and
an address rotation logic, configured to:
determine a periodicity of address rotation for a wireless device;
initiate a timer based on the periodicity;
determine, upon expiration of the timer, seed data and timestamp data indicative of a time of transmission;
apply a pseudorandom function on the seed data and the timestamp data to generate a Media Access Control (MAC) address; and
transmit a data frame to the wireless device.

### Claim 2 (depends on 1)

The device of claim 1, wherein the address rotation logic is further configured to;
receive the data frame from the wireless device.

### Claim 3 (depends on 2)

The device of claim 2, wherein the timestamp data is indicative of a time of transmission or reception of the data frame.

### Claim 4 (depends on 2)

The device of claim 2, wherein the timestamp data is indicative of a time of expiration of the timer.

### Claim 5 (depends on 4)

The device of claim 4, wherein the address rotation logic is further configured to:
decrypt the data frame to generate a decrypted data frame;
determine a predetermined number of bits of the decrypted data frame; and
generate the seed data based on the predetermined number of bits.

### Claim 6 (depends on 5)

The device of claim 5, wherein the address rotation logic is further configured to determine the predetermined number of bits based on a key size of the pseudorandom function.

### Claim 7 (depends on 1)

The device of claim 1, wherein the address rotation logic is further configured to:
initialize a cryptographically secure pseudorandom number generator;
generate random number data based on the cryptographically secure pseudorandom number generator; and
generate the seed data based on the random number data.

### Claim 8 (depends on 1)

The device of claim 1, wherein the address rotation logic is further configured to:
determine a shared secret key associated with the wireless device; and
generate the seed data based on the shared secret key.

### Claim 9 (depends on 8)

The device of claim 8, wherein the address rotation logic is further configured to apply a cryptographic hash function on the timestamp data and the shared secret key to generate the MAC address.

### Claim 10 (depends on 1)

The device of claim 1, wherein the address rotation logic is further configured to reinitiate the timer after generating the MAC address.

### Claim 11 (depends on 1)

The device of claim 1, wherein the address rotation logic is further configured to:
operate in a sleep mode;
transmit a synchronization request upon switching from the sleep mode to an operational mode;
receive a synchronization response in response to the synchronization request; and
determine the MAC address based on the synchronization response.

### Claim 12 (depends on 11)

The device of claim 11, wherein the synchronization request is at least one of:
a null data frame; or
a Target Wake Time (TWT) request frame.

### Claim 13 (depends on 11)

The device of claim 11, wherein the address rotation logic is further configured to receive a plurality of data frames in the sleep mode based on a previous MAC address.

### Claim 14 (depends on 1)

The device of claim 1, wherein, after a period of time indicated by the periodicity, the timer expires or reinitializes.

### Claim 15

A device, comprising:
a processor;
a memory communicatively coupled to the processor; and
an address rotation logic, configured to:
determine a periodicity of address rotation for a wireless device;
receive a data frame from the wireless device;
determine timestamp data based on the periodicity or the data frame;
generate a Media Access Control (MAC) address based on the timestamp data and the data frame;
decrypt the data frame to generate a decrypted data frame;
determine a predetermined number of bits of the decrypted data frame;
generate seed data based on the predetermined number of bits; and
apply a pseudorandom function on the seed data and the timestamp data to generate the MAC address.

### Claim 16 (depends on 15)

The device of claim 15, wherein the address rotation logic is further configured to:
determine a shared secret key associated with the wireless device; and
apply a cryptographic hash function on the timestamp data and the shared secret key to generate the MAC address.

### Claim 17

A method, comprising:
determining a periodicity of address rotation for a wireless device;
initiating a timer based on the periodicity;
determining, upon expiration of the timer, seed data and timestamp data;
applying a pseudorandom function on the seed data and the timestamp data to generate a Media Access Control (MAC) address:
receiving a data frame from the wireless device;
determining the seed data based on the data frame; and
determining the timestamp data based on the timer or the data frame.

### Claim 18

A device, comprising:
a processor;
a memory communicatively coupled to the processor; and
an address rotation logic, configured to:
determine a periodicity of address rotation for a wireless device;
initiate a timer based on the periodicity;
determine, upon expiration of the timer, seed data and timestamp data indicative of a reception of a data frame;
apply a pseudorandom function on the seed data and the timestamp data to generate a Media Access Control (MAC) address; and
receive the data frame from the wireless device.