# US 2023/0056352 A1 · Physical channel encryption using secret keys > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0056352 A1 - Document ID: US20230056352A1 - Status: Published application - Kind: A1 - Application number: 17/445,671 - Filed: 2021-08-23 - Published: 2023-02-23 - Earliest claimed: 2021-08-23 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Ahmed ELSHAFIE; Hung Dinh LY; Soo Bum LEE - Web page: https://patentgrep.com/patent/US20230056352A1 ## CPC - H04W 12/03: Protecting confidentiality, e.g. by encryption - H04W 12/0431: Key distribution or pre-distribution; Key agreement - H04L 63/16: {Implementing security features at a particular protocol layer} - H04W 12/033: of the user plane, e.g. user's traffic - H04W 12/041: Key generation or derivation - H04W 12/73: Access point logical identity - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may determine, based at least in part on a key derivation function and a set of physical layer parameters, a secret key for encrypting a unicast physical channel at a physical layer, wherein the secret key is a UE-specific secret key. The UE may transmit, to a base station, an encrypted transmission over the unicast physical channel based at least in part on the secret key. Numerous other aspects are described. ## Claims ### Claim 1 An apparatus for wireless communication at a user equipment (UE), comprising: a memory; and one or more processors, coupled to the memory, configured to: determine, based at least in part on a key derivation function and a set of physical layer parameters, a secret key for encrypting a unicast physical channel at a physical layer, wherein the secret key is a UE-specific secret key; and transmit, to a base station, an encrypted transmission over the unicast physical channel based at least in part on the secret key. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the one or more processors, to determine the secret key, are configured to determine the secret key based at least in part on the key derivation function, a long term key, a time value based at least in part on a key refresh interval and a current time, an identifier associated with the base station, and the set of physical layer parameters. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein determining the secret key comprises determining the secret key based at least in part on the key derivation function, a broadcast root key, and the set of physical layer parameters, wherein the broadcast root key is based at least in part on the key derivation function, a long term key, and a time value based at least in part on a key refresh interval and a current time. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein determining the secret key comprises determining the secret key based at least in part on the key derivation function, a radio access network (RAN) node specific key, and the set of physical layer parameters, wherein the RAN node specific key is based at least in part on the key derivation function, a broadcast root key, and an identifier of the base station received in a synchronization signal block. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the set of physical layer parameters include one or more of: a cell identifier, transmission configuration indicator state information indicated for receiving or transmitting the unicast physical channel, a scrambling identifier for generating a demodulation reference signal for the unicast physical channel, a zone identifier, positioning information, or an active bandwidth part (BWP) configuration that indicates a BWP index and a BWP bandwidth. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the set of physical layer parameters include transmission configuration indicator state information, and wherein the one or more processors are further configured to determine the secret key based at least in part on a resource identifier or a resource set identifier of a reference signal that functions as a source of a quasi co-location for the unicast physical channel, wherein the resource identifier or the resource set identifier includes a synchronization signal block index, a channel state information reference signal resource identifier, or a sounding reference signal resource identifier. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the set of physical layer parameters include transmission configuration indicator state information, and wherein the one or more processors are further configured to determine the secret key based at least in part on a quasi co-location (QCL) type, wherein the QCL type is associated with a key reference that is used as an input to the key derivation function. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein the set of physical layer parameters is common for a plurality of unicast physical channels. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein the set of physical layer parameters includes at least one parameter that is different from at least one other parameter between a plurality of unicast physical channels, wherein the set of physical layer parameters includes, for a physical uplink control channel, a control resource identifier, a control resource set identifier, and a timing advance command, and wherein the set of physical layer parameters includes, for a physical downlink control channel, a control channel monitoring configuration. ### Claim 10 (depends on 1) The apparatus of claim 1, wherein the one or more processors are further configured to: receive, from the base station, an indication of the set of physical layer parameters. ### Claim 11 An apparatus for wireless communication at a base station, comprising: a memory; and one or more processors, coupled to the memory, configured to: determine, based at least in part on a key derivation function and a set of physical layer parameters, a secret key for encrypting a unicast physical channel at a physical layer, wherein the secret key is a UE-specific secret key; and transmit, to a user equipment (UE), an encrypted transmission over the unicast physical channel based at least in part on the secret key. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein the one or more processors, to determine the secret key, are configured to determine the secret key based at least in part on the key derivation function, a long term key, a time value based at least in part on a key refresh interval and a current time, an identifier associated with the base station, and the set of physical layer parameters. ### Claim 13 (depends on 11) The apparatus of claim 11, wherein determining the secret key comprises determining the secret key based at least in part on the key derivation function, a broadcast root key, and the set of physical layer parameters, wherein the broadcast root key is based at least in part on the key derivation function, a long term key, and a time value based at least in part on a key refresh interval and a current time. ### Claim 14 (depends on 11) The apparatus of claim 11, wherein determining the secret key comprises determining the secret key based at least in part on the key derivation function, a radio access network (RAN) node specific key, and the set of physical layer parameters, wherein the RAN node specific key is based at least in part on the key derivation function, a broadcast root key, and an identifier of the base station received in a synchronization signal block. ### Claim 15 (depends on 11) The apparatus of claim 11, wherein the set of physical layer parameters include one or more of: a cell identifier, transmission configuration indicator state information indicated for receiving or transmitting the unicast physical channel, a scrambling identifier for generating a demodulation reference signal for the unicast physical channel, a zone identifier, positioning information, or an active bandwidth part (BWP) configuration that indicates a BWP index and a BWP bandwidth. ### Claim 16 (depends on 11) The apparatus of claim 11, wherein the set of physical layer parameters include transmission configuration indicator state information, and wherein the one or more processors are further configured to determine the secret key based at least in part on a resource identifier or a resource set identifier of a reference signal that functions as a source of a quasi co-location for the unicast physical channel, wherein the resource identifier or the resource set identifier includes a synchronization signal block index, a channel state information reference signal resource identifier, or a sounding reference signal resource identifier. ### Claim 17 (depends on 11) The apparatus of claim 11, wherein the set of physical layer parameters include transmission configuration indicator state information, and wherein the one or more processors are further configured to determine the secret key based at least in part on a quasi co-location (QCL) type, wherein the QCL type is associated with a key reference that is used as an input to the key derivation function. ### Claim 18 (depends on 11) The apparatus of claim 11, wherein the set of physical layer parameters is common for a plurality of unicast physical channels. ### Claim 19 (depends on 11) The apparatus of claim 11, wherein the set of physical layer parameters includes at least one parameter that is different from at least one other parameter between a plurality of unicast physical channels, wherein the set of physical layer parameters includes, for a physical uplink control channel, a control resource identifier, a control resource set identifier, and a timing advance command, and wherein the set of physical layer parameters includes, for a physical downlink control channel, a control channel monitoring configuration. ### Claim 20 (depends on 11) The apparatus of claim 11, wherein the one or more processors are further configured to: transmit, to the UE, an indication of the set of physical layer parameters. ### Claim 21 A method of wireless communication performed by a user equipment (UE), comprising: determining, based at least in part on a key derivation function and a set of physical layer parameters, a secret key for encrypting a unicast physical channel at a physical layer, wherein the secret key is a UE-specific secret key; and transmitting, to a base station, an encrypted transmission over the unicast physical channel based at least in part on the secret key. ### Claim 22 (depends on 21) The method of claim 21, wherein: determining the secret key comprises determining the secret key based at least in part on the key derivation function, a long term key, a time value based at least in part on a key refresh interval and a current time, an identifier associated with the base station, and the set of physical layer parameters; determining the secret key comprises determining the secret key based at least in part on the key derivation function, a broadcast root key, and the set of physical layer parameters, wherein the broadcast root key is based at least in part on the key derivation function, a long term key, and a time value based at least in part on a key refresh interval and a current time; or determining the secret key comprises determining the secret key based at least in part on the key derivation function, a radio access network (RAN) node specific key, and the set of physical layer parameters, wherein the RAN node specific key is based at least in part on the key derivation function, a broadcast root key, and an identifier of the base station received in a synchronization signal block. ### Claim 23 (depends on 21) The method of claim 21, wherein the set of physical layer parameters include one or more of: a cell identifier, transmission configuration indicator state information indicated for receiving or transmitting the unicast physical channel, a scrambling identifier for generating a demodulation reference signal for the unicast physical channel, a zone identifier, positioning information, or an active bandwidth part (BWP) configuration that indicates a BWP index and a BWP bandwidth. ### Claim 24 (depends on 21) The method of claim 21, wherein the set of physical layer parameters include transmission configuration indicator state information, and further comprising: determining the secret key based at least in part on a resource identifier or a resource set identifier of a reference signal that functions as a source of a quasi co-location (QCL) for the unicast physical channel, wherein the resource identifier or the resource set identifier includes a synchronization signal block index, a channel state information reference signal resource identifier, or a sounding reference signal resource identifier; or determining the secret key based at least in part on a QCL type, wherein the QCL type is associated with a key reference that is used as an input to the key derivation function. ### Claim 25 (depends on 21) The method of claim 21, wherein: the set of physical layer parameters is common for a plurality of unicast physical channels; or the set of physical layer parameters includes at least one parameter that is different from at least one other parameter between a plurality of unicast physical channels, wherein the set of physical layer parameters includes, for a physical uplink control channel, a control resource identifier, a control resource set identifier, and a timing advance command, and wherein the set of physical layer parameters includes, for a physical downlink control channel, a control channel monitoring configuration. ### Claim 26 A method of wireless communication performed by a base station, comprising: determining, based at least in part on a key derivation function and a set of physical layer parameters, a secret key for encrypting a unicast physical channel at a physical layer, wherein the secret key is a UE-specific secret key; and transmitting, to a user equipment (UE), an encrypted transmission over the unicast physical channel based at least in part on the secret key. ### Claim 27 (depends on 26) The method of claim 26, wherein: determining the secret key comprises determining the secret key based at least in part on the key derivation function, a long term key, a time value based at least in part on a key refresh interval and a current time, an identifier associated with the base station, and the set of physical layer parameters; determining the secret key comprises determining the secret key based at least in part on the key derivation function, a broadcast root key, and the set of physical layer parameters, wherein the broadcast root key is based at least in part on the key derivation function, a long term key, and a time value based at least in part on a key refresh interval and a current time; or determining the secret key comprises determining the secret key based at least in part on the key derivation function, a radio access network (RAN) node specific key, and the set of physical layer parameters, wherein the RAN node specific key is based at least in part on the key derivation function, a broadcast root key, and an identifier of the base station received in a synchronization signal block. ### Claim 28 (depends on 26) The method of claim 26, wherein the set of physical layer parameters include one or more of: a cell identifier, transmission configuration indicator state information indicated for receiving or transmitting the unicast physical channel, a scrambling identifier for generating a demodulation reference signal for the unicast physical channel, a zone identifier, positioning information, or an active bandwidth part (BWP) configuration that indicates a BWP index and a BWP bandwidth. ### Claim 29 (depends on 26) The method of claim 26, wherein the set of physical layer parameters include transmission configuration indicator state information, and further comprising: determining the secret key based at least in part on a resource identifier or a resource set identifier of a reference signal that functions as a source of a quasi co-location (QCL) for the unicast physical channel, wherein the resource identifier or the resource set identifier includes a synchronization signal block index, a channel state information reference signal resource identifier, or a sounding reference signal resource identifier; or determining the secret key based at least in part on a QCL type, wherein the QCL type is associated with a key reference that is used as an input to the key derivation function. ### Claim 30 (depends on 26) The method of claim 26, wherein: the set of physical layer parameters is common for a plurality of unicast physical channels; or the set of physical layer parameters includes at least one parameter that is different from at least one other parameter between a plurality of unicast physical channels, wherein the set of physical layer parameters includes, for a physical uplink control channel, a control resource identifier, a control resource set identifier, and a timing advance command, and wherein the set of physical layer parameters includes, for a physical downlink control channel, a control channel monitoring configuration.