Facebook Patent | Inline encryption of packet data

Patent: Inline encryption of packet data

Drawings: Click to check drawins

Publication Number: 20210149830

Publication Date: 20210520

Applicant: Facebook

Abstract

The disclosure describes wireless communication systems. The wireless communication system includes first memory, second memory, a direct memory access (DMA) controller, an encryption engine in-line between the DMA controller and the second memory, a first microprocessor, and a second microprocessor. The first microprocessor communicates with other systems that generate application data to be wirelessly transmitted. The application data to be wirelessly transmitted is stored in the second memory and programs the DMA controller to transfer packets of the application data to the first memory from the second memory. The encryption engine receives the packets of the application data from the DMA controller, encrypts the packets to generate encrypted application data packets, and outputs the encrypted application data packets for storage to the first memory.

Claims

  1. A wireless communication system comprising: first memory; second memory; a first microprocessor configured to communicate with other systems that generate application data to be wirelessly transmitted, wherein the application data to be wirelessly transmitted is stored in the second memory; a direct memory access (DMA) controller; an encryption engine in-line between the DMA controller and the second memory, wherein the first microprocessor is configured to program the DMA controller to transfer packets of the application data to the first memory from the second memory, wherein the encryption engine is configured to receive the packets of the application data from the DMA controller, encrypt the packets to generate encrypted application data packets, and output the encrypted application data packets for storage to the first memory.

  2. The wireless communication system of claim 1, wherein the first microprocessor is configured to generate a transmission header for each of the packets of application data, and wherein the wireless communication system further comprises a second microprocessor configured to drive a wireless data bus interface to transmit, via a wireless transceiver, transmission packets each comprising one of the encrypted application data packets and a corresponding one of the transmission headers.

  3. The wireless communication system of claim 1, wherein the first microcontroller is further configured to: determine a number of transmission packets to create based on a size of the application data stored in the second memory; generate respective partially filled transmission headers for each of the transmission packets; and store the transmission headers to the first memory.

  4. The wireless communication system of claim 3, wherein the microcontroller is further configured to generate and store a header table in the first memory, the header table to store a list of addresses that specify locations of the transmission headers in the first memory.

  5. The wireless communication system of claim 4, wherein the microcontroller is configured to program the DMA controller with a descriptor table, the descriptor table specifying (a) a first location in the first memory storing the header table, (b) second locations in the second memory storing the packets of the application data, and (c) a third location in the first memory to store the transmission packets.

  6. The wireless communication system of claim 3, wherein the DMA controller is configured to retrieve the partially filled transmission headers from the first memory along with the corresponding packets of the application data from the second memory, and wherein the encryption engine is configured to, for each partially filled transmission header and corresponding portion of the application data, complete the partially filled transmission header with an encryption vector and encrypt the corresponding portion of the application data to create transmission packets to store in the first memory.

  7. The wireless communication system of claim 6, wherein the DMA controller is configured to store the transmission packets in a transmission buffer in the first memory to be transmitted by a wireless transceiver.

  8. A wireless communication system comprising: first memory; second memory; a first microprocessor; a direct memory access (DMA) controller; an encryption engine in-line between the DMA controller and the first memory; wherein the first microprocessor is configured to program the DMA controller with a first address in the first memory identifying a location of transmission packets and a second address identifying a second location in the second memory; wherein the DMA controller is configured to pull the transmission packets through the encryption engine to generate application data packets and store the application data packets at the second location of the second memory; and wherein the encryption engine is configured to decrypt encrypted application data packets within the transmission packets.

  9. The wireless communication system of claim 8, comprising a second microprocessor, wherein the first microprocessor is configured to program the DMA controller with the location in the first memory of the transmission packets in response to receiving a signal from the second microprocessor indicative that transmission packets have been received by a wireless transceiver and are stored in the first memory.

  10. The wireless communication system of claim 8, comprising: a second microprocessor; and a wireless data bus interface communicatively coupled to a wireless transceiver, wherein the wireless data bus interface is configured to, in response to receiving transmission packets, store the transmission packets at a location in the first memory; and wherein the second microprocessor is configured to write the locations in first memory of the transmission packets to a register accessible by the first microprocessor.

  11. The wireless communication system of claim 8, wherein the encryption engine is configured to, for each one of the transmission packets, determine a validity of the transmission packet based on a transmission header within the transmission packet.

  12. The wireless communication system of claim 11, wherein in response to determining that one of the transmission packets is not valid, the encryption engine is configured to send a signal to the first microcontroller and cease processing transmission packets.

  13. A method comprising: pulling from first locations in a first memory, by a direct access memory (DMA) controller, transmission headers to an encryption engine in-line between the DMA controller and a second memory; pulling from second locations in the second memory, by the DMA controller, packets of application data to the encryption engine; completing, by the encryption engine, an encryption block within each of the transmission headers; encrypting, by the encryption engine, the packets of the application data; and storing in third locations in first memory, by the DMA controller, transmission packets each comprising one of the completed transmission headers and the corresponding encrypted packet of the application data.

  14. The method of claim 13, further comprising moving, by a wireless microcontroller, the transmission packets from the third locations in the first memory to a transmission buffer to be transmitted by a wireless receiver.

  15. The method of claim 13, further comprising: determining, by an isolation microprocessor, a number of the application data packets to create based on application data stored in the second locations in the second memory; generating corresponding ones of the transmission headers for each of the application data packets; and storing the transmission headers to the first locations in the first memory.

  16. The method of claim 15, further comprising generating and storing, by the isolation microprocessor, a header table in a fourth location in the first memory, the header table to list address of the first locations in the first memory.

  17. The method of claim 16, further comprising providing, by the isolation microprocessor, the header table and the second locations in second memory to the DMA controller.

  18. The method of claim 13, wherein completing, the encryption block within each of the transmission headers further comprises generating, by the encryption engine, an encryption vector based on the corresponding application data packet to be encrypted.

  19. The method of claim 18, wherein the encryption vector is configured to facilitate, by a receiving device, determining whether the corresponding portion of the application data to be encrypted has been tampered with.

Description

[0001] This application claims the benefit of U.S. Provisional Application No. 63/004,315 filed Apr. 2, 2020, U.S. Provisional Application No. 63/004,170, filed Apr. 2, 2020, U.S. Provisional Application No. 62/940,780 filed Nov. 26, 2019, and U.S. Provisional Application No. 62/935,964, filed Nov. 15, 2019, the entire content of each of which are herein incorporated by reference.

TECHNICAL FIELD

[0002] In general, this disclosure relates to wireless communication systems.

BACKGROUND

[0003] Devices communicate wirelessly using one or more wireless protocols. Wireless protocols include the WiFi standards (IEEE 802.11 and subsequent amendments, e.g., 802.11a, 802.11b, 802.11g, 802.11ad, and so forth), Bluetooth, LorRa, Zigbee, and others. Wireless communications involve transmitting packetized data over the air from a source device to a destination device using a wireless physical layer link.

SUMMARY

[0004] As described below, a wireless communication system includes multiple microcontrollers to manage the transfer of data between shared memory and one or more wireless transceivers. The wireless communication system includes a wireless microcontroller (WMCU) that manages drivers for the wireless transceivers and orchestrates data movement between the I/O ports associated with the wireless transceivers and physical memory that includes, for example, a transmission buffer and a reception buffer (sometime referred to as “wireless memory” or “WMEM”). The wireless communication system includes an isolation microcontroller (IMCU) that communicates with other memory management components of the wireless communication system to, for example, prepare packets for transmission by the wireless transceivers. The shared memory is memory that is accessible to multiple subsystems (e.g., different system-on-a-chip (SoC) integrated circuits, etc.) of a device via a memory data bus (e.g., a network-on-a-chip (NoC) data bus). The shared memory may be physically isolated, e.g., a different memory device, from the wireless memory. While the isolation microcontroller has access to the shared memory and the wireless memory, the isolation microcontroller controls access to the shared memory such that the wireless microcontroller does not have direct access to the shared memory.

[0005] A subsystem that has application data to be transmitted over a wireless transceiver places the data to be transferred and a header (collectively referred to as “application data”) into the shared memory. The subsystem then provides the location of the application data to the isolation microcontroller. The isolation microcontroller creates packets and corresponding packet headers from the application data, and the isolation microcontroller orchestrates data movement between the shared memory and the wireless memory. In this way, access to shared memory by a microcontroller or other processing circuitry that is processing received wireless packets is mediated by the isolation microcontroller.

[0006] In some examples, the wireless microcontroller executes the full set of one or more drivers for the wireless transceivers, but the isolation microcontroller may execute a more limited code to orchestrate data movement and manage packetization. In addition, the wireless microcontroller may only have access to the wireless memory. Because malformed packets may be used to exploit vulnerabilities of the drivers executed by the wireless microcontroller, bifurcating the data movement and wireless transceiver control between the isolation microcontroller and the wireless microcontroller may improve the security of the wireless communication system by reducing, and in some cases eliminating, vulnerabilities of the engines and the isolation microcontroller to malformed packets received by the wireless transceivers and stored to wireless memory.

[0007] In some examples, the wireless communication system includes an inline encryption/decryption engine to encrypt and decrypt packets on a data path, managed by the isolation microcontroller, between the shared memory and the wireless transceivers. For example, the isolation microcontroller creates encryption headers in the wireless memory for packets to be formed from application data generated by other engines of a device that includes the wireless communication system. The isolation microcontroller may program a direct memory access (DMA) controller (e.g., via control and status register writes, etc.) to direct the packets from shared memory along with corresponding packet headers from wireless memory to the encryption/decryption engine. The encryption/decryption engine generates encrypted packets that the programmed DMA controller then writes to wireless memory. That is, the isolation microcontroller communicates with subsystems that generate application data for wireless transmission, creates headers and packets from the application data in the shared memory, and orchestrates data movement between the shared memory and the wireless memory using the DMA controller. The isolation microcontroller also manages the data path for encrypted packets received by the wireless communication system to ensure inline decryption by the encryption/decryption engine. The isolation microcontroller then signals the wireless microcontroller when encrypted packets are ready to be transmitted.

[0008] The wireless microcontroller, which executes the drivers for the wireless transceiver, signals the isolation microcontroller indicating new received, encrypted packets. In response, the isolation microcontroller may program the DMA controller to direct received, encrypted packets from the wireless memory to the encryption/decryption engine, which decrypts the packets with headers from the encrypted packets, and the programmed DMA controller writes the packet data to application payload destination memory allocated in the shared memory. In this way, the application payload is stored to shared memory of a destination device in the same image as the application payload was in the shared memory of the sender device.

[0009] In some cases, the encryption/decryption engine for the wireless communication system increments an encryption packet counter for every packet encrypted by the engine. The packet counter value is then transmitted in the header along with the packet. On the receiver side, the counterpart encryption/decryption engine reads the packet counter from the header and initializes local decryption using a local copy of the nonce and the received packet counter. In this way, each packet can be decrypted and validated individually, and the loss of a packet has no impact on future or past packets.

[0010] In one example, a wireless communication system includes first memory, second memory, a direct memory access (DMA) controller, an encryption engine in-line between the DMA controller and the second memory, a first microprocessor, and a second microprocessor. The first microprocessor communicates with other systems that generate application data to be wirelessly transmitted. The application data to be wirelessly transmitted is stored in the second memory and programs the DMA controller to transfer packets of the application data to the first memory from the second memory. The encryption engine receives the packets of the application data from the DMA controller, encrypts the packets to generate encrypted application data packets, and outputs the encrypted application data packets for storage to the first memory.

[0011] In another example, a wireless communication system includes first memory, second memory, a first microprocessor, a direct memory access (DMA) controller, and an encryption engine in-line between the DMA controller and the first memory. The first microprocessor programs the DMA controller with a first address in the first memory identifying a location of transmission packets and a second address identifying a second location in the second memory. The DMA controller pulls the transmission packets through the encryption engine to generate application data packets and stores the application data packets at the second location of the second memory. The encryption engine decrypts encrypted application data packets within the transmission packets.

[0012] In another example, a method includes pulling from first locations in a first memory, by a direct access memory (DMA) controller, transmission headers to an encryption engine in-line between the DMA controller and a second memory. The method also includes pulling from second locations in the second memory, by the DMA controller, packets of application data to the encryption engine. Additionally, the method includes completing, by the encryption engine, an encryption block within each of the transmission headers. The method includes encrypting, by the encryption engine, the packets of the application data. Furthermore, the method includes storing in third locations in first memory, by the DMA controller, transmission packets each comprising one of the completed transmission headers and the corresponding encrypted packet of the application data.

[0013] The details of one or more examples of the techniques of this disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

[0014] FIG. 1A is an illustration depicting an example multi-device artificial reality system that implements a wireless communication system providing improved security and data movement for wireless communication, in accordance with aspects of this disclosure.

[0015] FIG. 1B is an illustration depicting another example multi-device artificial reality system that implements a wireless communication system providing improved security and data movement for wireless communication, in accordance with aspects of this disclosure.

[0016] FIG. 2 is an illustration depicting an example HMD configured to provide improved security and data movement for wireless communication, in accordance with the techniques of the disclosure.

[0017] FIG. 3 is a block diagram illustrating an example implementation of a distributed architecture for a multi-device artificial reality system in which one or more devices are implemented using one or more system on a chip (SoC) integrated circuits within each device and having wireless communication systems according to techniques of this disclosure.

[0018] FIG. 4 is a block diagram illustrating a wireless communication system, in accordance with the techniques of the disclosure.

[0019] FIGS. 5A-5E are block diagrams illustrating example management of application data by an isolation microcontroller to transmit the application data via a wireless transceiver, in accordance with the techniques described in this disclosure.

[0020] FIG. 6 is a block diagram illustrating an example of data structures and devices for forming wireless packets, in accordance with the techniques described in this disclosure.

[0021] FIG. 7 is a flowchart of an example method to transmit application data stored in shared memory via a wireless transceiver, in accordance with the techniques described in this disclosure.

[0022] FIG. 8 is a flowchart of an example method to perform inline encryption of application data to be transmitted via a wireless transceiver, in accordance with the techniques described in this disclosure.

[0023] FIG. 9 is a flowchart of an example method to stored application data that is received via a wireless transceiver in shared memory, in accordance with the techniques described in this disclosure.

[0024] FIG. 10 is a flowchart of an example method to perform inline decryption of application data received via a wireless transceiver, in accordance with the techniques described in this disclosure.

[0025] Like reference characters denote like elements throughout the text and figures.

DETAILED DESCRIPTION

[0026] Multi-device systems sometimes incorporate content protection or digital rights management technology, such as data encryption and decryption, as part of in-system, inter-device communications. A source device that originates an encrypted communication within the system may implement digital data encryption according to various standardized encryption mechanisms. A destination device that receives the encrypted communication for processing beyond simple relaying performs generally reciprocal or “inverse” steps with respect to the encryption mechanisms, in accordance with the inverse steps specified in the corresponding standard according to which the data was encrypted.

[0027] Encrypted inter-device communications are often performed in a packetized manner. The packetized communications are packaged as discrete data units (or “packets”), with each packet conforming to a format/structure. Packets of an inter-device encrypted data flow are referred to herein as “crypto packets.” Each crypto packet conforms to a format in which an encrypted payload is encapsulated within an “encryption header.” Various non-limiting examples of this disclosure are described with respect to peer-to-peer (P2P) unicast data flows between two devices of multi-device artificial reality systems.

[0028] Artificial reality systems are becoming increasingly ubiquitous with applications in many fields such as computer gaming, health and safety, industrial fields, and education. As a few examples, artificial reality systems are being incorporated into mobile devices, gaming consoles, personal computers, movie theaters, and theme parks. In general, artificial reality is a form of reality that has been adjusted in some manner before presentation to a user, and may include one or more of virtual reality (VR), augmented reality (AR), mixed reality (MR), hybrid reality, or some combination and/or derivative thereof.

[0029] Typical artificial reality systems include one or more devices for rendering and displaying content to users. As one example, a multi-device artificial reality system of this disclosure may include a head-mounted device (HMD) worn by a user and configured to output artificial reality content to the user, and a peripheral device that operates as a co-processing device when paired with the HMD. The artificial reality content may include completely generated content or generated content combined with captured content (e.g., real-world video and/or real-world images). The peripheral device and the HMD may each include one or more SoC integrated circuits (referred to herein simply as “SoCs”) that are collectively configured to provide an artificial reality application execution environment.

[0030] Because the HMD and peripheral device communicate secure data (e.g., authentication data) with each other, the respective SoCs of the HMD and the peripheral device send data to one another in the form of crypto packets. To further enhance security when sending the crypto packets, the HMD may include a wireless communication system that may bifurcate the data movement and wireless transceiver control between an isolation microcontroller and a wireless microcontroller, which may improve the security of the wireless communication system by reducing, and in some cases eliminating, vulnerabilities of the engines and the isolation microcontroller to malformed packets received by the wireless transceivers and stored to wireless memory.

[0031] FIG. 1A is an illustration depicting a multi-device artificial reality system 100, components of which are configured to provide improved security and data movement for wireless communication. As further described below, an HMD 102 may include a wireless communication system having multiple microcontrollers to manage the transfer of data between shared memory that stores application data to be wirelessly transmitted and one or more wireless transceivers that stores packets headers, descriptors, and encrypted payloads for wireless receive and transmission operations.

[0032] Multi-device artificial reality system 100 includes head-mounted device (HMD) 102 and peripheral device 104. As shown, HMD 102 is typically worn by user 106, and includes an electronic display and optical assembly for presenting artificial reality content 108 to user 106. In addition, HMD 102 includes one or more sensors (e.g., accelerometers) for tracking motion of HMD 102. HMD 102 may include one or more image capture devices 110, e.g., cameras, line scanners, fundal photography hardware, or the like. Image capture devices 110 may be configured for capturing image data of the surrounding physical environment. In some examples, image capture devices 110 include inward-facing camera hardware and/or scanning hardware configured to capture facial images, retina scans, iris scans, etc. of user 106 for user authentication and for other purposes. HMD 102 is shown in this example as being in communication with (e.g., in wireless communication with or tethered to) peripheral device 104. Peripheral device 104 represents a co-processing device in communication with HMD 102. HMD 102 and/or peripheral device 104 may execute an artificial reality application to construct artificial reality content 108 for display to user 106. For example, HMD 102 and/or peripheral device 104 may construct the artificial reality content based on tracking pose information and computing pose information for a frame of reference, typically a viewing perspective of HMD 102.

[0033] As shown in FIG. 1A, one or more devices of multi-device artificial reality system 100 may be connected to a computing network, such as network 112. Network 112 may incorporate a wired network and/or wireless network, such as a local area network (LAN), a wide area network (WAN), a Wi-Fi.TM. based network or 5G network, an Ethernet.RTM. network, a mesh network, a short-range wireless (e.g., Bluetooth.RTM.) communication medium, and/or various other computer interconnectivity infrastructures and standards. Network 112 may support various levels of network access, such as to public networks (e.g., the Internet), to private networks (e.g., as may be implemented by educational institutions, enterprises, governmental agencies, etc.), or private networks implemented using the infrastructure of a public network (e.g., a virtual private network or “VPN” that is tunneled over the Internet).

[0034] FIG. 1A also illustrates various optional devices that may be included in multi-device artificial reality system 100 or coupled to multi-device artificial reality system 100 via network 112. The optional nature of these devices is shown in FIG. 1A by way of dashed-line borders. One example of an optional device shown in FIG. 1A is console 114. In implementations that include console 114, console 114 may communicate with peripheral device 104 (and thereby, indirectly with HMD 102) to process artificial reality content that HMD 102 outputs to user 106. Another example of optional hardware shown in FIG. 1A is represented by external sensors 116. Multi-device artificial reality system 100 may use external sensors 116 and/or external camera hardware to capture three-dimensional (3D) information within the real-world, physical environment at which user 8 is positioned.

[0035] In general, multi-device artificial reality system 100 uses information captured from a real-world, 3D physical environment to render artificial reality content 108 for display to user 106. In the example of FIG. 1A, a user 106 views the artificial reality content 108 constructed and rendered by an artificial reality application executing on the combination of HMD 102 and peripheral device 104. In some examples, artificial reality content 108 may comprise a combination of real-world imagery (e.g., peripheral device 104 in the form of peripheral device representation 104’, representations of walls at the physical environment at which user 106 is presently positioned, a representation of the hand with which user 106 holds peripheral device 104, etc.) overlaid with virtual objects (e.g., virtual content items 118A and 118B, virtual user interface 120, etc.) to produce an augmented reality experience or a mixed reality experience displayed to user 106 via display hardware of HMD 102.

[0036] In some examples, virtual content items 118A and 118B (collectively, virtual content items 118) may be mapped to a particular position within artificial reality content 108. As examples, virtual content items 118 may be pinned, locked, or placed to/at certain position(s) within artificial reality content 108. A position for a virtual content item may be fixed, as relative to one of the walls of the real-world imagery reproduced in artificial reality content 108, or to the earth, as examples. A position for a virtual content item may be variable, as relative to peripheral device representation 104’ or to the tracked gaze or field of view (FoV) of user 106, as non-limiting examples. In some examples, the particular position of a virtual content item within artificial reality content 108 is associated with a position within the real-world, physical environment (e.g., on a surface of a physical object) at which user 106 is positioned presently.

[0037] In this example, peripheral device 104 is a physical, real-world device having a surface on which the artificial reality application executing on computing platforms of multi-device artificial reality system 100 overlays virtual user interface 120. Peripheral device 104 may include one or more presence-sensitive surfaces for detecting user inputs by detecting a presence of one or more objects (e.g., fingers, stylus) touching or hovering over locations of the presence-sensitive surface. In some examples, peripheral device 104 may include one or more output devices, such as a display integrated into the presence-sensitive surface to form an input/output (I/O) component of peripheral device 104.

[0038] In some examples, peripheral device 104 may have the form factor of various portable devices, such as a smartphone, a tablet computer, personal digital assistant (PDA), or other handheld device. In other examples, peripheral device 104 may have the form factor of various wearable devices, such as a so-called “smartwatch,” “smart ring,” or other wearable device. In some examples, peripheral device 104 may be part of a kiosk or other stationary or mobile system. While described above as integrating display hardware, peripheral device 6 need not include display hardware in all implementations.

[0039] In the example artificial reality experience shown in FIG. 1A, virtual content items 118 are mapped to positions on a visual representation of a wall of the real-world physical environment at which user 106 is positioned. The example in FIG. 1A also shows that virtual content items 118 partially appear on the visual representation of the wall only within artificial reality content 108, illustrating that virtual content items 118 do not represent any items that exist in the real-world, physical environment at which user 106 is positioned. Virtual user interface 120 is mapped to a surface of peripheral device 104 as represented in peripheral device representation 104’. Multi-device artificial reality system 100 renders virtual user interface 120 for display via HMD 102 as part of artificial reality content 108, at a user interface position that is locked relative to the position of a particular surface of peripheral device 104.

[0040] FIG. 1A shows that virtual user interface 120 appears overlaid on peripheral device representation 104’ (and therefore, only within artificial reality content 108), illustrating that the virtual content represented in virtual user interface 120 does not exist in the real-world, physical environment at which user 8 is positioned. Multi-device artificial reality system 100 may render one or more virtual content items in response to a determination that at least a portion of the location of virtual content items is in the FoV of user 106. For example, multi-device artificial reality system 100 may render virtual user interface 120 on peripheral device 104 only if peripheral device 104 is within the FoV of user 106.

[0041] Various devices of multi-device artificial reality system 100 may operate in conjunction in the artificial reality environment, such that each device may be a separate physical electronic device and/or separate integrated circuits within one or more physical devices. In this example, peripheral device 104 is operationally paired with HMD 102 to jointly operate to provide an artificial reality experience. For example, peripheral device 104 and HMD 102 may communicate with each other as co-processing devices. As one example, when a user performs a user interface-triggering gesture in the virtual environment at a location that corresponds to one of the virtual user interface elements of virtual user interface 120 overlaid on peripheral device representation 104’, multi-device artificial reality system 100 detects the user interface and performs an action that is rendered and displayed via HMD 102.

[0042] Each of peripheral device 104 and HMD 102 may include one or more SoC integrated circuits configured to support aspects of the artificial reality application described above, such as SoCs operating as co-application processors, encryption engines, decryption engines, sensor aggregators, display controllers, etc. Although each of peripheral device 104 and HMD 102 may include multiple SoCs, FIG. 1A only illustrates HMD SoC 122 of HMD 102 and peripheral SoC 124 of peripheral device 104, for ease of illustration and discussion. To preserve security and digital rights, HMD SoC 122 and peripheral SoC 124 are configured to communicate with one another using encrypted data streams, such as by sending crypto packet flows over a wireless link formed using respective peripheral component interface (PCI) express (PCIe) buses of HMD SoC 122 of HMD 102 and peripheral SoC 124. As just one example, HMD SoC 122 may encrypt facial images, retina scans, iris scans, etc. of user 106 (e.g., as captured by inward-facing camera hardware and/or fundal photography hardware of image capture devices 110), and send the encrypted data to peripheral SoC 124 for authentication purposes and optionally, for other purposes as well. In this example, peripheral SoC 124 may decrypt the encrypted data received from HMD SoC 122, and process the decrypted data using facial recognition technology, retinal blood vessel pattern recognition technology, etc. to grant/deny biometric authentication to user 106.

[0043] HMD SoC 122 and peripheral SoC 124 are described herein as performing encryption and decryption operations that comply with the standardized encryption and decryption mechanisms described in the advanced encryption standard (AES) established by the United States National Institute of Standards and Technology (NIST) as a non-limiting example. It will be appreciated that HMD SoC 122 and peripheral SoC 124 may, in other examples, implement the traffic constraint-based enhancements of this disclosure while complying with other cipher standards, such as SM4 (formerly SMS4, a block cipher standard set forth in the Chinese National Standard for Wireless LAN WAPI), Camellia (developed by Mitsubishi Electric and NTT Corporation of Japan), etc.

[0044] As described herein, HMD 102 may include a wireless communication system that improves the performance of encryption and decryption operations when sending or receiving encrypted packets from HMD SoC 122 to peripheral SoC 124.

[0045] In this example, each of HMD SoC 122 and peripheral SoC 124 includes multiple subsystems, with each subsystem being dedicated to supporting certain functionalities, such as audio processing for the artificial reality experience, moving picture processing for the artificial reality experience, security information for user 106 or others, etc. Additionally, HMD SoC 122 and peripheral SoC 124 implements a shared memory (SMEM) that stores data for all of the respective subsystems of that particular SoC. The various subsystems of HMD SoC 122 are configured to be mutually distrusting, and the various subsystems of peripheral SoC 124 are configured to be mutually distrusting, with respect to SMEM access. As such, each of HMD SoC 122 and peripheral SoC 124 are configured to limit access to discrete address spaces of their respective SMEM units to a specific, single subsystem.

[0046] In this example, HMD 102 may include a wireless communication system that comprises a first microcontroller (the “wireless microcontroller”) that manages drivers for the wireless transceivers of HMD 102 and orchestrates data movement between the I/O ports associated with the wireless transceivers and first physical memory (the “wireless memory”). The wireless memory may store packets headers, descriptors, and encrypted payloads for wireless receive and transmission operations. Peripheral device 104 may include a similar wireless communication system. The wireless communication systems of HMD 102 and peripheral device 104 facilitate wireless communication between HMD 102 and peripheral device 104. More particularly, HMD SoC 122 may include the wireless communication system of HMD 102 and peripheral SoC 124 may include the wireless communication system of peripheral device 104.

[0047] In some examples, the wireless communication system includes a second microcontroller (the “isolation microcontroller”, not shown in FIG. 1A) that communicates with other engines of the wireless communication system that generate application data to be wirelessly transmitted, which the other engines store to shared memory. Shared memory may be physically isolated, e.g., a different memory device, from the wireless memory. The isolation microcontroller creates packets and corresponding packet headers from the application data, and the isolation microcontroller orchestrates data movement between the shared memory and the wireless memory. In this way, access to shared memory by a microcontroller or other processing circuitry that is processing received wireless packets is mediated by the isolation microcontroller.

[0048] In some cases, the wireless microcontroller executes the full set of one or more drivers for the wireless transceivers, but the isolation microcontroller may execute a more limited code to orchestrate data movement and manage packetization. In addition, only the wireless microcontroller may have access to the wireless memory. Because malformed packets may be used to exploit vulnerabilities of the drivers executed by the wireless microcontroller, bifurcating the data movement and wireless transceiver control between the isolation microcontroller and the wireless microcontroller may improve the security of the wireless communication system by reducing, and in some cases eliminating, vulnerabilities of the engines and the isolation microcontroller to malformed packets received by the wireless transceivers and stored to wireless memory.

[0049] In some cases, the wireless communication system includes an inline encryption/decryption engine (not shown in FIG. 1A) to encrypt and decrypt packets on a data path, managed by the isolation microcontroller, between the shared memory and the wireless transceivers. For example, the isolation microcontroller creates encryption headers in the wireless memory for packets to be formed from application data generated by other engines of a device that includes the wireless communication system. The isolation microcontroller may program a direct memory access (DMA) controller to direct the packets from shared memory along with corresponding packet headers from wireless memory to the encryption/decryption engine, which generates encrypted packets that the programmed DMA controller writes to wireless memory. That is, the isolation microcontroller communicates with internal engines that generate application data for wireless transmission, creates headers and packets from the application data in the shared memory, and orchestrates data movement between the shared memory and the wireless memory using the DMA controller. The isolation microcontroller also manages the data path for encrypted packets received by the wireless communication system to ensure inline decryption by the encryption/decryption engine. The wireless microcontroller, which executes the drivers for the wireless transceiver, signals the isolation microcontroller indicating new received, encrypted packets. In response, the isolation microcontroller may program the DMA controller to direct received, encrypted packets from the wireless memory to the encryption/decryption engine, which decrypts the packets with headers from the encrypted packets, and the programmed DMA controller writes the packet data to application payload destination memory allocated in the shared memory. In this way, the application payload is stored to shared memory of a destination device in the same image as the application payload was in the shared memory of the sender device.

[0050] In some cases, the encryption/decryption engine for the wireless communication system increments an encryption packet counter for every packet encrypted by the engine. The packet counter value is then transmitted in the header along with the packet. On the receiver side, the counterpart encryption/decryption engine reads the packet counter from the header and initializes local decryption using a local copy of the nonce and the received packet counter. In this way, each packet can be decrypted individually, and a loss of a packet has no impact on future or past packets.

[0051] FIG. 1B is an illustration depicting another example multi-device artificial reality system 20 that includes a wireless communication system providing improved security and data movement for wireless communication, in accordance with the techniques described in this disclosure. Similar to multi-device artificial reality system 10 of FIG. 1A, HMD SoC 2 may include a wireless communication system having multiple microcontrollers to manage the transfer of data between shared memory that stores application data to be wirelessly transmitted and one or more wireless transceivers that stores packets headers, descriptors, and encrypted payloads for wireless receive and transmission operations.

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