802.11 Multi-Link Encryption Using Link-Independent Address Fields
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Solution Overview
Problem
In multi-link operations (MLO) compliant with the IEEE 802.11 standard, the immutable fields in frame headers cannot be changed after encryption, leading to decryption issues as the recipient lacks necessary link information, rendering the message undecryptable.
Innovation Solution
Setting certain address fields in the AAD to known values, such as all zeros, allows encryption to occur without knowledge of the specific link, enabling decryption by the intended recipient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If address fields in frame headers are set to link-specific values before encryption, then decryption can be performed correctly, but the system cannot adapt to dynamic link selection in multi-link operations
Solution Approach 1:
The patent segments the address fields into two categories: immutable fields (BSSID, transmitter address, receiver address) that remain unchanged and are used for encryption, and mutable fields (duration, identifier, sequence control) that can be modified after encryption. This segmentation allows the encryption process to use stable link-independent values while permitting link-specific modifications after encryption, resolving the contradiction between adaptability and decryption reliability.
Solution Approach 2:
The patent applies preliminary action by performing encryption before link selection and transmission. The address fields are set to predetermined values (such as BSSID for transmitter address and receiver address for receiver address) before encryption occurs, ensuring that the encryption process is link-independent. After encryption, the mutable fields can be updated with link-specific information, allowing the system to adapt to different links while maintaining decryption capability.
2Ease of operation
If address fields are modified after encryption to reflect link information, then the message can be routed correctly, but the recipient cannot decrypt the message due to missing link information
Solution Approach 1:
The patent segments the frame structure into immutable address fields used for encryption and mutable information fields that can be modified. The immutable fields (BSSID, transmitter address, receiver address) contain the necessary link-independent information for decryption, while the mutable fields (duration, identifier, sequence control) can be updated with link-specific routing information after encryption without affecting decryption capability.
Solution Approach 2:
The patent introduces an intermediary approach where the encryption process uses predetermined address values as intermediaries that bridge the gap between link-independent encryption requirements and link-specific transmission needs. These intermediary values (BSSID, receiver address) serve as stable references for both encryption and decryption while allowing flexible link selection.
3Reliability
If link-specific address values are used in encryption, then decryption works correctly, but the system lacks flexibility for multi-link operations
Solution Approach 1:
The patent applies universality by using link-independent address values (BSSID for transmitter address, receiver address for receiver address) that serve multiple functions: they enable correct encryption and decryption while also being applicable across multiple links. This universal approach allows the same encryption process to work regardless of which specific link is selected for transmission, providing both reliability and flexibility for multi-link operations.
Data Source
AI summary
Systems and methods are provided for encryption enhancement for a multi-link operation. Various subsets of addresses (or all addresses) associated with the frame are set to a determined known value, allowing encryption of the mac protocol data unit (MPDU) at a controller without knowledge of which particular link the frames will be sent. The multi-link devices (MLDs) used in the above communication may conduct communications in compliance with the IEEE 802.11be standard.