Extended Packet Number Field in GCMP Nonce
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Solution Overview
Problem
Current wireless communication protocols, such as GCMP, face security challenges due to the limited number of invocations allowed for a given temporal key, which can lead to premature exhaustion and compromise security by reusing initialization vectors, necessitating frequent key changes and increased overhead.
Innovation Solution
The implementation of a 96-bit GCMP nonce with an extended packet number field allows for more than 232 MPDUs to be encrypted using a single temporal key without repeating packet numbers, leveraging existing CCMP architecture and increasing the message integrity code length to enhance security and reduce key change overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a standard packet number field is used in GCMP encryption, then the encryption process is simple and fast, but the temporal key is exhausted after 2^32 invocations requiring frequent key changes
Solution Approach 1:
The patent extends the packet number field from 32 bits to 48 bits, adding 16 additional bits to the nonce structure. This dimensional expansion in the packet number space allows 2^48 invocations per temporal key instead of 2^32, dramatically reducing key change frequency while maintaining the same encryption algorithm and overall nonce structure approach
2Reliability
If frequent temporal key changes are implemented, then security is maintained, but overhead increases and efficiency decreases
Solution Approach 1:
The patent changes the packet number field length parameter from 32 bits to 48 bits in the nonce structure. This parameter change allows each temporal key to be used for significantly more encryptions (2^48 vs 2^32), reducing the frequency of key changes needed to maintain security while improving overall encryption efficiency by eliminating repeated key management overhead
3Loss of substance
If the packet number field is extended to prevent exhaustion, then key change overhead is reduced, but the nonce size and processing complexity increase
Solution Approach 1:
The extended 48-bit packet number field is segmented into a 16-bit priority field and a 32-bit sequence number field. This segmentation allows the system to maintain compatibility with existing 802.11e QoS mechanisms while extending the packet number space, reducing key change overhead without significantly increasing processing complexity since the segmentation leverages existing protocol structures
Data Source
AI summary
A system including a nonce module and an encryption module. The nonce module is configured to generate a nonce for each packet of a plurality of packets to be encrypted using a first temporal key. Each nonce includes a packet number that is different than packet numbers associated with other nonces generated by the nonce module for the plurality of packets. The packet number is greater than N bits in length, where N is an integer greater than 40. The encryption module is configured to encrypt, without reusing a value of the packet number, more than 2(N−1) packets of the plurality of packets using (i) the first temporal key and (ii) the nonces corresponding to the more than 2(N−1) packets using Galois/Counter Mode encryption.