Sequence Number Protection in Authentication Protocols
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Solution Overview
Problem
Conventional authentication procedures, such as the AKA protocol, are susceptible to replay attacks that compromise the protection of sequence numbers (SQNs) due to the use of exclusive-or operations and a lack of randomness in their protection mechanisms.
Innovation Solution
Incorporating a message authentication code (MAC) into the calculation of the keystream to protect SQNs, ensuring that each SQN has a unique keystream, making it impossible to find the XOR between different SQNs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional authentication procedures use exclusive-or operations for protecting sequence numbers, then the protection mechanism is simple, but the security against replay attacks is compromised
Solution Approach 1:
The patent changes the parameters of the protection mechanism by incorporating a message authentication code (MAC) into the keystream calculation. Instead of using only exclusive-or operations, the MAC is integrated with the sequence number and other parameters to generate a protected value. This parameter change transforms the simple XOR-based protection into a more secure MAC-based protection while maintaining reasonable complexity.
Solution Approach 2:
The patent introduces a message authentication code (MAC) as an intermediary element in the protection mechanism. The MAC serves as a mediator between the sequence number and the keystream generation process. By computing MAC over the sequence number and other parameters, and then incorporating this MAC into the keystream calculation, the system achieves stronger security without requiring a complete redesign of the authentication protocol.
2Ease of operation
If conventional authentication procedures lack randomness in protection mechanisms, then the implementation is deterministic, but the uniqueness of keystream for each SQN is compromised
Solution Approach 1:
The patent applies preliminary action by pre-computing the message authentication code (MAC) over the sequence number and other relevant parameters before generating the keystream. This preliminary computation of MAC ensures that each sequence number is transformed into a unique protected value before being used in the authentication process, guaranteeing keystream uniqueness while maintaining deterministic implementation.
Solution Approach 2:
The patent changes the parameters involved in keystream generation by incorporating the MAC output as an additional parameter. Instead of directly using the sequence number, the system uses the MAC-computed value derived from the sequence number, which transforms the input parameters to the keystream function. This parameter transformation ensures that even identical sequence numbers produce different keystreams when combined with different MAC inputs, thereby ensuring uniqueness.
3Use of energy by moving object
If authentication protocols use simple XOR operations, then the computational overhead is low, but the protection against replay attacks is insufficient
Solution Approach 1:
The patent introduces a message authentication code (MAC) computation as an intermediary step between the sequence number and the authentication verification. The MAC is computed over the sequence number and other parameters, and this MAC value is then incorporated into the authentication process. This intermediary computation provides strong replay attack protection because an attacker cannot simply replay captured authentication messages without detecting the MAC verification, while the computational overhead remains manageable compared to more complex cryptographic protocols.
Data Source
AI summary
Techniques and apparatus for protecting sequence numbers used in authentication procedures are described. One technique includes receiving, from a network, an authentication request comprising at least a random challenge. After receipt of the authentication request, a synchronization parameter is generated based at least in part on a key shared by the network and the UE, the random challenge, and a first message authentication code (MAC). The synchronization parameter and the first MAC are transmitted to the network in response to the authentication request.