Cellular Authentication Concealed Identifier Generation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current cellular communication systems, particularly 5G systems, face challenges in preventing linkability attacks where attackers can generate valid subscription concealed identifiers using a legitimate subscriber's permanent identifier and public key, compromising authentication security.
Innovation Solution
The solution involves generating a concealed identifier based on a subscription identifier and a long-term derivative, which includes a replay attack protector, and using a one-way function to create a cryptographically secure message authentication code, making it difficult for attackers to generate valid identifiers without the legitimate subscriber's long-term key.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a concealed identifier is generated using only the subscription identifier and public key, then the identifier can be generated by anyone with public information, but this compromises authentication security and enables linkability attacks
Solution Approach 1:
The patent introduces a long-term derivative as an intermediary element that bridges the subscription long-term key and the concealed identifier generation. This derivative is computed using a key derivation function that incorporates the subscription long-term key and additional inputs (such as a replay attack protector and encryption scheme identifier), creating a secure intermediary that enables proper authentication while preventing linkability attacks.
Solution Approach 2:
The patent changes the parameter space for identifier generation by introducing the long-term derivative as a new critical parameter. Instead of generating identifiers from static public information alone, the system uses the derived key material that changes based on the subscription key and additional inputs, thereby transforming the generation process into a secure cryptographic operation that prevents unauthorized generation.
2Reliability
If the subscription long-term key is stored in the subscription module, then authentication can be performed securely, but the key management complexity increases
Solution Approach 1:
The patent extracts the critical security function from storing the raw subscription long-term key in the subscription module. Instead of storing the key itself, the system stores only the subscription identifier and derives the long-term derivative locally during authentication. This extraction of the key material from storage eliminates the need for secure key storage mechanisms while maintaining authentication security.
Solution Approach 2:
The patent performs preliminary key derivation by computing the long-term derivative using the subscription long-term key and additional inputs (replay attack protector, encryption scheme identifier) before the actual authentication occurs. This preliminary action prepares the derived key material in advance, allowing secure authentication without requiring the subscription module to store or manage the long-term key directly.
3Reliability
If a replay attack protector is added to prevent replay attacks, then security against replay attacks improves, but the identifier structure and processing complexity increase
Solution Approach 1:
The patent embeds the replay attack protector within the broader context of the key derivation process. The replay attack protector is used as an input to the key derivation function that computes the long-term derivative, which in turn is used to generate the concealed identifier and MAC tag. This nesting of the replay protection mechanism within the existing authentication flow integrates security functionality without significantly increasing structural complexity.
Data Source
Figure 1~3
Figure 2
Figure 4~6
AI summary
According to an example aspect of the present invention, there is provided a method, apparatus, and computer program for maintaining a subscription module, wherein the subscription module comprises a subscription identifier and a subscription long-term key; generating a long-term derivative from at least the subscription long-term key and a replay attack protector; and generating a concealed identifier based on at least the subscription identifier and the subscription long-term derivative.