Dynamic Derived Identity for Privacy in Communication Systems
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Solution Overview
Problem
In communication systems, user privacy is compromised due to linkability attacks, where a user's sessions can be linked across multiple applications or base stations, revealing private information, especially when using the same user identity repeatedly.
Innovation Solution
Generating a derived identity associated with a user based on a key and session variables, which is used to facilitate secure communications without revealing the actual user identity, utilizing a key server to manage and encrypt communications, and varying the identity or key with session-dependent variables to prevent tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a user exchanges the same user identity with an application over multiple sessions, then the application can recognize and service the user consistently, but the application can infer private information about the user by linking the user's sessions to each other
Solution Approach 1:
The patent applies dynamics by making the user identity dynamic rather than static. Instead of using the same identity across sessions, the system generates a new identity for each session based on the user's private key and session-specific parameters. This dynamic identity generation allows the application to service the user consistently through cryptographic verification while preventing linkage between sessions, as each session presents a unique identity that cannot be correlated with previous or future sessions.
Solution Approach 2:
The patent segments the user identity into multiple session-specific identities. Rather than using a single persistent identity, the system creates separate identities for each session that are cryptographically derived from the user's private key but cannot be reverse-engineered to reveal the private key or link to other sessions. This segmentation isolates each session's identity information, preventing aggregation and linkage attacks while maintaining user recognition through the underlying cryptographic key.
2Adaptability or versatility
If a user accesses several different applications using the same user identity, then the user can maintain a consistent identity across services, but a third party can ascertain which applications the user has accessed and when by passively eavesdropping
Solution Approach 1:
The system makes the user identity dynamic by generating a new identity for each application session based on the user's private key and session-specific parameters. This allows the user to maintain consistent access across applications through cryptographic verification while preventing third parties from tracking which applications the user accesses. Each session's unique identity breaks the correlation between user actions and observable identity exchanges.
Solution Approach 2:
The patent introduces cryptographic derivation as an intermediary layer between the user's private key and the presented identity. This intermediary process transforms the static private key into dynamic session-specific identities that serve as mediators: they allow the application to verify the user's authenticity while preventing direct observation of the link between the user and their actions. The intermediary cryptographic function masks the relationship between the user's private key and the presented identity.
3Loss of information
If derived identities are generated using session variables for each communication session, then user privacy is protected by preventing session linkage, but the system complexity increases due to key and identity management requirements
Solution Approach 1:
The patent applies self-service by enabling the user's device to autonomously generate derived identities using the user's private key and session-specific parameters. The device performs the cryptographic derivation locally without requiring external key management infrastructure or complex centralized systems. This self-service approach protects user privacy through distributed identity generation while minimizing system complexity by eliminating the need for complex external key management services.
Solution Approach 2:
The patent creates a universal identity generation mechanism that works across multiple applications and sessions using a single private key. The derived identity function is multi-functional, serving both authentication purposes (verifying user identity to applications) and privacy protection (preventing session linkage). This universal approach simplifies the system by using one cryptographic key for all sessions rather than requiring separate key management for each application or session.
Data Source
AI summary
Methods and apparatus for protecting user privacy in a shared key system. According to one aspect, a user generates a derived identity based on a key and a session variable, and sends the derived identity to an application. In one embodiment, a key server may be used to receive the derived identity from the application, and return a sub-key to the application to use for encrypting communications with the user.