Split SIM Data Storage for Wireless Device Security
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Solution Overview
Problem
Current methods for securing subscriber identity module (SIM) data in wireless devices are inadequate, as they can be compromised by malicious access to physical interfaces or side channel attacks, exposing sensitive user data.
Innovation Solution
Encrypting select SIM data using a processor external to the secure element, dividing it into parts, and storing these parts in both the secure element and non-volatile memory, with cryptographic keys stored securely, ensuring that access to one part without the other or the key is insufficient for decryption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If SIM data is stored in unencrypted format on UICC for easy access during boot-up and registration, then ease of operation is improved, but security is worsened as malicious parties can access sensitive data by obtaining the SIM card
Solution Approach 1:
The patent divides encrypted SIM data into multiple parts, storing some parts in the secure element (UICC) and other parts in non-volatile memory outside the secure element. This segmentation ensures that even if the UICC is obtained by a malicious party, they cannot access the complete unencrypted SIM data without also obtaining the other parts and the cryptographic key.
Solution Approach 2:
The patent performs encryption of SIM data before storage, and further divides the encrypted data into multiple parts. This preliminary action of encrypting and segmenting the data ensures that the data is protected before any access attempts occur, resolving the security vulnerability of storing unencrypted data.
2Object-affected harmful factors
If SIM data is encrypted and divided into multiple parts stored in separate locations, then security is improved, but device complexity is worsened due to additional encryption/decryption operations and multiple storage locations
Solution Approach 1:
The patent implements automatic encryption and decryption processes that occur without user intervention. The system automatically encrypts SIM data before storage, divides it into parts, and handles the decryption process during normal operations. This self-service approach masks the underlying complexity from the user while maintaining security.
3Object-affected harmful factors
If cryptographic keys are stored externally to the secure element, then security is improved by preventing access without both parts and key, but reliability is worsened by introducing additional external storage dependencies
Solution Approach 1:
The patent merges the secure storage function (in the secure element) with external storage (non-volatile memory) and external key management. By combining these elements into a unified security architecture where all components must work together for successful data access, the system achieves both enhanced security and maintained reliability through coordinated operation of integrated components.
Data Source
AI summary
This application describes techniques for managing subscriber identity module (SIM) data for a wireless device, including secure storage and processing of SIM data. Select SIM data is encrypted using an encryption key by a processor external to a secure element, e.g., a universal integrated circuit card (UICC) or electronic UICC (eUICC), and at least a portion of the select SIM data is stored in the secure element. The select SIM data can be divided into multiple parts, where a first part of the encrypted SIM data is stored in the secure element, while a second part of the encrypted SIM data is stored external to the secure element, such as in a non-volatile memory (NVM) of the wireless device. The encryption key is stored in a secure NVM of the wireless device. The encrypted SIM data and the encryption key are required to decrypt and recover the SIM data.