Dual Channel SIM Card Data Storage via Cross-Interface Access
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Solution Overview
Problem
Existing SIM cards lack the ability to read data written using one interface back using another interface, limiting data accessibility and storage capacity, as they manage data separately through legacy ISO and high-speed interfaces.
Innovation Solution
Implementing a method where data is written via one interface and read back using another, utilizing both ISO 7816 and high-speed interfaces, such as MMC or USB, to store data in either EEPROM or flash memory based on file attributes, allowing data transfer between interfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data is stored separately in EEPROM and flash memory using independent routines for each interface, then data security and interface compatibility are maintained, but data accessibility and storage capacity are limited
Solution Approach 1:
The patent combines the legacy ISO interface and high-speed interface into a unified data access system where data written through either interface can be read back through either interface. This merging allows the SIM card to treat both interfaces as part of a single storage system, enabling cross-interface data access while maintaining the security and compatibility benefits of separate storage paths.
Solution Approach 2:
The patent implements universal data access by enabling both the ISO interface and high-speed interface to perform both write and read operations on the same data set. This multi-functionality allows the storage system to serve multiple purposes: maintaining legacy compatibility through ISO while enabling high-speed data transfer, all through a single unified storage backend that both interfaces can access.
2Reliability
If data is stored in EEPROM using legacy ISO interface, then data security is maintained, but storage capacity is insufficient
Solution Approach 1:
The patent nests the high-capacity flash memory storage within the security framework of the legacy SIM card system. The flash memory, which provides large storage capacity, is accessed through the high-speed interface but managed as part of the unified storage system that maintains ISO compatibility. This nesting allows the system to embed large-capacity storage within the secure legacy architecture without compromising security protocols.
3Adaptability or versatility
If separate routines are used for writing and reading data through different interfaces, then interface independence is maintained, but data transfer efficiency is reduced
Solution Approach 1:
The patent merges the independent write and read routines into a unified data access mechanism. Instead of requiring separate processing paths for writing through ISO interface and reading through high-speed interface, the system implements a common storage management layer that handles both operations efficiently, allowing data to flow freely between interfaces without redundant processing.
Data Source
AI summary
A SIM card comprising at least a first interface and a second interface different from the first interface is disclosed. In some embodiments, the SIM card is operative to receive data through the first interface, store the received data within the SIM card, and send back the stored data via the second interface. This enables a host operatively coupled with the SIM card to write data to the SIM card via the first interface and to read back the data via the second interface. Furthermore, a technique for extending the SIM EEPROM storage by keeping a portion of the file in flash is provided.