Smartcard Clock Unit for Time-Synchronized OTP Generation
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Solution Overview
Problem
Conventional mobile communication devices cannot generate time-synchronized one-time passwords (OTPs) when disconnected from a network, as they rely on external time signals for OTP generation.
Innovation Solution
Incorporating a smartcard with an internal clock unit and power source, allowing for independent time information generation and synchronization, even when the device is not connected to a network, and securing the clock unit within a tamper-resistant environment to prevent tampering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the mobile communication device relies on external time signals from the base station for OTP generation, then the time synchronization accuracy is improved, but the device cannot generate OTPs when disconnected from the network
Solution Approach 1:
The time-synchronization function is segmented between the external base station (for initial synchronization) and the internal clock unit in the smartcard (for continuous operation). This allows the device to achieve high accuracy when connected while maintaining operational capability when disconnected, as the internal clock unit takes over time provision during disconnection.
Solution Approach 2:
The internal clock unit is pre-synchronized with external time signals when the device is connected to the network. This preliminary synchronization enables the clock unit to provide accurate time information for OTP generation even when the device later becomes disconnected from the network.
2Reliability
If the clock unit is integrated into the smartcard with tamper-resistant design, then the security against tampering is improved, but the device complexity increases
Solution Approach 1:
The smartcard acts as an intermediary security module that houses the clock unit and secret key in a tamper-resistant environment. This separates the security-critical functions from the main device, providing enhanced protection while keeping the overall system architecture modular and manageable.
Solution Approach 2:
The clock unit is nested within the smartcard, which itself is inserted into the mobile communication device. This nested structure allows the clock unit to benefit from the tamper-resistant properties of the smartcard while maintaining a compact integrated design.
Data Source
Figure 1~2
AI summary
The invention relates to a mobile communication device comprising a terminal and a smartcard connected to the terminal and comprising a processing unit (202) adapted to generate a time-dependent password, wherein the smartcard includes a power source (204) and a clock unit (201), which can be supplied with power by the power source (204), and wherein the processing unit (202) is adapted to generate the time-dependent password based on a time signal from the clock unit (201). Furthermore, the Invention relates to a smartcard and a method for generating a time-dependent password.