Memory Device Time Stamp Update Policy for DRM Validation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Memory devices, such as TrustedFlash™, face challenges in accurately determining time for digital rights management (DRM) operations due to security concerns and the potential unavailability of network connectivity, making it unreliable to trust host devices for time information, and battery-backed clocks add cost without ensuring continuous time tracking.
Innovation Solution
The memory device implements a method to determine if a new time stamp is needed based on a time stamp update policy (TUP) associated with DRM licenses, obtaining a new time stamp when required, and using a time estimate generated from active time measurement to validate licenses, ensuring accuracy without continuous time tracking or relying on host device clocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the memory device uses a battery-backed clock to continuously track time, then time accuracy is improved, but device cost increases
Solution Approach 1:
The patent extracts the continuous time-tracking function from the memory device by relying on the host device's clock instead of implementing a battery-backed clock within the memory device itself. This removes the costly hardware component while maintaining time accuracy through the host's time source.
Solution Approach 2:
The host device acts as an intermediary, providing time information to the memory device. Instead of the memory device having its own time source, it uses the host device's clock through communication protocols, eliminating the need for expensive internal time-keeping hardware.
2Measurement precision
If the memory device measures active time continuously, then time estimate accuracy is improved, but power consumption increases
Solution Approach 1:
Instead of continuously measuring active time, the system uses periodic time stamps provided by the host device. The memory device receives time stamps at intervals during active periods and uses these periodic updates to maintain accurate time estimates without requiring continuous measurement operations.
Solution Approach 2:
The host device performs time tracking and preparation of time stamp data before the memory device needs it. By having the host device maintain the time source and prepare time stamps in advance, the memory device can obtain accurate time information without performing continuous measurements that would consume power.
3Device complexity
If the memory device relies on host device time, then device complexity is reduced, but time reliability deteriorates due to security concerns
Solution Approach 1:
The system dynamically adjusts its time source selection based on operational context. The memory device can switch between using the host device's time source and its own measured active time depending on security requirements, operational mode, and availability of trusted time stamps, making the time source flexible rather than fixed.
Solution Approach 2:
The system changes the trust parameter for time sources based on security context. When security requirements are high, the memory device requires time stamps with proper authentication and validation. When security requirements are lower or during initial operations, it can use the host device's time source with less stringent verification, adjusting the reliability parameter dynamically.
Data Source
AI summary
A method for improving accuracy of a time estimate used in digital rights management (DRM) license validation is disclosed. In one embodiment, a memory device receives a request to validate a DRM license stored on the memory device, wherein the DRM license is associated with a time stamp update policy (TUP) that specifies when a new time stamp is needed. Before attempting to validate the DRM license, the memory device determines if a new time stamp is needed based on the TUP associated with the DRM license. If a new time stamp is needed, the memory device receives the new time stamp and then attempts to validate the DRM license using a time estimate based on the new time stamp. Other embodiments are disclosed, and each of the embodiments can be used alone or together in combination.