Free-Running Oscillator Lock Detection in Random Number Generators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Free Running Oscillators (FROs) used in True Random Number Generators can lock to periodic signals in their environment, reducing the randomness of output samples, which existing post-processing methods may not detect, leading to potentially non-random numbers being considered random.
Innovation Solution
A method to detect locking of FROs by taking periodic samples, storing them, and searching for repeating patterns, counting instances of these patterns, and indicating a lock when a preselected threshold is reached, allowing for adjustments to the FRO operation such as changing frequency or shutting it down.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If post-processing methods are used to generate random numbers from FRO samples, then the ease of operation is improved, but the reliability deteriorates because locking conditions may not be detected
Solution Approach 1:
The patent applies preliminary action by detecting locking conditions in the FRO output samples before they are used in post-processing to generate random numbers. The system continuously monitors samples for repeating patterns and locks the random number generation process if locking is detected, preventing compromised samples from being processed further.
Solution Approach 2:
The patent implements feedback by using the detected locking information to control the random number generation process. When locking is detected through pattern recognition in FRO samples, the system provides feedback to stop or adjust the post-processing operations, ensuring that only non-locked samples are used for generating random numbers.
2Ease of operation
If statistical means are used to check generated random numbers for anomalies, then the ease of operation is improved, but the measurement precision deteriorates because locking may not be revealed
Solution Approach 1:
The patent applies preliminary action by performing locking detection on raw FRO samples before statistical post-processing occurs. This early detection prevents the need for statistical methods to reveal locking, as the locking condition is identified directly from the raw samples through pattern recognition.
Solution Approach 2:
The patent introduces an intermediary locking detection mechanism that operates between the FRO sample generation and the statistical post-processing stages. This intermediary system uses pattern recognition to detect locking conditions, providing more precise measurement than statistical analysis of post-processed values alone.
3Reliability
If FRO locking detection is implemented by searching for repeating patterns in stored samples, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the locking detection function into separate modular components: a sample storage medium for holding FRO output samples, a pattern detection module for searching repeating patterns, and a control module for responding to detected locks. This modular approach improves reliability while managing complexity through functional separation.
Solution Approach 2:
The patent implements self-service by having the system monitor and detect its own locking conditions using its own stored samples. The FRO output samples are stored and then used by the same system to detect whether the FRO has locked, eliminating the need for external monitoring equipment and reducing overall device complexity.
Data Source
Figure 1
Figure 2
AI summary
The detection of locking of a free running oscillator (FRO) is disclosed, including taking periodic samples of the FRO output, storing each new sample in a sample storage medium, each time a new sample is stored searching the stored samples for at least one repeating pattern, counting consecutive sampling instances in which a repeating pattern is found, and indicating when the count reaches a preselected threshold number.