Pseudo-Random Number Generator Seed Generation Using Oscillator Startup Transients
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Solution Overview
Problem
The generation of true random numbers in security controllers, such as smart cards, is complex and costly, leading to the use of pseudo-random number generators that can be reverse-calculated if the initial value is known, posing a significant security risk.
Innovation Solution
An apparatus and method that generate an initial value for a pseudo-random number generator using an oscillator circuit and period counter, where the initial value is determined during the start-up phase of the oscillator, based on parameters like temperature and supply voltage, making it unpredictable and difficult to reverse-calculate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a true random-number generator is implemented using analogue circuit elements, then true random numbers can be generated, but the implementation becomes complex and cost-intensive
Solution Approach 1:
The patent replaces the mechanical/physical analogue oscillator system with a digital pseudo-random number generator that uses a digital oscillator and counts cycles during the startup transient. This substitution maintains the randomness benefit while eliminating the need for complex analogue circuitry, resolving the contradiction between randomness quality and device complexity
Solution Approach 2:
The patent changes the parameter being measured from the continuous amplitude of an analogue noise signal to the discrete count of oscillator cycles during a specific time interval (startup transient). This parameter transformation allows digital implementation while preserving the unpredictable nature of the random value, thus reducing device complexity without sacrificing randomness quality
2Ease of manufacture
If a pseudo-random number generator is used with a known initial value, then it can be fully implemented in digital technique, but the sequence becomes predictable and vulnerable to backward calculation
Solution Approach 1:
The patent performs the random initial value generation during the startup transient phase, before the pseudo-random number generator is initialized and before any predictable sequence generation begins. This preliminary action ensures the seed is established under unpredictable conditions, preventing backward calculation while maintaining full digital implementation
Solution Approach 2:
The patent introduces an intermediate measurement step that counts the number of oscillator cycles during the startup transient. This intermediate value serves as an unpredictable seed that mediates between the digital implementation requirements and the security requirements, allowing the system to achieve both ease of manufacture and reliability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for the economical generation of a random initial value for pseudo-random number generators without additional analogue components, enhancing security by making backward calculation more difficult.
Implementation Method 1
an oscillator circuit (110) for generating an oscillator signal
Data Source
AI summary
Apparatus and method for generating an initial value for a pseudo-random number generator, with an oscillator configured to generate an oscillator signal; and a generator configured to generate the initial value based on the oscillator signal at least during part of a transient of the oscillator.