QKD Random Number Generation Using QRNG Seeds and Delayed Replay
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Solution Overview
Problem
Current quantum key distribution systems, particularly satellite-based systems, face challenges in generating and processing high rates of random numbers due to the limitations of quantum random number generators, leading to high power consumption, large size, and complex memory demands, which are exacerbated by the need for real-time post-processing and storage of random numbers.
Innovation Solution
Utilizing a combination of quantum random number generators and cryptographically secure pseudo-random number generators to generate and store random number strings, with a delayed replay mechanism to reduce storage and processing demands, allowing for efficient generation and encoding of pseudo-random numbers at higher rates while maintaining security compliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If quantum random number generators (QRNGs) are used to generate random numbers at high rates, then security compliance is maintained, but the system becomes too slow to support multi GHz photon generation rates
Solution Approach 1:
The system segments the random number generation function into two parts: a QRNG that generates random seeds at a manageable rate, and classical post-processing algorithms that expand these seeds into high-rate random number strings. This segmentation allows the slow but secure QRNG to be combined with fast classical processing to achieve both security and high speed.
Solution Approach 2:
The system performs preliminary random number generation using QRNG to create seed values, then stores these seeds for later use. During actual operation, the stored seeds are retrieved and processed classically to generate random numbers in real-time, eliminating the need for continuous high-rate quantum random number generation.
2Productivity
If a large group of QRNGs is used to collectively generate random numbers at the required rate, then the random number generation rate is sufficient, but the system becomes complicated, expensive, large, heavy and has high power consumption
Solution Approach 1:
The system merges quantum random number generation (for security) with classical pseudorandom number generation (for high rate) into a hybrid architecture. The QRNG provides secure seeds, while classical algorithms expand these seeds into high-rate random number streams, combining the strengths of both approaches without their individual weaknesses.
Solution Approach 2:
The system uses an intermediary classical post-processing stage that takes secure but slow quantum random seeds and transforms them into fast high-rate random number strings. This intermediary layer acts as a bridge between the slow QRNG and the fast requirements of multi GHz photon generation.
3Duration of action of moving object
If random numbers are stored and retrieved for subsequent use in post processing, then QKD sessions can last several minutes, but significant demands are placed on memory/storage within the QKD transmitter
Solution Approach 1:
The system extracts and stores only the essential random seed values generated by the QRNG, rather than storing all the expanded random number strings. These compact seeds are then retrieved and re-processed classically during post-processing, dramatically reducing storage requirements while maintaining session continuity.
4Productivity
If random numbers are read and written to and from memory at high speeds, then real-time post processing is enabled, but extreme demands are placed on processors and massively parallel access to memory is needed
Solution Approach 1:
The system uses inexpensive, simple classical post-processing algorithms that can be implemented with standard processors rather than requiring complex massively parallel processing hardware. These algorithms process the stored random seeds efficiently to generate high-rate random numbers without demanding extreme processor performance or complex memory access patterns.
Data Source
AI summary
A method of operating a quantum key distribution (QKD) system including using a quantum random number generator (QRNG) to generate a random number string (RNS), and storing the RNS; providing the RNS to a first cryptographically secure pseudo-random number generator (CSPRNG) which uses random numbers of the RNS as seeds to generate respective first strings of pseudo-random numbers; using the first strings of pseudo-random numbers to encode photons or pulses transmitted by a transmitter of the QKD system; after a predetermined delay, providing the stored RNS to a second CSPRNG which uses random numbers of the RNS as seeds to generate respective second strings of pseudo-random numbers, the second CSPRNG identically configured to the first CSPRNG; using the second strings of pseudo-random numbers, together with information regarding encoded photons or pulses received by a receiver of the QKD system, to agree secure keys between the transmitter and the receiver.