Semi-Source Independent Quantum Walk Random Number Generation

Semi-source independent quantum random number generators (SI-QRNG) are cryptographic protocols which attempt to extract random strings from quantum sources where the source is under the control of an adversary (but with known dimension) while the measurement devices are fully characterized. This represents a middle-ground between fully-trusted and full-device independence, allowing for fast bit-generation rates with current-day technology, while also providing a strong security guarantee. In this paper we analyze a SI-QRNG protocol based on quantum walks and develop a proof of security. We derive a novel entropic uncertainty relation for this application which is necessary since standard relations actually fail in this case.