Integrating Remote Quantum Random Number Generator as a Shared Resource into GNU/Linux via D-Bus

The random number generation capabilities of the GNU/Linux operating system are subject to certain limitations. As of Linux version 5.6, /dev/random operates in a non-blocking manner and, as such, no longer satisfies the criteria for a True Random Number Generator (TRNG). While dedicated quantum random number generator (QRNG) hardware is the preferred source of unpredictable entropy, it is often expensive and difficult to deploy in virtualized/cloud environments and Internet of Things (IoT) devices. Furthermore, hardware RNG integration typically requires cryptographic applications to adhere to vendor-specific APIs. This article proposes a user-space integration approach for a shared , potentially remote QRNG device. We develop a QRNG service on top of D-Bus, a ubiquitous inter-process communication framework. It serves as an interface for applications to retrieve true random numbers. Communication with the remote QRNG device occurs over mutually authenticated TLS 1.3 channels, protected by post-quantum cryptography (PQC) algorithms. We show, as a proof-of-concept, how the proposed D-Bus service can be integrated into the OpenSSL 3 cryptographic library, demonstrating the use of TRNG in a wide range of Linux applications. Our approach is resistant to entropy starvation attacks, supports sharing a QRNG across host and virtualized environments, requires no kernel-level or system-wide modifications, supports mixing multiple sources of entropy, and configuration of post-processing. It provides applications with a TRNG interface suitable for information-theoretically secure (ITS) use cases.