Methods and Tools for Secure Quantum Clouds with a specific Case Study on Homomorphic Encryption

TL;DR

The paper tackles securing cloud-scale quantum services against quantum threats by integrating homomorphic encryption (HE) into Eclipse Qrisp. It analyzes three PQC-based HE schemes—Chen (McEliece variant), GSW (lattice-based), and Quantum One-Time Pad (QOTP)—and demonstrates their feasibility within Qrisp, including architectural patterns and a Flask-based evaluation platform. Empirical results show QOTP offers the best runtime and memory characteristics, while Chen and GSW incur higher overheads; the work also provides a detailed security architecture and operational recommendations (QKD, MFA, RBAC, encrypted storage, standardization). The findings inform practical quantum-cloud designs, highlighting performance-security trade-offs and outlining future directions for broader HE-enabled quantum workloads and threat-adaptive security strategies.

Abstract

The rise of quantum computing/technology potentially introduces significant security challenges to cloud computing, necessitating quantum-resistant encryption strategies as well as protection schemes and methods for cloud infrastructures offering quantum computing time and services (i.e. quantum clouds). This research explores various options for securing quantum clouds and ensuring privacy, especially focussing on the integration of homomorphic encryption (HE) into Eclipse Qrisp, a high-level quantum computing framework, to enhance the security of quantum cloud platforms. The study addresses the technical feasibility of integrating HE with Qrisp, evaluates performance trade-offs, and assesses the potential impact on future quantum cloud architectures. The successful implementation and Qrisp integration of three post-quantum cryptographic (PQC) algorithms demonstrates the feasibility of integrating HE with quantum computing frameworks. The findings indicate that while the Quantum One-Time Pad (QOTP) offers simplicity and low overhead, other algorithms like Chen and Gentry-Sahai-Waters (GSW) present performance trade-offs in terms of runtime and memory consumption. The study results in an overall set of recommendations for securing quantum clouds, e.g. implementing HE at data storage and processing levels, developing Quantum Key Distribution (QKD), and enforcing stringent access control and authentication mechanisms as well as participating in PQC standardization efforts.

Figures (12)

• Figure 1: Typical QKD communication setup
• Figure 2: High availability cloud architecture patterns
• Figure 3: Examples of MFA elements.
• Figure 4: Authorization boundaries for administrator, internal user, and external customer permissions in a quantum cloud system.
• Figure 5: Example architecture of quantum cloud usage for homomorphic addition using the Chen algorithm.