Critical Internet of Things (IoT) deployments in domains such as mining generate large volumes of data that multiple stakeholders rely on. Cloud-centric backup solutions offer limited transparency, concentrate control in one provider, and create single points of failure. We present FileTrust, a blockchain-based auditable backup framework that preserves integrity, confidentiality, availability, and auditability of IoT data in low-trust, multi-stakeholder environments. FileTrust combines an Information Dispersal Algorithm (IDA) with the InterPlanetary File System (IPFS) for distributed storage and uses blockchain and threshold cryptography to enforce access control. Its operation has three procedures: (i) data publishing, where data are dispersed via IDA, stored in IPFS, and referenced on-chain via content identifiers (CIDs); (ii) key establishment and CID protection, where shareholders run verifiable secret sharing (VSS)-based distributed key generation (DKG) to establish a threshold public key, and each CID is protected through a hybrid key-encapsulation mechanism and data-encapsulation mechanism (KEM-DEM) structure in which a fresh per-CID symmetric key encrypts the CID while threshold ElGamal (TElG) encapsulates that key before the resulting tuple is recorded on-chain; and (iii) data access, where shareholders perform threshold operations over the protected key material for authorized requesters, who recover plaintext CIDs, retrieve IPFS fragments, and reconstruct data using the IDA threshold. We formalize the system and threat model, implement FileTrust as Ethereum smart contracts, and evaluate gas cost and storage overhead. The results show that FileTrust provides verifiable, stakeholder-driven backup access without relying on a trusted cloud provider.

MOTIVATION: The affordability of genome sequencing and the widespread availability of genomic data have opened up new medical possibilities. Nevertheless, they also raise significant concerns regarding privacy due to the sensitive information they encompass. These privacy implications act as barriers to medical research and data availability. Researchers have proposed privacy-preserving techniques to address this, with cryptography-based methods showing the most promise. However, existing cryptography-based designs lack (i) interoperability, (ii) scalability, (iii) a high degree of privacy (i.e. compromise one to have the other), or (iv) multiparty analyses support (as most existing schemes process genomic information of each party individually). Overcoming these limitations is essential to unlocking the full potential of genomic data while ensuring privacy and data utility. Further research and development are needed to advance privacy-preserving techniques in genomics, focusing on achieving interoperability and scalability, preserving data utility, and enabling secure multiparty computation. RESULTS: This study aims to overcome the limitations of current cryptography-based techniques by employing a multi-key homomorphic encryption scheme. By utilizing this scheme, we have developed a comprehensive protocol capable of conducting diverse genomic analyses. Our protocol facilitates interoperability among individual genome processing and enables multiparty tests, analyses of genomic databases, and operations involving multiple databases. Consequently, our approach represents an innovative advancement in secure genomic data processing, offering enhanced protection and privacy measures. AVAILABILITY AND IMPLEMENTATION: All associated code and documentation are available at https://github.com/farahpoor/smkhe.

The field of genomic research has considerably grown in the recent years due to the unprecedented advances brought about by Next Generation Sequencing (NGS) and the need and increasing widespread use of outsourced processing. But this rapid increase also poses severe privacy risks due to the inherently sensitive nature of genomic information. In this work, we address privacy-preserving genetic susceptibility tests outsourced to an untrustworthy party, enhancing previous approaches in terms of computation and communication efficiency by leveraging the use of somewhat homomorphic lattice encryption and relinearization operations to achieve more efficient constructions. Additionally, we also propose a more general construction which deals with several different medical units (such as pharmaceutical companies or hospitals), managing patients' consent to the disclosure of test results for each of these units, which may dynamically join the system. Our scheme features an attribute-based homomorphic cryptosystem which enables enforcing the patient's access policy referred to the different medical units.