Blockchains, Volume 3, Issue 2 (June 2025) – 3 articles

We examine the use of a Geometric Distribution for pre-calculating the publication deadlines of blocks in a simulation of proof-of-work Blockchain. Specifically, we focus on Discrete-Event Simulation, where the simulator identifies events to be simulated, calculates their deadlines, places them in an Event Queue ordered by deadline, and processes them sequentially. In Blockchain, these events include the publication and reception of a block by each Miner. While a Geometric Distribution allows the calculation of block publication deadlines in the absence of Difficulty updates, in the case of evolving Difficulty, it must be extended to a non-homogeneous Geometric Distribution. To address this issue, we introduce the Geometric Distribution with a Variable Probability, a non-homogeneous Geometric Distribution that enables the calculation of block publication deadlines in the presence of Difficulty Regulation—a distinctive feature of proof-of-work Blockchain. We then present the architecture and operating principles of a Discrete-Event Simulator based on this distribution, along with simulation results that validate our approach. Full article

Blockchain technology has evolved beyond financial transactions to revolutionize trust systems. This paper presents a blockchain-based model for decentralized rental agreements and dispute resolution (DRADR). By leveraging smart contracts and implementing two distinct arbitration approaches, our model offers flexible solutions for rental agreement automation, transparency enhancement, and impartial dispute resolution. Our study provides a comprehensive technical analysis of both approaches through theoretical frameworks, smart contract implementation, game-theoretic modeling, and comparative evaluation across multiple legal jurisdictions. We explore the potential of blockchain technology to address long-standing challenges in traditional rental systems, such as power imbalances, inefficiencies, and legal disputes. Key contributions include the integration of decentralized and local justice systems; a detailed game-theoretic analysis of strategic behaviors; and comparative insights into gas efficiency, economic viability, and jurisdictional adaptability across both arbitration approaches. This research paves the way for a more equitable and transparent rental market and contributes to the broader acceptance of blockchain-based solutions in everyday transactions. Full article

This research presents a novel framework and experimental results that combine zero-knowledge proofs (ZKPs) with private blockchain technology to safeguard whistleblower privacy while ensuring secure digital evidence submission and verification. For example, whistleblowers involved in corporate fraud cases can submit sensitive financial records anonymously while maintaining the credibility of the evidence. The proposed framework introduces several key innovations, including a private blockchain implementation utilising proof-of-work (PoW) consensus to ensure immutable storage and thorough scrutiny of submitted evidence, with mining difficulty dynamically aligned to the sensitivity of the data. It also features an adaptive difficulty mechanism that automatically adjusts computational requirements based on the sensitivity of the evidence, providing tailored protection levels. In addition, a unique two-phase validation process is incorporated, which generates a digital signature from the evidence alongside random challenges, significantly improving security and authenticity. The integration of ZKPs enables iterative hash-based verification between parties (Prover and Verifier) while maintaining the complete privacy of the source data. This research investigates the whistleblower’s niche in traditional digital evidence management systems (DEMSs), prioritising privacy without compromising evidence integrity. Experimental results demonstrate the framework’s effectiveness in preserving anonymity while assuring the authenticity of the evidence, making it useful for judicial systems and organisations handling sensitive disclosures. This paper signifies notable progress in secure whistleblowing systems, offering a way to juggle transparency with informant confidentiality. Full article