Raziel: Private and Verifiable Smart Contracts on Blockchains

Raziel combines secure multi-party computation and proof-carrying code to provide privacy, correctness and verifiability guarantees for smart contracts on blockchains. Effectively solving DAO and Gyges attacks, this paper describes an implementation and presents examples to demonstrate its practical viability (e.g., private and verifiable crowdfundings and investment funds). Additionally, we show how to use Zero-Knowledge Proofs of Proofs (i.e., Proof-Carrying Code certificates) to prove the validity of smart contracts to third parties before their execution without revealing anything else. Finally, we show how miners could get rewarded for generating pre-processing data for secure multi-party computation.Comment: Support: cothority/ByzCoin/OmniLedge

Function-specific schemes for verifiable computation

An integral component of modern computing is the ability to outsource data and computation to powerful remote servers, for instance, in the context of cloud computing or remote file storage. While participants can benefit from this interaction, a fundamental security issue that arises is that of integrity of computation: How can the end-user be certain that the result of a computation over the outsourced data has not been tampered with (not even by a compromised or adversarial server)? Cryptographic schemes for verifiable computation address this problem by accompanying each result with a proof that can be used to check the correctness of the performed computation. Recent advances in the field have led to the first implementations of schemes that can verify arbitrary computations. However, in practice the overhead of these general-purpose constructions remains prohibitive for most applications, with proof computation times (at the server) in the order of minutes or even hours for real-world problem instances. A different approach for designing such schemes targets specific types of computation and builds custom-made protocols, sacrificing generality for efficiency. An important representative of this function-specific approach is an authenticated data structure (ADS), where a specialized protocol is designed that supports query types associated with a particular outsourced dataset. This thesis presents three novel ADS constructions for the important query types of set operations, multi-dimensional range search, and pattern matching, and proves their security under cryptographic assumptions over bilinear groups. The scheme for set operations can support nested queries (e.g., two unions followed by an intersection of the results), extending previous works that only accommodate a single operation. The range search ADS provides an exponential (in the number of attributes in the dataset) asymptotic improvement from previous schemes for storage and computation costs. Finally, the pattern matching ADS supports text pattern and XML path queries with minimal cost, e.g., the overhead at the server is less than 4% compared to simply computing the result, for all our tested settings. The experimental evaluation of all three constructions shows significant improvements in proof-computation time over general-purpose schemes

ARPA Whitepaper

We propose a secure computation solution for blockchain networks. The correctness of computation is verifiable even under malicious majority condition using information-theoretic Message Authentication Code (MAC), and the privacy is preserved using Secret-Sharing. With state-of-the-art multiparty computation protocol and a layer2 solution, our privacy-preserving computation guarantees data security on blockchain, cryptographically, while reducing the heavy-lifting computation job to a few nodes. This breakthrough has several implications on the future of decentralized networks. First, secure computation can be used to support Private Smart Contracts, where consensus is reached without exposing the information in the public contract. Second, it enables data to be shared and used in trustless network, without disclosing the raw data during data-at-use, where data ownership and data usage is safely separated. Last but not least, computation and verification processes are separated, which can be perceived as computational sharding, this effectively makes the transaction processing speed linear to the number of participating nodes. Our objective is to deploy our secure computation network as an layer2 solution to any blockchain system. Smart Contracts\cite{smartcontract} will be used as bridge to link the blockchain and computation networks. Additionally, they will be used as verifier to ensure that outsourced computation is completed correctly. In order to achieve this, we first develop a general MPC network with advanced features, such as: 1) Secure Computation, 2) Off-chain Computation, 3) Verifiable Computation, and 4)Support dApps' needs like privacy-preserving data exchange

Security in Mobile Networks: Communication and Localization

Nowadays the mobile networks are everywhere. The world is becoming more dependent on wireless and mobile services, but the rapid growth of these technologies usually underestimates security aspects. As wireless and mobile services grow, weaknesses in network infrastructures become clearer. One of the problems is privacy. Wireless technologies can reduce costs, increase efficiencies, and make important information more readily and widely available. But, there are also risks. Without appropriate safeguards, these data can be read and modified by unauthorized users. There are many solutions, less and more effective, to protect the data from unauthorized users. But, a specific application could distinguish more data flows between authorized users. Protect the privacy of these information between subsets of users is not a trivial problem. Another problem is the reliability of the wireless service. Multi-vehicle systems composed of Autonomous Guided Vehicles (AGVs) are largely used for industrial transportation in manufacturing and logistics systems. These vehicles use a mobile wireless network to exchange information in order to coordinate their tasks and movements. The reliable dissemination of these information is a crucial operation, because the AGVs may achieve an inconsistent view of the system leading to the failure of the coordination task. This has clear safety implications. Going more in deep, even if the communication are confidential and reliable, anyway the positioning information could be corrupted. Usually, vehicles get the positioning information through a secondary wireless network system such as GPS. Nevertheless, the widespread civil GPS is extremely fragile in adversarial scenarios. An insecure distance or position estimation could produce security problems such as unauthorized accesses, denial of service, thefts, integrity disruption with possible safety implications and intentional disasters. In this dissertation, we face these three problems, proposing an original solution for each one

Bot Contracts

In this Article, we explain why the transactions commonly known as “smart contracts” are better understood as “bot contracts.” Taking an interdisciplinary approach, we show why the “smart contracts” moniker is misdescriptive in two important ways. First, these transactions are automated, not smart. Second, they do not afford parties many enforcement rights and defenses that one expects from common law contractual relationships. To fully understand these transactions, it is important to appreciate how the term “smart contracts” differs from what the technology delivers. Our review of the technology explains that these transactions have tremendous practical utility in reducing risk and avoiding the uncertainty and expense of seeking judicial enforcement. However, the electronic processes that occur in this category are not smart in the sense of being thoughtful, creative, or even amenable to change. They are programmed to follow preset instructions and execute automatically. Once the conditions for performance under a smart contract occur, performance cannot be stopped. Because these transactions are automated, they lack features and defenses available to those who enter into typical contractual relationships. Common law contracts are sets of promises or obligations that may be enforced by a court. However, once a smart contract is set in motion, no person or court can reverse the transaction. In this way, smart contracts differ fundamentally from traditional contracts because they leave no room for judicial intervention. By design, they evade the risk of what a court may do in fashioning a remedy. Courts have no power to set the transaction aside if it was induced by fraud or if another common law defense would, under other circumstances, render the transaction void or voidable. Although the term “smart contract” appears to have taken hold, we propose that these transactions are better thought of as “bot” or “automated” agreements. Reframing these transactions in this way would reset expectations in line with what the technology can deliver. Adopting this more encompassing terminology will send a strong informational signal that avoids misrepresenting the abilities of these agreements by more accurately communicating that they execute automatically and eliminate both the risks and benefits that accompany traditional common law contracts

A Critical Investigation into Identifying Key Focus Areas for the Implementation of Blockchain Technology in the Mining Industry

Thesis (PhD)--University of Pretoria, 2023.The value of digital information is ever-increasing as more companies utilize digital technologies such as Artificial Intelligence (AI) and the Internet of Things (IoT) to gain deeper insight into their business operations and drive productivity gains. It is therefore important to safeguard and ensure the integrity of digital information exchange. Blockchain technology (BCT) was identified as potentially providing the mining industry with a trusted system for securely exchanging digital value. However, there is little evidence or understanding of how/where BCT can be implemented and what benefits the industry could obtain. This research study provides a fundamental understanding of what the technology is in order to identify the associated capabilities and potential application benefits for the mining industry. From a technology push perspective, blockchain capabilities are used to evaluate how the technology’s value drivers map to the mining industries core value chain processes. This was done to identify potential focus areas within the mining enterprise for further research and development of blockchain applications.ARMMining EngineeringMEngUnrestricte