Software engineering principles have enabled us to continually increase the complexity of the problems that we can solve using software by promoting the sensible use of abstraction, separation, composition and generalisation. Writing software for a public blockchain makes the code we write publicly available for inspection, and potential exploits may result in the loss of funds that the program manages. This unprecedented level of exposure and ease of exploitation requires new methods to improve our confidence in the correctness of the code that we write. This paper explores the main current techniques used to achieve this increased level of confidence, especially in the area of programming language design, starting from the first Turing Complete blockchain implementation Ethereum, and ending with some of the more principled approaches, Scilla and Rholang.
Miha E. Habič, Joel David Hamkins, Lukas Daniel Klausner, Jonathan L. Verner · 5 authors
Given a countable model of set theory, we study the structure of its generic multiverse, the collection of its forcing extensions and ground models, ordered by inclusion. Mostowski showed that any finite poset embeds into the generic multiverse while preserving the nonexistence of upper bounds. We obtain several improvements of his result, using what we call the blockchain construction to build generic objects with varying degrees of mutual genericity. The method accommodates certain infinite posets, and we can realize these embeddings via a wide variety of forcing notions, while providing control over lower bounds as well. We also give a generalization to class forcing in the context of second-order set theory, and exhibit some further structure in the generic multiverse, such as the existence of exact pairs.
In this vision paper, we present an approach that makes it possible to protect developed ideas and early concepts even during their systematical development. We take the Design Thinking process as an example, in which interfaces are used for individual stages (understand, observe, define, ideate, prototype, test) to digitally record verbal, written or sketched, and even modeled or constructed outcome. This outcome is recorded and linked to the originating person. To guarantee both proof-of-existence and proof-of-origin, a unique hash is generated from each digital artifact stored and embedded into the Bitcoin Blockchain by the OriginStamp decentralized trusted timestamping service. Once this unique fingerprint is embedded in a transaction in the underlying Blockchain network, it can be proven where particular contributions originated due to the characteristics of Blockchain architecture. By setting up a decentralized tamper-proof means of record keeping, the entire innovation chain from the first ideation to the beginning of production is verifiably stored. By providing a clear proof-of-origin, all innovators (even competitors) could continue to work on existing problem-solving process and add their contribution proportionately, depending on the state of innovation development. This concept enables an Open Innovation ecosystem, which has the potential to increase the innovation potential of companies immensely. Additionally, inventions that are not patentable because they do not comply with the strict regulations of patent law can still be published and protected because the information about the origin of the respective contribution is guaranteed.
Open access
Computability, Logic, AI Algorithms
Physical Unclonable Functions (PUFs) and Hardware Security
Distributed ledger technologies (DLT) – commonly called blockchain – have rapidly come to prominence as a new way to store and control data. But what benefits does blockchain offer to biometric systems developers and users, and how can biometrics be integrated into DLT systems to achieve better security, scalability and privacy?
We present two models of the block chain of Bitcoin in the interactive theorem prover Agda. The first one is based on a simple model of bank accounts, while having transactions with multiple inputs and outputs. The second model models transactions, which refer directly to unspent transaction outputs, rather than user accounts. The resulting blockchain gives rise to a transaction tree. That model is formalised using an extended form of induction-recursion, one of the unique features of Agda. The set of transaction trees and transactions is defined inductively, while simultaneously recursively defining the list of unspent transaction outputs. Both structures model standard transactions, coinbase transactions, transaction fees, the exact message to be signed by those spending money in a transaction, block rewards, blocks, and the blockchain, and the second structure models as well maturation time for coinbase transactions and Merkle trees. Hashing and cryptographic operations and their correctness are dealt with abstractly by postulating corresponding operations. An indication is given how the correctness of this model could be specified and proven in Agda.
Authentication over insecure public networks or with untrusted servers raises more concerns in privacy and security.Modern algebra is one of the significantfields of mathematics. It is a combination of techniques used for a variety of applications including the process of the manipulation of the mathematical categories. In addition,modern algebra deals in depth with the study of abstractions such as groups, rings and fields,the main objective of this article is to provide a novel algebraic verification protocol using ring theory. The protocol is blind, meaning that it detects only the identity, and no additional information will be known anything about the prover (the biometric) to the authenticating server or vice-versa. More officially a blind authentication scheme is a cryptographic protocol that comprises of two parties, a user (the prover) that wants to achieve having signs on her messages, and a signer (the verifier) that is in ownership of his secret signing key. In this paper, we employ the algebraic structure called central Armendariz rings to design a neoteric algorithm for zero knowledge proof. The proposed protocol is established and illustrated through numerical example, and its soundness and completeness are proved.This method gave two important properties for the central Armendariz zero knowledge protocol compared with other known protocols.
We present a formalization of blockchain as a state machine, focusing upon permissionless blockchains due to general audience awareness of its most popular implementation, Bitcoin (permissioned blockchains are treated similarly without loss of generality). After presenting a typical Bitcoin transaction workflow, a general blockchain state representation is derived. It is demonstrated that the proper mathematical object defining the state of a blockchain is a topological fiber bundle, because it is not possible to globally `parametrize' blocks (or ledgers of blocks) by time due to their dependence upon cryptographic hash functions. In addition, we specify a general transition function between blockchain states that is agnostic to the consensus mechanism used to write blocks into the ledger, and which is probabilistic in nature, so that blockchain may be regarded as a probabilistic state machine. We then interpret agents (both human and code-based, such as `chaincode', `smart contracts', or other artificial intelligence) as automata interacting with blockchain technology, drawing upon the theory of non-cooperative repeated interaction games. Finally, blockchain as a hierarchy of state machines is defined, and future research directions are presented using this hierarchy as a point of departure for modeling blockchain dynamics.
We study the problem of argument systems, where a computationally weak verifier outsources the execution of a computation to a powerful but untrusted prover, while being able to validate that the result was computed correctly through a proof generated by the prover. In addition, the zero-knowledge property guarantees that proof leaks no information about the potential secret input from the prover. Existing efficient zero-knowledge arguments with sublinear verification time require an expensive preprocessing phase that depends on a particular computation, and incur big overhead on the prover time and prover memory consumption. This thesis proposes new constructions for zero-knowledge arguments that overcome the above problems. The new constructions require only a one time preprocessing and can be used to validate any computations later. They also reduce the overhead on the prover time and memory by orders of magnitude. We apply our new constructions to build a verifiable database system and verifiable RAM programs, leading to significant improvements over prior work.
In joint work with Rainer Steinwandt and Dominique Unruh, we look at how the notion of perfect zero-knowledge proof leads to an assumption about probabilistic Turing machines. We prove a theorem in commutative algebra which shows that this assumption is not valid.
Abstract This paper argues that many so‐called digital technologies can be construed as notational technologies, explored through the example of Monegraph, an art and digital asset management platform built on top of the blockchain system originally developed for the cryptocurrency bitcoin. As the paper characterizes it, a notational technology is the performance of syntactic notation within a field of reference, a technologized version of what Nelson Goodman called a “notational system.” Notational technologies produce abstracted entities through positive and reliable, or constitutive, tests of socially acceptable meaning. Accordingly, this account deviates from typical narratives of blockchains (usually characterized as Turing or state machines), instead demonstrating that blockchain technologies are effective at managing digital assets because they produce abstracted identities through the performance of notation. Since notational technologies rely on configurations of socially acceptable meaning, this paper also provides a philosophical account of how blockchain technologies are socially embedded.
Open access
Blockchain Technology Applications and Security
Neuroethics, Human Enhancement, Biomedical Innovations
Abstract This article introduces the symposium “Toward a Philosophy of Blockchain,” which provides a philosophical contemplation of blockchain technology, the digital ledger software underlying cryptocurrencies such as bitcoin, for the secure transfer of money, assets, and information via the Internet without needing a third‐party intermediary. The symposium offers philosophical scholarship on a new topic, blockchain technology , from a variety of perspectives. The philosophical themes discussed include mathematical models of reality, signification, and the sociopolitical institutions that structure human life and interaction. The symposium also investigates the metaphilosophical theme of how to create a philosophy of anything , specifically a new topic such as blockchain technology. Repeated themes are identified, in all areas of philosophical inquiry (ontology, epistemology, and axiology), and conceptual resources are elaborated to contribute to a philosophical understanding of blockchain technology. Thus, philosophy as a metaphilosophical approach is shown to be able to provide an understanding of the conceptual, theoretical, and foundational dimensions of novelty and emergence in the world, with a particular focus on blockchain technology.
We consider a problem we call StateIsomorphism: given two quantum states of n qubits, can one be obtained from the other by rearranging the qubit subsystems? Our main goal is to study the complexity of this problem, which is a natural quantum generalisation of the problem StringIsomorphism. We show that StateIsomorphism is at least as hard as GraphIsomorphism, and show that these problems have a similar structure by presenting evidence to suggest that StateIsomorphism is an intermediate problem for QCMA. In particular, we show that the complement of the problem, StateNonIsomorphism, has a two message quantum interactive proof system, and that this proof system can be made statistical zero-knowledge. We consider also StabilizerStateIsomorphism (SSI) and MixedStateIsomorphism (MSI), showing that the complement of SSI has a quantum interactive proof system that uses classical communication only, and that MSI is QSZK-hard.
Multi-agents systems communication is a technology, which provides a way for multiple interacting intelligent agents to communicate with each other and with environment. Multiple-agent systems are used to solve problems that are difficult for solving by individual agent. Multiple-agent communication technologies can be used for management and organization of computing fog and act as a global, distributed operating system. In present publication we suggest technology, which combines decentralized P2P BOINC general-purpose computing tasks distribution, multiple-agents communication protocol and smart-contract based rewards, powered by Ethereum blockchain. Such system can be used as distributed P2P computing power market, protected from any central authority. Such decentralized market can further be updated to system, which learns the most efficient way for software-hardware combinations usage and optimization. Once system learns to optimize software-hardware efficiency it can be updated to general-purpose distributed intelligence, which acts as combination of single-purpose AI.
We demonstrate that the Bitcoin Script language allows not only for primitive recursion, but in the deployment of an Ackerman function and hence the ability to simply recurse in Bitcoin script, we show that the script system is Turing complete. From this, we introduce a new class of Turing Machine, the PTTM or probabilistic Total Turing machine and note that Bitcoin acts as a decider or Total Turing Machine which allows us to find a NIZKPoK that can act as a TM based verifier to a Non-Interactive Proof that is run on an external and non-associated TM as a proof system. Bitcoin can extend to securely offer contracts such as best fit solutions to common logistic systems and optimisation problems including the Travelling Salesman class of problems and to the optimisation of systems. This can be offered as an open or time bound contract that guarantees payment and can be solved which allowing Pseudonymity of the bidder.
Several Multi-Prover Interactive Proofs (MIPs) found in the literature contain proofs of soundness that are lacking. This was first observed [1] in which a notion of Prover isolation is defined to partly address the issue. Furthermore, some existing Zero-Knowledge MIPs suffer from a catastrophic flaw: they outright allow the Provers to communicate via the Verifier. Consequently, their soundness claims are now seriously in doubt, if not plain wrong. This paper outlines the lack of isolation and numerous other issues found in the (ZK)MIP literature. A follow-up paper will resolve most of these issues in detail.
The concept of a Turing machine has been well defined. It would be sufficient to show that Bitcoin uses a dual stack architecture that acts as a dual counter machine. Such systems have already been demonstrated as being Turing complete. We demonstrate that Bitcoin script is a minimal family of which λ and R are members. Further using the compositional product rule and the iteration rule we demonstrate that Bitcoin scripting is Turing complete with the limitations imposed on any realworld computer. This limitation is that there cannot be an infinite tape. Iterations can be simulated using an “unrolled” loop function with allocation to the “Alt” stack. As the product rule states that if A, B are machines, then A.B is also a machine. The iteration rule shows that if A is a machine then (A) is also a machine. Further the minimum power of A under which the observed square of the final configuration is blank. The consequence of these rules is that for every partial recursive function of in variables we can show that it can be evaluated by machine of the proposed family.
Since Bitcoin was launched in 2009, several new cryptocurrencies have been initiated with variations to Bitcoin's original design. Although Bitcoin still remains the most prominent actor in the market, some technical problems have been raised to the design of the protocol. The objective of this thesis is to determine whether the newer cryptocurrencies handle the technical problems of Bitcoin, or if they also suffer from the same issues. Instead of evaluating several cryptocurrencies for this comparison, the cryptocurrency Ethereum has been chosen as a proxy for the others. Ethereum was started in 2014, is widely backed in the community and is second in line to Bitcoin when it comes to market capitalization. \n\nAs a basis for the comparative analysis a rigorous study of the Bitcoin and Ethereum protocols have been performed, and parallel descriptions of the systems have been devised. Three technical problem have shaped the focus of the analysis: computational waste, concentration of power and ambiguity of transactions. Real world statistical data has been gathered and synthesized to enlighten the findings in the comparison. The main result of the comparison is that both systems suffer from the same problems to a certain degree, due to the fact that they utilize the same consensus mechanism. However, Ethereum utilizes several newer techniques to try and reduce the severity of these problems compared to Bitcoin, with varying degrees of success.
Bitcoin is a digital currency and payment system based on classical cryptographic technologies which works without a central administrator such as in traditional currencies. It has long been questioned what the impact of quantum computing would be on Bitcoin, and cryptocurrencies in general. Here, we analyse three primary directions that quantum computers might have an impact in: mining, security, and forks. We find that in the near-term the impact of quantum computers appear to be rather small for all three directions. The impact of quantum computers would require considerably larger number of qubits and breakthroughs in quantum algorithms to reverse existing hash functions.
The paper deals with cryptocurrencies and trading. Main goal of this article is to introduce strategy for automated trading on cryptocurrency exchange market. For this purpose we will use algorithm based of Floyd-Warshall algorithm. Article is introductory and can this method can be developed in the future. First, a general introduction to cryptocurrencies is given from the programmer's point of view, some statistics data and figure representing volatility of exchange. Then the article describes some basic strategies for automated trading. Also explained is the algorithm Floyd-Warshall and its modifications for automation arbitrage. An illustrative example is given and a trading algorithm is listed.
Kriptovalute su digitalni novac utemeljen na kriptografiji i decentraliziranom sustavu. Postoje samo u elektroničkom obliku kao jedinstveni digitalni novčići ("tokeni"). Iza njih ne stoji autoritet države niti ih je moguće svojevoljno proizvesti. Rad se fokusira na značajkama, postavkama, razvoju i svim međuodnosima važnih ekonomskih faktora koji utječu na kriptovalute. U prvom poglavlju navedena su obilježja kriptovaluta. Drugo poglavlje daje primjere i govori o primjeni kriptovaluta u svakodnevnom životu. U trećem poglavlju je raspravljano o trenutnim i budućim regulacijama najmoćnijih zemalja svijeta (G20) , kao i njihovoj zajedničkoj suradnji u želji za jedinstvenim i standardiziranim pravilima, a sve u svrhu što kvalitetnijeg nadzora nad kriptovalutama kako bi se spriječile malverzacije i zaštitili potrošači. Četvrto poglavlje govori o inicijalnoj ponudi kovanica, a peto poglavlje je namijenjeno sigurnosti kriptovaluta. Cilj istraživanja je utvrditi koliko je studentska populacija upoznata i usmjerena prema novim oblicima digitalnog novca, koje značajke kriptovaluta smatraju pozitivnima, a koje negativnima i u kojoj su mjeri investirali ili su spremni investirati dio svojih ulaganja u kriptovalute i sl. Metode istraživanja korištene u radu su kompilacija na temelju proučavanja postojeće literature o temi rada, prikupljanje i analiza podataka vezanih uz kriptovalute, ponajprije podataka vezanih uz cijene i tržišnu kapitalizaciju, anketiranje studenata Ekonomskog fakulteta u Rijeci i metoda dedukcije putem koje su pokazane sve važne karakteristike i obilježja kriptovaluta. Na temelju provedene ankete u kojoj je sudjelovalo 90 studenata Ekonomskog fakulteta u Rijeci zaključak toga dijela istraživanja je da je mlada populacija dobro upoznata s kriptovalutama i njenim glavnim značajkama, ali i određenim nedostatkom informiranosti o tehnologiji (trećina studenata nije čula za pojam "blockchain") i nedovoljnoj odlučnosti oko investiranja i trgovanja u kriptovalute. Povrh toga, dokazan je i negativan utjecaj hakerskih napada i određenih kriminalnih radnji, kao i nestabilnost tržišne cijene na povjerenje studenata, ali i ukupne populacije vezane uz globalni financijski sustav u kriptovalute. Ishod istraživanja omogućio je da zaključimo kako su kriptovalute trenutno u ranoj fazi razvoja i nisu se dovoljno implementirale za široku primjenu u trgovini roba i usluga ili općenito kao sredstvo razmjene. Faktor koji je uključen u istraživanje kako bi opisao veličinu, odnosno obujam neke kriptovalute je tržišna kapitalizacija u dolarima. Temeljna ideja ovog rada je informirati čitatelja o pozitivnim i negativnim značajkama koje se se vežu uz kriptovalute. Na taj način čitatelji će biti bolje informirani i educirani o potencijalnom riziku ulaganja u kriptovalute, kao i većoj razini zaštite prilikom posjedovanja neke digitalne valute.