In this paper, we introduce a new approach to fix the validation of a block and the assignment of a new block in a blockchain infrastructure by using a novel negotiation procedure. The block validation and assignment are reached thanks to negotiation procedures based on an extended probability environment. Also, by using a multiscale approach (typical of Complexity Theory) and Quantum and Relativistic Mechanics, the result appears to solve some of the most relevant questions in the Blockchain context, which are the democracy and the randomness of the validator of a block and the assignment of the new one. The selection of actors to mine is invariant concerning the number of addresses, i.e., the coins of owners, which have more chance to be selected generally. This work is the companion of CQKD (Computational Quantum Key Distribution), as we will see in the introduction, where we considered the infrastructural question of the key distribution; also, it is a very effective application of the decision and reasoning in incompleteness or uncertainty conditions as described in the previous and prodromic paper as described in the introduction too.
Linear Legendre pseudorandom functions were introduced in 1988 by Damgrd, and higher degree generalisations were introduced by Russell and Shparlinski in 2004. We present new key recovery methods that improve the state of the art for both cases. For degree r 3 we give an attack that runs in time O( p r -3 ) after O( p 3 ) precomputation for the most relevant high degree case; it is based on the action of the group of Mbius transformations on degree r polynomials. For r < 3 we give an O( p r/2 ) attack with O( p r/4 ) oracle queries. In the linear case we recovered the keys for the 64, 74 and 84-bit prime Ethereum challenges, being the first to solve the 84-bit case.
This article integrates existing theory from distributed computing and cryptology with gray literature from industry to provide a comprehensive description of the minimum requirements of a technological solution to the current ethics crisis in academic publishing. The paper argues that such a solution could significantly reduce the biases and misconduct that now exist in the academic peer review process. Theory suggests such a system could operate effectively as a distributed encrypted telecommunications network where nodes are anonymous, do not trust each other, with minimal central authority. To incentivize the academic community to join such a community, the paper proposes a new pseudo-cryptocurrency called litcoin (literature coin). This litcoin-based system would create economic scarcity based on proof of knowledge (POK), which is a synthesis of the proof of work (POW) mechanism used in bitcoin, and the proof of stake (POS) mechanism used in various altcoin communities.
This paper proposes a protocol for lottery and a protocol for auction on quantum Blockchain. Our protocol of lottery satisfies randomness, unpredictability, unforgeability, verifiability, decentralization and unconditional security. Our protocol of auction satisfies bid privacy, posterior privacy, bids' binding, decentralization and unconditional security. Except quantum Blockchain, the main technique involved in both protocols is quantum bit commitment.
This article integrates existing theory from distributed computing and cryptology with anecdotal material from the cryptocurrency industry, to provide a comprehensive description of the minimum requirements of the hypothetical academic blockchain. The paper argues that such a community could significantly reduce the biases and misconduct that now exist in the academic peer review process. Theory suggests such a system could operate effectively as a distributed encrypted telecommunications network where nodes are anonymous, do not trust each other, and there is minimal central authority. To incentivize the academic community to join such a proposed community, the paper proposes a pseudo-cryptocurrency called litcoin (literature coin). This litcoin-based system would create economic scarcity based on proof of knowledge (POK), which is a synthesis of the proof of work (POW) mechanism used in bitcoin, and the proof of stake (POS) mechanism used in various altcoin communities. The paper argues that the proposed POK system would enable the academic community to more effectively develop the research it finds valuable.
Cryptocurrencies and distributed registers (blockchains) have recently attracted increased interest among specialists from the widest variety of fields. In turn, the public has generated a pool of regularly asked questions, which have not yet been answered thoroughly. This article provides lines of reasoning with regard to several popular questions linked to this subject. It also addresses issues such as the creation of national cryptocurrencies and use of blockchain technology by businesses and governments. In addition, it analyzes the opinion that cryptocurrencies are a financial pyramid. Finally, it briefly examines the configuration of Bitcoinās distributed register and looks at how this register could be affected by the hypothetical creation of a quantum computer.
La tecnologia blockchain nasce nel 2008 con lāannuncio di BitCoin [1], una delle piuĢ diffuse criptovalute. Il ruolo fondamentale della blockchain nellāambito delle criptovalute eĢ quello di garantire lāimpossibilitaĢ di spendere due volte lo stesso valore in transazioni successive, fattispecie che viene indicata nel mondo anglosassone come double spending. Il problema del double spending eĢ di difficile soluzione quando lāinformazione di un valore eĢ espressa in formato digitale, il quale ben si presta alla riproduzione di copie identiche consentendo quindi di spendere quel valore piuĢ volte. Il problema eĢ superabile in presenza di una entitaĢ centralizzata fidata, quale ad esempio una banca, ma nei casi in cui tale intermediario non eĢ disponibile o non ne eĢ auspicabile la presenza, allora eĢ necessario utilizzare altre modalitaĢ. Nellāambito delle criptovalute, la blockchain risolve il problema attraverso un sistema distribuito in cui la verifica formale della validitaĢ della transazione finanziaria non viene affidata ad un intermediario ma viene svolta da un sistema distribuito, costituito da vari nodi gestiti in modo indipendente, i quali devono raggiungere un consenso, cioeĢ una visione unitaria sullo stato dellāintero sistema. La blockchain consente di gestire dati in modo trasparente, immutabile, fidato e tracciabile. La trasparenza eĢ garantita dal fatto che le informazioni in essa contenute siano messe a disposizione dei vari attori coinvolti. LāimmutabilitaĢ della blockchain eĢ dovuta alla sua struttura dati, una volta inserito il blocco non puoĢ piuĢ essere modificato. La fiducia eĢ dovuta al fatto che la blockchain si basa su evidenze crittografiche piuttosto che nella fiducia in una entitaĢ centralizzata ed elimina pertanto la necessitaĢ di intermediari fidati. Ad esempio, in una transazione finanziaria in cui Antonio (A) vuole dare un certo importo a Benedetta (B), le parti si rivolgono alla banca, la quale decrementa il saldo del conto di A dellāimporto da trasferire ed incrementa il saldo di B della medesima quantitaĢ. A e B si fidano entrambi della banca e non hanno alcuna possibilitaĢ di intervento qualora la banca commetta un errore nellāeseguire la transazione. Utilizzando la blockchain non eĢ invece necessario avere fiducia nella banca e A e B possono effettuare una transazione anche se non si fidano tra loro. La tracciabilitaĢ eĢ dovuta al fatto che nella blockchain non eĢ possibile eliminare le informazioni inserite ma soltanto aggiungerne di nuove in coda, pertanto viene mantenuto lo storico delle informazioni. Inoltre, la blockchain eĢ piuĢ efficiente laddove la sua introduzione non richiede piuĢ lāazione di intermediari, eliminando i costi ad essi associati. A seconda della tipologia di blockchain, questa puoĢ essere accessibile da chiunque in lettura (blockchain pubbliche) o da particolari entitaĢ preventivamente identificate (blockchain private). PercheĢ un nodo possa scrivere sulla blockchain eĢ necessario che esso giunga ad un consenso con gli altri nodi. Se i nodi che devono raggiungere il consenso sono appartenenti ad un gruppo chiuso e predefinito allora si dice che la blockchain eĢ di tipo permissioned, in quanto solo chi ha i permessi puoĢ partecipare alla competizione interna tra i nodi per scrivere dati. Le blockchain permissionless, invece, non necessitano di alcuna identificazione preventiva.
This paper applies biomimetic engineering to the problem of permissionless Byzantine consensus and achieves results that surpass the prior state of the art by four orders of magnitude. It introduces a biologically inspired asymmetric Sybil-resistance mechanism, Proof-of-Balance, which can replace symmetric Proof-of-Work and Proof-of-Stake weighting schemes.
The biomimetic mechanism is incorporated into a permissionless blockchain protocol, Key Retroactivity Network Consensus (KRNC), which delivers ~40,000 times the security and speed of today's decentralized ledgers. KRNC allows the fiat money that the public already owns to be upgraded with cryptographic inflation protection, eliminating the problems inherent in bootstrapping new currencies like Bitcoin and Ethereum.
The paper includes two independently significant contributions to the literature. First, it replaces the non-structural axioms invoked in prior work with a new formal method for reasoning about trust, liveness, and safety from first principles. Second, it demonstrates how two previously overlooked exploits, book-prize attacks and pseudo-transfer attacks, collectively undermine the security guarantees of all prior permissionless ledgers.
Blockchain is the underlying technology of Bitcoin that allows a peer-to-peer distributed ledger with security and immutability. The core of a blockchain is the consensus mechanism that sets the rule for nodes in handling the shared data. Implementation of the consensus algorithm depends on the nature of targeted business environment. In this research, the performance of two consensus algorithms, Proof-of-Work (PoW) and Proof-of-Collatz Conjecture (PCC), are studied in the context of a private blockchain. A quantitative analysis on the execution time, deployment time, and latency time are done for 1, 10, 100, 1000, and 10000 transactions and the results are presented. The results shows that PCC takes only (1/1000)thof the execution time that is required for PoW for these different sets of transactions. In addition, these timings are recorded for ten repeated executions for the same sets of transactions, and found that PCC has a nearly consistent execution time.
This work is an exploration of how graphs and permutations can be applied in the context of quantum information processing. In Chapter 2 we consider problems about the permutations of the subsystems of a quantum system. Explicitly, we attempt to understand the problem of determining if two quantum states of N qubits are isomorphic: if one can be obtained from the other by permuting its subsystems. We show that the well known graph isomorphism problem is a special case of state isomorphism. We also show that the complement of state isomorphism, the problem of determining if two states are not isomorphic, can be verified by a quantum interactive proof system, and that this proof system can be made statistical zero knowledge. We also consider the complexity of isomorphism problems for stabilizer states, and mixed states. In Chapter 3 we work with a special class of quantum states called grid states, in an effort to develop a toy model for mixed state entanglement. The key idea with grid states is that they can be represented by what we call a grid-labelled graph, literally, a graph forced to have vertices on a two dimensional grid. We show that whether or not a grid state is entangled can sometimes be determined solely from the structural properties of its corresponding grid-labelled graph. We use the grid state framework to build families of bound entangled states, suggesting that even in this restricted setting detecting entanglement is non-trivial and will require more than a single entanglement criterion.
This chapter considers blockchains as constitutional orders. Blockchains compete and complement with firms, markets, governments, clubs, and the commons. Additionally, their versatility (the constitution can be varied for each application) allow them to adopt the characteristics of other institutions. The authors call this the āuniversal Turing institutionā. The chapter then explores the dynamics of institutional and constitutional innovation in distributed ledgers.
Inspired by the work of Ghadafi and Groth (ASIACRYPT 2017) on a certain type of computational hardness assumptions in cyclic groups (which they call ``target assumptions''), we initiate an analogous work on another type of hardness assumptions, namely the ``knowledge-of-exponent'' assumptions (KEAs). Originally introduced by Damgard to construct practical encryption schemes secure against chosen ciphertext attacks, KEAs have subsequently been used primarily to construct succinct non-interactive arguments of knowledge (SNARKs), and proved to be inherent to such constructions. Since SNARKs (and their zero-knowledge variant, zk-SNARKs) are already used in practice in such systems as the Zcash digital currency, it can be expected that the use of KEAs will increase in the future, which makes it important to have a good understanding of those assumptions. Using a proof technique first introduced by Bellare and Palacio (but acknowledged by them as being due to Halevi), we first investigate the internal structure of the q-power knowledge-of-exponent (q-PKE) family of assumptions introduced by Groth, which is thus far the most general variant of KEAs. We then introduce a generalisation of the q-PKE family, and show that it can be simplified.
Ayushi Sharma, Shashwat Tiwari, Nitin Arora, S. C. Sharma
Blockchain is an emerging technology that can radically improve transactions security at banking, supply chain, and other transaction networks. It's estimated that Blockchain will generate $3.1 trillion in new business value by 2030. Essentially, it provides the basis for a dynamic distributed ledger that can be applied to save time when recording transactions between parties, remove costs associated with intermediaries, and reduce risks of fraud and tampering. This book explores the fundamentals and applications of Blockchain technology. Readers will learn about the decentralized peer-to-peer network, distributed ledger, and the trust model that defines Blockchain technology. They will also be introduced to the basic components of Blockchain (transaction, block, block header, and the chain), its operations (hashing, verification, validation, and consensus model), underlying algorithms, and essentials of trust (hard fork and soft fork). Private and public Blockchain networks similar to Bitcoin and Ethereum will be introduced, as will concepts of Smart Contracts, Proof of Work and Proof of Stack, and cryptocurrency including Facebook's Libra will be elucidated. Also, the book will address the relationship between Blockchain technology, Internet of Things (IoT), Artificial Intelligence (AI), Cybersecurity, Digital Transformation and Quantum Computing. Readers will understand the inner workings and applications of this disruptive technology and its potential impact on all aspects of the business world and society. A look at the future trends of Blockchain Technology will be presented in the book.
Security of data is crucial in nowadays societies. One of the most basic security protocols are the zero-knowledge protocols where a prover convinces a verifier of the knowledge of a secret information without revealing that piece of information. The tradicional approach to prove the security of these protocols is based on the (im)possibility of simulation of the interactions. A more fundamental way to prove the security is based solely on the information conveyed about proof. In order to establish that connection and quantifying the number of possible transformations that one can use in these protocols, we use Kolmogorov complexity and in particular we focus on the incompressibility theorem. In this paper we study the counterpart of this theorem by, instead of providing the number of x such that for a fixed y, Kt(x|y) ā Kt(x), we study for a fixed y the number of x such that Kt(x|y) ā Kt(x). As a second contribution of this paper we present an extension of the results regarding Kolmogorov one-way functions started in [3]. This cryptographic primitives have the property to be easy to compute but hard to invert and are a basilar ingredient for digital security.