Bitcoin Spectrum
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
White Paper of Bitcoin Ultimatum Introduction
White Paper of Bitcoin Ultimatum Introduction 1. Problematic of the Blockchain 4. Bitcoin Ultimatum Architecture industry 4.1. Network working principle 1.1. Transactions Anonymity 4.1.1. Main Transaction Types 1.2. Insufficient Development of Key Aspects of the 4.1.1.1. Public transactions Technology 4.1.1.2. Private transactions 1.3. Centralization 4.1.2. Masternode Network 1.4. Mining pools and commission manipulation 4.2. How to become a validator or masternode in 1.5. Decrease in Transaction Speeds BTCU 4.3. Network Scaling Principle 2. BTCU main solutions and concepts 4.4. Masternodes and Validators Ranking System 4.5. Smart Contracts 2.1. Consensus algorithm basis 4.6. Anonymization principle 2.2. Leasing and Staking 4.7. Staking and Leasing 2.3. Projects tokenization and DeFi 4.7.1. Staking 2.4. Transactions Privacy 4.7.2. Leasing 2.5. Atomic Swaps 4.7.2 Multileasing 4.8. BTCU Technical Specifications 3. Executive Summary 4.8.1. Project Stack 4.8.2. Private key generation algorithm 5. Bitcoin Ultimatum Economy 5.1. Initial Supply and Airdrop 5.2. Leasing Economy 5.3. Masternodes and Validators Commission 5.4. Transactions Fee 6. Project Roadmap 7. Legal Introduction The cryptocurrency market is inextricably tied to the blockchain – its fundamental and underlying technology. The modern market is brimming with an abundance of blockchain protocols, algorithms, and concepts, all of which have fostered the development of a wide variety of services and applications. The modern blockchain market offers users an alternative to both established financial systems and ecosystems/infrastructures of applications and services. -
Proof of 'X' and Hash Functions Used
Top 20 Cryptocurrencies on Aggregate market value - Proof of ‘X’ and Hash functions used - 1 ISI Kolkata BlockChain Workshop, Nov 30th, 2017 CRYPTOGRAPHY with BlockChain - Hash Functions, Signatures and Anonymization - Hiroaki ANADA*1, Kouichi SAKURAI*2 *1: University of Nagasaki, *2: Kyushu University Acknowledgements: This work is supported by: Grants-in-Aid for Scientific Research of Japan Society for the Promotion of Science; Research Project Number: JP15H02711 Top 20 Cryptocurrencies on Aggregate market value - Proof of ‘X’ and Hash functions used - 3 Table of Contents 1. Cryptographic Primitives in Blockchains 2. Hash Functions a. Roles b. Various Hash functions used for Proof of ‘X’ 3. Signatures a. Standard Signatures (ECDSA) b. Ring Signatures c. One-Time Signatures (Winternitz) 4. Anonymization Techniques a. Mixing (CoinJoin) b. Zero-Knowledge proofs (zk-SNARK) 5. Conclusion 4 Brief History of Proof of ‘X’ 1992: “Pricing via Processing or Combatting Junk Mail” Dwork, C. and Naor, M., CRYPTO ’92 Pricing Functions 2003: “Moderately Hard Functions: From Complexity to Spam Fighting” Naor, M., Foundations of Soft. Tech. and Theoretical Comp. Sci. 2008: “Bitcoin: A peer-to-peer electronic cash system” Nakamoto, S. Proof of Work 5 Brief History of Proof of ‘X’ 2008: “Bitcoin: A peer-to-peer electronic cash system” Nakamoto, S. Proof of Work 2012: “Peercoin” Proof of Stake (& Proof of Work) ~ : Delegated Proof of Stake, Proof of Storage, Proof of Importance, Proof of Reserves, Proof of Consensus, ... 6 Proofs of ‘X’ 1. Proof of Work 2. Proof of Stake Hash-based Proof of ‘X’ 3. Delegated Proof of Stake 4. Proof of Importance 5. -
Aggregate Cash System: a Cryptographic Investigation Of
Aggregate Cash Systems: A Cryptographic Investigation of Mimblewimble Georg Fuchsbauer1,2, Michele Orrù2,1, and Yannick Seurin3 1 Inria 2 École normale supérieure, CNRS, PSL University, Paris, France 3 ANSSI, Paris, France {georg.fuchsbauer, michele.orru}@ens.fr [email protected] Abstract. Mimblewimble is an electronic cash system proposed by an anonymous author in 2016. It combines several privacy-enhancing techniques initially envisioned for Bitcoin, such as Confidential Transactions (Maxwell, 2015), non-interactive merging of transactions (Saxena, Misra, Dhar, 2014), and cut-through of transaction inputs and outputs (Maxwell, 2013). As a remarkable consequence, coins can be deleted once they have been spent while maintaining public verifiability of the ledger, which is not possible in Bitcoin. This results in tremendous space savings for the ledger and efficiency gains for new users, who must verify their view of the system. In this paper, we provide a provable-security analysis for Mimblewimble. We give a precise syntax and formal security definitions for an abstraction of Mimblewimble that we call an aggregate cash system. We then formally prove the security of Mimblewimble in this definitional framework. Our results imply in particular that two natural instantiations (with Pedersen commitments and Schnorr or BLS signatures) are provably secure against inflation and coin theft under standard assumptions. Keywords: Mimblewimble, Bitcoin, commitments, aggregate signatures. 1 Introduction Bitcoin and the UTXO model. Proposed in 2008 and launched early 2009, Bitcoin [Nak08] is a decentralized payment system in which transactions are registered in a distributed and publicly verifiable ledger called a blockchain. Bitcoin departs from traditional account-based payment systems where transactions specify an amount moving from one account to another. -
Review Articles
review articles DOI:10.1145/3372115 system is designed to achieve common Software weaknesses in cryptocurrencies security goals: transaction integrity and availability in a highly distributed sys- create unique challenges in responsible tem whose participants are incentiv- revelations. ized to cooperate.38 Users interact with the cryptocurrency system via software BY RAINER BÖHME, LISA ECKEY, TYLER MOORE, “wallets” that manage the cryptograph- NEHA NARULA, TIM RUFFING, AND AVIV ZOHAR ic keys associated with the coins of the user. These wallets can reside on a local client machine or be managed by an online service provider. In these appli- cations, authenticating users and Responsible maintaining confidentiality of crypto- graphic key material are the central se- curity goals. Exchanges facilitate trade Vulnerability between cryptocurrencies and between cryptocurrencies and traditional forms of money. Wallets broadcast cryptocur- Disclosure in rency transactions to a network of nodes, which then relay transactions to miners, who in turn validate and group Cryptocurrencies them together into blocks that are ap- pended to the blockchain. Not all cryptocurrency applications revolve around payments. Some crypto- currencies, most notably Ethereum, support “smart contracts” in which general-purpose code can be executed with integrity assurances and recorded DESPITE THE FOCUS on operating in adversarial on the distributed ledger. An explosion of token systems has appeared, in environments, cryptocurrencies have suffered a litany which particular functionality is ex- of security and privacy problems. Sometimes, these pressed and run on top of a cryptocur- rency.12 Here, the promise is that busi- issues are resolved without much fanfare following ness logic can be specified in the smart a disclosure by the individual who found the hole. -
Electronic Cash, Decentralized Exchange, and the Constitution
Electronic Cash, Decentralized Exchange, and the Constitution Peter Van Valkenburgh March 2019 coincenter.org Peter Van Valkenburgh, Electronic Cash, Decentralized Exchange, and the Constitution, Coin Center Report, Mar. 2019, available at https://coincenter.org/entry/e-cash-dex-constitution Abstract Regulators, law enforcement, and the general public have come to expect that cryptocurrency transactions will leave a public record on a blockchain, and that most cryptocurrency exchanges will take place using centralized businesses that are regulated and surveilled through the Bank Secrecy Act. The emergence of electronic cash and decentralized exchange software challenges these expectations. Transactions need not leave any public record and exchanges can be accomplished peer to peer without using a regulated third party in between. Faced with diminished visibility into cryptocurrency transactions, policymakers may propose new approaches to financial surveillance. Regulating cryptocurrency software developers and individual users of that software under the Bank Secrecy Act would be unconstitutional under the Fourth Amendment because it would be a warrantless search and seizure of information private to cryptocurrency users. Furthermore, any law or regulation attempting to ban, require licensing for, or compel the altered publication (e.g. backdoors) of cryptocurrency software would be unconstitutional under First Amendment protections for speech. Author Peter Van Valkenburgh Coin Center [email protected] About Coin Center Coin Center is a non-profit research and advocacy center focused on the public policy issues facing open blockchain technologies such as Bitcoin. Our mission is to build a better understanding of these technologies and to promote a regulatory climate that preserves the freedom to innovate using blockchain technologies. -
Arxiv:1907.02434V1 [Cs.CY] 4 Jul 2019 1 Introduction
Cryptocurrency Egalitarianism: A Quantitative Approach Dimitris Karakostas1,3, Aggelos Kiayias1,3, Christos Nasikas2,4, and Dionysis Zindros2,3 1 University of Edinburgh 2 University of Athens 3 IOHK 4 “ATHENA” Research Center Abstract. Since the invention of Bitcoin one decade ago, numerous cryptocurrencies have sprung into existence. Among these, proof-of-work is the most common mechanism for achieving consensus, whilst a num- ber of coins have adopted “ASIC-resistance” as a desirable property, claiming to be more “egalitarian,” where egalitarianism refers to the power of each coin to participate in the creation of new coins. While proof-of-work consensus dominates the space, several new cryptocurren- cies employ alternative consensus, such as proof-of-stake in which block minting opportunities are based on monetary ownership. A core criti- cism of proof-of-stake revolves around it being less egalitarian by making the rich richer, as opposed to proof-of-work in which everyone can con- tribute equally according to their computational power. In this paper, we give the first quantitative definition of a cryptocurrency’s egalitarian- ism. Based on our definition, we measure the egalitarianism of popular cryptocurrencies that (may or may not) employ ASIC-resistance, among them Bitcoin, Ethereum, Litecoin, and Monero. Our simulations show, as expected, that ASIC-resistance increases a cryptocurrency’s egalitar- ianism. We also measure the egalitarianism of a stake-based protocol, Ouroboros, and a hybrid proof-of-stake/proof-of-work cryptocurrency, Decred. We show that stake-based cryptocurrencies, under correctly se- lected parameters, can be perfectly egalitarian, perhaps contradicting folklore belief. arXiv:1907.02434v1 [cs.CY] 4 Jul 2019 1 Introduction In 2008, Satoshi Nakamoto proposed Bitcoin [25], the first and most suc- cessful cryptocurrency to date. -
A Regulatory System for Optimal Legal Transaction Throughput in Cryptocurrency Blockchains
A Regulatory System for Optimal Legal Transaction Throughput in Cryptocurrency Blockchains Aditya Ahuja Vinay J. Ribeiro Ranjan Pal Indian Institute of Technology Indian Institute of Technology University of Michigan Delhi Bombay Ann Arbor, USA New Delhi, India Mumbai, India [email protected] [email protected] [email protected] ABSTRACT correctness of the underlying computational principles, which are a Permissionless blockchain consensus protocols have been designed basis of the efficacy of these economies. More specifically, in order primarily for defining decentralized economies for the commercial to sustain these cryptocurrency based decentralized economies, trade of assets, both virtual and physical, using cryptocurrencies. blockchain consensus protocols serve as a technical foundation. In most instances, the assets being traded are regulated, which man- Existing blockchain protocols for cryptocurrencies address one dates that the legal right to their trade and their trade value are of (or any combination of) the following system goals: speed, se- determined by the governmental regulator of the jurisdiction in curity and decentralization. Unfortunately, these system goals are which the trade occurs. Unfortunately, existing blockchains do not necessary but insufficient. Illegal activities propelled through the formally recognise proposal of legal cryptocurrency transactions, as strategic use of blockchain based cryptocurrencies, is a serious part of the execution of their respective consensus protocols, result- problem staring at the face of many world governments today ing in rampant illegal activities in the associated crypto-economies. [47]. These illegal activities exploit the permissionless nature of In this contribution, we motivate the need for regulated blockchain the blockchain networks for illegal trade, to strategically defeat consensus protocols with a case study of the illegal, cryptocurrency regulation by obfuscating the jurisdictions of the blockchain users based, Silk Road darknet market. -
One-Out-Of-Many Proofs: Or How to Leak a Secret and Spend a Coin
One-out-of-Many Proofs: Or How to Leak a Secret and Spend a Coin Jens Groth1? and Markulf Kohlweiss2 1 University College London 2 Microsoft Research Abstract. We construct a 3-move public coin special honest verifier zero-knowledge proof, a so-called Sigma-protocol, for a list of commit- ments having at least one commitment that opens to 0. It is not required for the prover to know openings of the other commitments. The proof system is efficient, in particular in terms of communication requiring only the transmission of a logarithmic number of commitments. We use our proof system to instantiate both ring signatures and zerocoin, a novel mechanism for bitcoin privacy. We use our Sigma-protocol as a (linkable) ad-hoc group identification scheme where the users have public keys that are commitments and demonstrate knowledge of an opening for one of the commitments to unlinkably identify themselves (once) as belonging to the group. Applying the Fiat-Shamir transform on the group identification scheme gives rise to ring signatures, applying it to the linkable group identification scheme gives rise to zerocoin. Our ring signatures are very small compared to other ring signature schemes and we only assume the users' secret keys to be the discrete logarithms of single group elements so the setup is quite realistic. Sim- ilarly, compared with the original zerocoin protocol we only rely on a weak cryptographic assumption and do not require a trusted setup. A third application of our Sigma protocol is an efficient proof of mem- bership of a secret committed value belonging to a public list of values. -
Incentives in Ethereum's Hybrid Casper Protocol
Incentives in Ethereum’s Hybrid Casper Protocol Vitalik Buterin∗, Daniel¨ Reijsbergeny, Stefanos Leonardosy, Georgios Piliourasy ∗Ethereum Foundation ySingapore University of Technology and Design Abstract We present an overview of hybrid Casper the Friendly Finality Gadget (FFG): a Proof-of-Stake checkpointing protocol overlaid onto Ethereum’s Proof-of-Work blockchain. We describe its core functionalities and reward scheme, and explore its properties. Our findings indicate that Casper’s implemented incentives mechanism ensures liveness, while providing safety guarantees that improve over standard Proof-of-Work protocols. Based on a minimal-impact implementation of the protocol as a smart contract on the blockchain, we discuss additional issues related to parametrisation, funding, throughput and network overhead and detect potential limitations. Index Terms Proof of Stake, Ethereum, Consensus I. INTRODUCTION In 2008, the seminal Bitcoin paper by Satoshi Nakamoto [50] introduced the blockchain as a means for an open network to extend and reach consensus about a distributed ledger of digital token transfers. The main innovation of Ethereum [16] was to use the blockchain to maintain a history of code creation and execution. As such, Ethereum functions as a global computer that executes code uploaded by users in the form of smart contracts. Like Bitcoin [31], [32], Ethereum’s block proposal mechanism is based on the concept of Proof-of-Work (PoW). In PoW, network participants utilise computational power to win the right to add blocks to the blockchain. However, the alarming global energy consumption of PoW-based blockchains has made the concept increasingly controversial [22], [45], [65]. One of the main alternatives to PoW is virtual mining or Proof-of-Stake (PoS) [1], [5], [46], [55]. -
Building Applications on the Ethereum Blockchain
Building Applications on the Ethereum Blockchain Eoin Woods Endava @eoinwoodz licensed under a Creative Commons Attribution-ShareAlike 4.0 International License 1 Agenda • Blockchain Recap • Ethereum • Application Design • Development • (Solidity – Ethereum’s Language) • Summary 3 Blockchain Recap 4 What is Blockchain? • Enabling technology of Bitcoin, Ethereum, … • Distributed database without a controlling authority • Auditable database with provable lineage • A way to collaborate with parties without direct trust • Architectural component for highly distributed Internet-scale systems 5 Architectural Characteristics of a Blockchain • P2P distributed • (Very) eventual consistency • Append only “ledger” • Computationally expensive • Cryptographic security • Limited query model (key only) (integrity & non-repudiation) • Lack of privacy (often) • Eventual consistency • low throughput scalability • Smart contracts (generally – 10s txn/sec) • Fault tolerant reliability 6 What Makes a Good Blockchain Application? • Multi-organisational • No complex query requirement • No trusted intermediary • Multiple untrusted writers • Need shared source of state • Latency insensitive (e.g. transactions, identity) • Relatively low throughput • Need for immutability (e.g. proof • Need for resiliency of existence) • Transaction interactions • Fairly small data size “If your requirements are fulfilled by today’s relational databases, you’d be insane to use a blockchain” – Gideon Greenspan 7 What is Blockchain being Used For? digital ledger that tracks and derivatives post- verifiable supply chains supply chain efficiency protects valuable assets trade processing Keybase Georgia government Identity management verified data post-trade processing records 8 Public and Permissioned Blockchains Public Permissioned Throughput Low Medium Latency High Medium # Readers High High # Writers High Low Centrally Managed No Yes Transaction Cost High “Free” Based on: Do you need a Blockchain? Karl Wüst, Arthur Gervaisy IACR Cryptology ePrint Archive, 2017, p.375. -
Algorand: Scaling Byzantine Agreements for Cryptocurrencies Yossi Gilad, Rotem Hemo, Silvio Micali, Georgios Vlachos, Nickolai Zeldovich MIT CSAIL
Algorand: Scaling Byzantine Agreements for Cryptocurrencies Yossi Gilad, Rotem Hemo, Silvio Micali, Georgios Vlachos, Nickolai Zeldovich MIT CSAIL ABSTRACT open setting: since anyone can participate, an adversary can create an arbitrary number of pseudonyms (“Sybils”) [21], Algorand is a new cryptocurrency that confirms transactions making it infeasible to rely on traditional consensus proto- with latency on the order of a minute while scaling to many cols [15] that require a fraction of honest users. users. Algorand ensures that users never have divergent views of confirmed transactions, even if some of the users Bitcoin [41] and other cryptocurrencies [23, 53] address are malicious and the network is temporarily partitioned. this problem using proof-of-work (PoW), where users must In contrast, existing cryptocurrencies allow for temporary repeatedly compute hashes to grow the blockchain, and forks and therefore require a long time, on the order of an the longest chain is considered authoritative. PoW ensures hour, to confirm transactions with high confidence. that an adversary does not gain any advantage by creating Algorand uses a new Byzantine Agreement (BA) protocol pseudonyms. However, PoW allows the possibility of forks, to reach consensus among users on the next set of trans- where two different blockchains have the same length, and actions. To scale the consensus to many users, Algorand neither one supersedes the other. Mitigating forks requires uses a novel mechanism based on Verifiable Random Func- two unfortunate sacrifices: the time to grow the chain byone tions that allows users to privately check whether they are block must be reasonably high (e.g., 10 minutes in Bitcoin), selected to participate in the BA to agree on the next set and applications must wait for several blocks in order to of transactions, and to include a proof of their selection in ensure their transaction remains on the authoritative chain their network messages. -
Blockchain Consensus: an Analysis of Proof-Of-Work and Its Applications. Amitai Porat1, Avneesh Pratap2, Parth Shah3, and Vinit Adkar4
Blockchain Consensus: An analysis of Proof-of-Work and its applications. Amitai Porat1, Avneesh Pratap2, Parth Shah3, and Vinit Adkar4 [email protected] [email protected] [email protected] [email protected] ABSTRACT Blockchain Technology, having been around since 2008, has recently taken the world by storm. Industries are beginning to implement blockchain solutions for real world services. In our project, we build a Proof of Work based Blockchain consensus protocol and evauluate how major applications can run on the underlying platform. We also explore how varying network conditions vary the outcome of consensus among nodes. Furthermore, to demonstrate some of its capabilities we created our own application built on the Ethereum blockchain platform. While Bitcoin is by and far the first major cryptocurrency, it is limited in the capabilities of its blockchain as a peer-to-peer currency exchange. Therefore, Ethereum blockchain was the right choice for application development since it caters itself specifically to building decentralized applications that seek rapid deployment and security. 1 Introduction Blockchain technology challenges traditional shared architectures which require forms of centralized governance to assure the integrity of internet applications. It is the first truly democratized, universally accessible, shared and secure asset control architecture. The first blockchain technology was founded shortly after the US financial collapse in 2008, the idea was a decentralized peer-to-peer currency transfer network that people can rely on when the traditional financial system fails. As a result, blockchain largely took off and made its way into large public interest. We chose to investigate the power of blockchain consensus algorithms, primarily Proof of Work.