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Ethereum Block Structure

Merkling In Ethereum

Merkling In Ethereum

Merkle trees are a fundamental part of what makes blockchains tick. Although it is definitely theoretically possible to make a blockchain without Merkle trees, simply by creating giant block headers that directly contain every transaction, doing so poses large scalability challenges that arguably puts the ability to trustlessly use blockchains out of the reach of all but the most powerful computers in the long term. Thanks to Merkle trees, it is possible to build Ethereum nodes that run on all computers and laptops large and small, smart phones, and even internet of things devices such as those that will be produced by Slock.it . So how exactly do these Merkle trees work, and what value do they provide, both now and in the future? First, the basics. A Merkle tree, in the most general sense, is a way of hashing a large number of chunks of data together which relies on splitting the chunks into buckets, where each bucket contains only a few chunks, then taking the hash of each bucket and repeating the same process, continuing to do so until the total number of hashes remaining becomes only one: the root hash. The most common and simple form of Merkle tree is the binary Mekle tree, where a bucket always consists of two adjacent chunks or hashes; it can be depicted as follows: So what is the benefit of this strange kind of hashing algorithm? Why not just concatenate all the chunks together into a single big chunk and use a regular hashing algorithm on that? The answer is that it allows for a neat mechanism known as Merkle proofs: A Merkle proof consists of a chunk, the root hash of the tree, and the branch consisting of all of the hashes going up along the path from the chunk to the root. Someone reading the proof can verify that the hashing, at least for that branch, is c Continue reading >>

What Are Ethereum Nodes And Sharding?

What Are Ethereum Nodes And Sharding?

Angel Investors, Startups & Blockchain developers... In this guide, you will learnWhat are Ethereum Nodes And Sharding? If you have been active in one form or another in cryptocurrency for the last 1 year then you would know that there has been one issue which has plagued both bitcoin and Ethereum: Scalability. Bitcoin has somewhat addressed this issue by activating Segwit and by hard forking into Bitcoin Cash . Ethereum, however, is trying to solve this issue in a different way. One of the many protocols that they are looking to activate, as they go into the next phase of their growth, is sharding. Before we understand what that means, we need to have a thorough understanding of networks and nodes. What are nodes, networks, and parameters? Lets understand what the concept means by using simple day-to-day activities. (Before we begin, credit to 3dBuzz for the wonderful explanation.) This box takes in inputs, performs some sort of operations on them, and then gives an output. This box is a node. Keep in mind, nodes are not exactly boxes, we are just using a hypothetical case here. A network is a collection of these nodes which are interlinked to one another. Parameters are the rules that the nodes are bound by. That, in essence, is what nodes and networks are. Now lets check out some simple day-to-day activities explained via nodes and networks. Lets see how a simple paper shredder works. You are using three nodes: The paper the shredder and the.well shredded stuff. These three nodes make up the Shredding network. Lets have some more fun with this. Till now, we have assumed that nodes take in only one input. What if they take more than that? Lets take the example of a toaster. A toaster takes in two inputs: Remember one thing, a toaster cant work if even one of its inpu Continue reading >>

From Bitcoin To Ethereum

From Bitcoin To Ethereum

In response to: Cryptocurrencies and Blockchains (Vol. 2, No. 4). Jean-Paul Delahaye explains clearly in his article how the bitcoin protocol works, as well as the enthusiasm and fear it elicits. The major innovation behind bitcoin is the creation of an ecosystem that allows for a decentralized consensus. Users no longer need a reliable central authority to interact with each other. While it is difficult to predict how blockchain technology will become important in our everyday activities over the next few yearsincreasing our happiness, or notthe enthusiasm it elicits is growing. It could have many applications, of which cryptocurrencies are only an initial example. Among the platforms arousing great interest is Ethereum, which allows users to manage and interact with smart-contracts. Ethereum promises applications that work exactly as they were programmed and cannot be interrupted, censored, or modified in any way. It has been spoken of as one of the building blocks of web 3.0! Understanding precisely how all this works in practice is a fascinating subject. How can a user, interacting with the network via only his smartphone, quickly verify that a transaction has been saved on the blockchain? One approach uses the concept of a Merkle tree. This is an important data structure used in computing and cryptography, and I would like to follow up Delahayes article by explaining this point. Another legitimate question that one might ask with reference to the mechanism of transaction validation is: why do bitcoins have real economic value? There is more to bitcoin than simply a currency of exchange. To illustrate this, I will examine in some detail a transaction inscribed in the bitcoin blockchain. This has nothing to do with any financial transaction, on the contrary, it is c Continue reading >>

White Paper Ethereum/wiki Wiki Github

White Paper Ethereum/wiki Wiki Github

Introduction to Bitcoin and Existing Concepts The concept of decentralized digital currency, as well as alternative applications like property registries, has been around for decades. The anonymous e-cash protocols of the 1980s and the 1990s were mostly reliant on a cryptographic primitive known as Chaumian Blinding. [8] Chaumian Blinding provided these new currencies with high degrees of privacy, but their underlying protocols largely failed to gain traction because of their reliance on a centralized intermediary. In 1998, Wei Dai's b-money [9] became the first proposal to introduce the idea of creating money through solving computational puzzles as well as decentralized consensus, but the proposal was scant on details as to how decentralized consensus could actually be implemented. In 2005, Hal Finney introduced a concept of reusable proofs of work, [10] a system which uses ideas from b-money together with Adam Back's computationally difficult Hashcash [11] puzzles to create a concept for a cryptocurrency, but once again fell short of the ideal by relying on trusted computing as a backend. In 2009, a decentralized currency was for the first time implemented in practice by Satoshi Nakamoto, [1c] [1d] combining established primitives for managing ownership through public key cryptography with a consensus algorithm for keeping track of who owns coins, known as "proof of work." The mechanism behind proof of work was a breakthrough because it simultaneously solved two problems. First, it provided a simple and moderately effective consensus algorithm, allowing nodes in the network to collectively agree on a set of updates to the state of the Bitcoin ledger. Second, it provided a mechanism for allowing free entry into the consensus process, solving the political problem of Continue reading >>

From What Is Blockchain? To Building A Blockchain In Less Than Anhour

From What Is Blockchain? To Building A Blockchain In Less Than Anhour

Investor, writer, and emerging tech enthusiast | www.lstephanian.com From What is Blockchain? to building a blockchain in less than anhour A blockchain is a digital ledger of records thats arranged in chunks of data called blocks. These blocks then link with one another through a cryptographic validation known as a hashing function . Linked together, these blocks form an unbroken chain a blockchain. The reason that this type of data structure is useful for things like cryptocurrencies is decentralization, meaning the records inside this chain arent stored in any single location, are accessible by everyone, and are immutable by any one party. Centralized Structure Vs. Decentralized Structure, Source: SoftwareAdvice Although blockchain is most commonly associated with Bitcoin, there are many uses for this technology. There are several broad categories of blockchain applications, a couple of which include: The Blockchain that makes up Bitcoin sends money globally to individuals and merchants. But Blockchains can also create digital assets like stocks and bonds. A Blockchain can create a verifiable record of any data, file, or contract. This can be useful in any industry that uses big data, like the medical industry or government. Before you begin, I should note that this article assumes you have a basic understanding of programming and some understanding of computer science theory. This article isnt meant to be all-encompassing, but rather to serve as an introduction to blockchain programming for those looking to expand their technical knowledge. I believe that the best way to truly understand a concept is to put it into practice. If you are interested in learning how to implement a blockchain contract, Ive put together an easy-to-follow, step-by-step tutorial below. You Continue reading >>

Design Rationale Ethereum/wiki Wiki Github

Design Rationale Ethereum/wiki Wiki Github

(Image from ) Ethereum jettisons this scheme in favor of a simpler approach: the state stores a list of accounts where each account has a balance, as well as Ethereum-specific data (code and internal storage), and a transaction is valid if the sending account has enough balance to pay for it, in which case the sending account is debited and the receiving account is credited with the value. If the receiving account has code, the code runs, and internal storage may also be changed, or the code may even create additional messages to other accounts which lead to further debits and credits. Higher degree of privacy: if a user uses a new address for each transaction that they receive then it will often be difficult to link accounts to each other. This applies greatly to currency, but less to arbitrary dapps, as arbitrary dapps often necessarily involve keeping track of complex bundled state of users and there may not exist such an easy user state partitioning scheme as in currency. Potential scalability paradigms: UTXOs are more theoretically compatible with certain kinds of scalability paradigms, as we can rely on only the owner of some coins maintaining a Merkle proof of ownership, and even if everyone including the owner decides to forget that data then only the owner is harmed. In an account paradigm, everyone losing the portion of a Merkle tree corresponding to an account would make it impossible to process messages that affect that account at all in any way, including sending to it. However, non-UTXO-dependent scalability paradigms do exist. Large space savings: for example, if an account has 5 UTXO, then switching from a UTXO model to an account model would reduce the space requirements from (20 + 32 + 8) * 5 = 300 bytes (20 for the address, 32 for the txid and 8 for Continue reading >>

Blockchain - Ethereum Block Architecture - Ethereum Stack Exchange

Blockchain - Ethereum Block Architecture - Ethereum Stack Exchange

Where can I find a description (preferably a diagram like below) showing the block structure in an Ethereum blockchain? Lets first start with my adaptation adaptation of this figure illustrating the Bitcoin block structure: Enter Ethereum and things get a wee bit more complex. After reading through this and this , and as per @ eth 's recommendation this , my best interpretation is the figure below: The header field definitions are available in section 4.3 of the yellow paper . Uncles is a hash (of a list of uncles), Yellow Paper has: "The Keccak 256-bit hash of the ommers list portion of this block". Codehash is just a hash since contracts are immutable. The pointers point to "hash of whole block header" (the Keccak-256 hash of all the bytes in the block header). To have a full diagram, should really consult the Yellow Paper... eth Jan 29 '16 at 22:53 Updated response after consulting the YP. Starting to get clearer now. Thanks! zanzu Feb 1 '16 at 12:34 Why are the transactions from block N linked to those of block N+1? Sebi Jun 10 '16 at 8:31 These links correspond to contract state that has not changed in between blocks. Referencing the state from the previous blocks instead of replicating is more efficient from a block size perspective. zanzu Jun 10 '16 at 9:49 Continue reading >>

Ethereum Or Hyperledger Fabric?

Ethereum Or Hyperledger Fabric?

The sole purpose of the article is to analyse the key differences between Distributed Ledger Technologies (DLT) namely Ethereum, and Hyperledger Fabric. Both the frameworks are suited for very different visions in regard with their fields of application. Hyperledger Fabric provides customisable and extendable architecture that may be used in diverse fields ranging from banking to supply chain to healthcare et al. Ethereums unique feature of providing us with a cross-disciplinary platform for all kinds of transactions and use cases. Theoretical knowledge the following with respect to Ethereum and Hyperledger Fabric: Participation of Peers/Nodes in the decentralised network 3. Block structure (data model) in blockchain for Ethereum and Hyperledger Fabric Participation of peers/nodes depends on two modes of operation in the network: Permissionless: Anybody is allowed to participate in the network. This mode is true for Ethereum because it is a public blockchain. Permissioned: Participants are selected beforehand and only the selected participants have access to the network. This is true for Hyperledger Fabric because it is a private blockchain. Participating in the network means that entities (nodes) that participate in decentralised ledger management are permitted to contribute to it. Since every node has a copy of ledger in a blockchain, it matters how everyone decides upon a common truth. Hence, to decide upon that common truth, participation of nodes in the network becomes mandatory. The result of arriving at a common consensus happens by engaging with various algorithms like Proof of Work (PoW), or Byzantine Fault Tolerant (BFT). All peers taking part in the network have to reach consensus so that the transaction can be appended to the blockchain. Peer has to take pa Continue reading >>

How Ethereum Works - Coindesk

How Ethereum Works - Coindesk

CoinDesk Launches 2017 Year in Review Opinion and Analysis Series Now that we've covered what ethereum is, let's dive deeper into how the platform functions under the hood. Consider the online notebook application described in " What is Ethereum? " Using ethereum, the appdoesn't require one entityto store and control its data. To accomplish this, ethereum borrows heavily from bitcoin's protocol and its blockchain design, but tweaks it to support applications beyond money. Ethereum aims to abstract away bitcoin's design, however, so that developers can create applications or agreements that have additional steps, new rules of ownership, alternative transaction formats or different ways to transfer state. The goal of ethereum's 'Turing-complete' programming language is to allow developers to write more programs in which blockchain transactions could govern and automate specific outcomes. This flexibility is perhaps ethereum's primary innovation, as explained in the guide " How Ethereum Smart Contracts Work ". The structure of the ethereum blockchain is very similar to bitcoin's, in that it is a shared record of the entire transaction history. Every node on the network stores a copy of this history. The big difference withethereum is that its nodes store the most recent state of each smart contract, in addition to all of the ether transactions. (This is much more complicated than described, but the text below should help you get your feet wet.) For each ethereum application, the network needs to keep track of the 'state', or the current information of all of these applications, including each user's balance, all the smart contract code and where it's all stored. Bitcoin uses unspent transaction outputs to track who has how muchbitcoin. While it sounds more complex, the id Continue reading >>

Analysis Of Data Structures On The Ethereum Blockchain/current Draft

Analysis Of Data Structures On The Ethereum Blockchain/current Draft

Analysis of Data Structures on the Ethereum Blockchain/Current draft A smart, connected toaster is of no value unless it produces better toast. The Scenario Overview in chapter 1 demonstrates the many envisioned use-cases for the blockchain. Ethereum is in rapid development and is planning on releasing four major versions within the next year, with the last version changing the fundamental consensus algorithm. What these upgrades will change the platform in detail, is uncertain. Hence will this thesis assume the Ethereum platform as it stands at the time of writing, and will avoid too much speculating on coming changes. The scenario selected is consequently a scenario which has a short time to market and could use todays version of Ethereum. published the idea of using the blockchain for the IoT in the . The corresponding scenario examines the idea of a smart IoT washing machine [1] . The report states that the motivation behind IoT has to be creating better products for the end-user. It is argued that better products can be achieved through new digital economies and creating collaborative value, and that these elements can be achieved with P2P, trustless communication and decentralized autonomy [p.8]. These three underlying technologies will be examined in chapter 3. caption Illustration of the IBM ADEPT washers operations Pureswaran et al. explains new digital economies this way: The IoT creates the ability to digitize, sell and deliver physical assets as easily as with virtual goods today. [...] In a device driven democracy, conference rooms, hotel rooms, cars and warehouse bays can themselves report capacity, utilization and availability in real-time. [p.13] Pureswaran et al. further claims that By reducing transaction and marketing costs, and enabling partnerships Continue reading >>

Ethereum - Wikipedia

Ethereum - Wikipedia

This article has multiple issues. Please help improve it or discuss these issues on the talk page . This article relies too much on references to primary sources . Please improve this by adding secondary or tertiary sources . Some of this article's listed sources may not be reliable . Please help this article by looking for better, more reliable sources. Unreliable citations may be challenged or deleted. The Ethereum Project's logo, first used in 2014 Ethereum is an open-source , public, blockchain -based distributed computing platform featuring smart contract (scripting) functionality. [2] It provides a decentralized Turing-complete virtual machine , the Ethereum Virtual Machine (EVM), which can execute scripts using an international network of public nodes. Ethereum also provides a cryptocurrency token called "ether", which can be transferred between accounts and used to compensate participant nodes for computations performed. [3] "Gas", an internal transaction pricing mechanism, is used to mitigate spam and allocate resources on the network. [2] [4] Ethereum was proposed in late 2013 by Vitalik Buterin , a cryptocurrency researcher and programmer. Development was funded by an online crowdsale between July and August 2014. [5] The system went live on 30 July 2015, with 11.9 million coins "premined" for the crowdsale. [6] This accounts for approximately 13 percent of the total circulating supply. In 2016, as a result of the collapse of The DAO project, Ethereum was forked into two separate blockchains - the new forked version became Ethereum (ETH), and the original continued as Ethereum Classic (ETC). [7] [8] [9] Ethereum was initially described in a white paper by Vitalik Buterin , [10] a programmer involved with Bitcoin Magazine , in late 2013 with a goal of buildin Continue reading >>

A Gentle Introduction To Ethereum

A Gentle Introduction To Ethereum

Ethereum builds on blockchain and cryptocurrency concepts, so if you are not familiar with these, its worth reading a gentle introduction to bitcoin and a gentle introduction to blockchain technology first. This article assumes the reader has a basic familiarity with how Bitcoin works. Ethereum is software running on a network of computers that ensures that data and small computer programs called smart contracts are replicated and processed on all the computers on the network, without a central coordinator. The vision is to create an unstoppable censorship-resistant self-sustaining decentralised world computer. The officialwebsite is Itextends the blockchain concepts from Bitcoin which validates, stores, and replicates transaction data on many computers around the world (hence the term distributed ledger). Ethereum takes this one step further, and also runs computer code equivalently on many computers around the world. What Bitcoin does for distributed data storage, Ethereum does for distributed data storage plus computations. The small computer programsbeing run are called smart contracts, and the contractsare run by participants on their machines using asort ofoperating system called a Ethereum Virtual Machine. To run Ethereum, you can download (or write yourself if you have the patience) some software called an Ethereum client. Just like BitTorrent or Bitcoin, the Ethereum client will connect over the internet to other peoples computers running similar client softwareand start downloading the Ethereum blockchain from them to catch up. It will also independently validate that each block conforms to the Ethereum rules. What does the Ethereum client software do? You can use itto: Create new transactions and smart contracts Your computer becomes a node on the network, r Continue reading >>

Blockchain Tests Ethereum Homestead 0.1 Documentation

Blockchain Tests Ethereum Homestead 0.1 Documentation

The 160-bit address to which all fees collected from the successful mining of this block betransferred, as returned by the COINBASE instruction. A scalar value corresponding to the difficulty level of this block. This can be alculatedfrom the previous blocks difficulty level and the timestamp, as returned by the DIFFICULTY instruction. A scalar value equal to the current limit of gas expenditure per block, as returned by the GASLIMIT instruction. A scalar value equal to the number of ancestor blocks. The genesis block has a number of zero. A scalar value equal to the reasonable output of Unixs time() at this blocks inception, as returned by the TIMESTAMP instruction. The Keccak 256-bit hash of the parent blocks header, in its entirety The Bloom filter composed from indexable information (logger address and log topics)contained in each log entry from the receipt of each transaction in the transactions list. An arbitrary byte array containing data relevant to this block. This must be 1024 bytes or fewer. A scalar value equal to the total gas used in transactions in this block. A 256-bit hash which proves that a sufficient amount of computation has been carried out on this block. The Keccak 256-bit hash of the root node of the trie structure populated with the receipts of each transaction in the transactions list portion of the block. The Keccak 256-bit hash of the root node of the state trie, after all transactions are executed and finalisations applied. The Keccak 256-bit hash of the root node of the trie structure populated with each transaction in the transactions list portion of the block. The Keccak 256-bit hash of the uncles list portion of this block pre section: as described in State Tests. postState section: as described in State Tests (section - post). blocks s Continue reading >>

An Introduction To Ethereum And Smart Contracts: A Programmable Blockchain

An Introduction To Ethereum And Smart Contracts: A Programmable Blockchain

An Introduction to Ethereum and Smart Contracts: a Programmable Blockchain Bitcoin took the world by surprise in the year 2009 and popularized the idea of decentralized secure monetary transactions. The concepts behind it, however, can be extended to much more than just digital currencies. Ethereum attempts to do that, marrying the power of decentralized transactions with a Turing-complete contract system. In this post we will take a closer look at how Ethereum works and what makes it different from Bitcoin and other blockchains. Read on! In our previous post , we took a closer look at what blockchains are and how they help in making distributed, verifiable transactions a possibility. Our main example was Bitcoin: the world's most popular cryptocurrency. Millions of dollars, in the form of bitcoins, are traded each day, making Bitcoin one of the most prominent examples of the viability of the blockchain concept. Have you ever found yourself asking this question: "what would happen if the provider of this service or application disappeared?" If you have, then learning about Ethereum can make a big difference for you. Ethereum is a platform to run decentralized applications: applications that do not rely on any central server. In this post we will explore how Ethereum works and build a simple PoC application related to authentication. A blockchain is a distributed, verifiable datastore. It works by marrying public-key cryptography with the nobel concept of the proof-of-work. Each transaction in the blockchain is signed by the rightful owner of the resource being traded in the transaction. When new coins (resources) are created they are assigned to an owner. This owner, in turn, can prepare new transactions that send those coins to others by simply embedding the new owner Continue reading >>

Introduction To Smart Contracts

Introduction To Smart Contracts

Let us begin with the most basic example. It is fine if you do not understand everythingright now, we will go into more detail later. pragma solidity ^0.4.0;contract SimpleStorage { uint storedData; function set(uint x) public { storedData = x; } function get() public constant returns (uint) { return storedData; }} The first line simply tells that the source code is written forSolidity version 0.4.0 or anything newer that does not break functionality(up to, but not including, version 0.5.0). This is to ensure that thecontract does not suddenly behave differently with a new compiler version. The keyword pragma is called that way because, in general,pragmas are instructions for the compiler about how to treat thesource code (e.g. pragma once ). A contract in the sense of Solidity is a collection of code (its functions) anddata (its state) that resides at a specific address on the Ethereumblockchain. The line uint storedData; declares a state variable called storedData oftype uint (unsigned integer of 256 bits). You can think of it as a single slotin a database that can be queried and altered by calling functions of thecode that manages the database. In the case of Ethereum, this is always the owningcontract. And in this case, the functions set and get can be used to modifyor retrieve the value of the variable. To access a state variable, you do not need the prefix this. as is common inother languages. This contract does not do much yet (due to the infrastructurebuilt by Ethereum) apart from allowing anyone to store a single number that is accessible byanyone in the world without a (feasible) way to prevent you from publishingthis number. Of course, anyone could just call set again with a different valueand overwrite your number, but the number will still be stored in the Continue reading >>

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