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Proof Of Stake_ethereum.pdf - Proof Of Stake Faq...

Proof Of Stake_ethereum.pdf - Proof Of Stake Faq...

Proof of Stake_ethereum.pdf - Proof of Stake FAQ... 7/22/2017Proof of Stake FAQ ethereum/wiki Wiki GitHubWhitepaperDesign RationaleEthereum Yellow PaperFAQEthereum Clientscpp-ethereum (C++)ethereumj (Java)Geth (Go)Parity (Rust)pyethapp (Python)App DevelopmentSafetyApp Developer ResourcesJavaScript APIJSON RPC APISoliditySolidity FeaturesSolidity CollectionsUseful app PatternsStandardized Contract APIsApp using MeteorEthereum development tutorialMix TutorialMix FeaturesViperSerpentLLLMutanInfrastructureChain Spec FormatInter-exchange Client AddressProtocolURL Hint ProtocolNatSpec DeterminationNetwork StatusRaspberry PiExchange IntegrationProof of Stake FAQvbuterin edited this page 12 days ago 46 revisionsWhat is Proof of StakeProof of stake is a category of consensus algorithms for public blockchains, which Ethereum'supcoming Casper algorithm is a part of. It serves a similar function to the proof of work whichunderpins the security behind Bitcoin, the current version of Ethereum and many otherblockchains, but has significant advantages in terms of security and energy efficiency.In general, a proof of stake algorithm looks as follows. The blockchain keeps track of a set ofvalidators, and anyone who holds the blockchain's base cryptocurrency (in Ethereum's case, ether)can become a validator by sending a special type of transaction that locks up their ether into adeposit. The process of creating and agreeing to new blocks is then done through a consensusalgorithmthat all current validators can participate in.There are many kinds of consensus algorithms, and many ways to assign rewards to validators whoparticipate in the consensus algorithm, so there are many "flavors" of proof of stake. From analgorithmic perspective, there are two major types: chain-based proof of stakea Continue reading >>

Ethereum/ethereumj - Gitter

Ethereum/ethereumj - Gitter

Java implementation of the Ethereum protocol I would like to join EthereumJ Project as contributor to learn more about Ethereum , writing java code, french or english documentation or tutorial , building EthereumJ docker .... How can i do to join the project EthereumJ as contributor. ( i'm java developer) Checkout the source, make contributions and send in a pull-request havent looked yet, but is PoS being implemented or planned ? I am looking into Proof-of-Authority re: Gavin's work in cppEth Casper is being developed. There is a difficulty bomb, so some incentive to keep working on it Thanks @nicksavers - would like to bounce off my PoA algo - writing it up at the moment.. Is it possible to get all transactions for address? I'm looking for it in RepositoryTrack, but can't find anything similar @cazanlekor_twitter Sure you are welcome to contribute! Just clone the repo, pick up any github issue, and make a pull request with the fix @a7ex12 Nope, we don't maintain such DB inside the core lib. You need to track all the transactions and collect this info by yourself Hi ! Need a quick help .. I was syncing for the past two days and suddenly got this error :[ 00:29:04.748 INFO [blockqueue] Success importing BEST: block.number: 1149149, block.hash: c3091b, tx.size: 5 00:29:04.821 ERROR [blockchain] Block's given Receipt Hash doesn't match: 927e20837679eece7160879210a3634d7446c4d52a5689ff47da345c213b8351 != a8396f1859a16d84e386d1536edffee5829891ce5bf633a8511f06bb9ba6776a00:29:04.823 ERROR [state] BLOCK: STATE CONFLICT! block: 1149150 worldstate 2e0e488cb7b49e319e0941b75a9a2bf5a9a767b92a17e6c1ba86e1f34714c651 mismatch00:29:04.824 ERROR [state] Conflict block dump: f905caf90219a0c3091b4857e93211651f798df7f41ed1a77d56b8f3ef5904cb2a8a8ee7e58f46a05d06bdea930da3e8e14e8769506c733bd Continue reading >>

How To Send Ethereum Transactions With Java

How To Send Ethereum Transactions With Java

After Ive expressed my concerns about the blockchain technology , lets get a bit more practical with the blockchain. In particular, with Ethereum. I needed to send a transaction with Java, so I looked at EthereumJ . You have three options: Full node you enable syncing, which means the whole blockchain gets downloaded. It takes a lot of time, so I abandoned that approach Light node you disable syncing, so you just become part of the network, but dont fetch any parts of the chain. Not entirely sure, but I think this corresponds to the light mode of geth (the ethereum CLI). You are able to send messages (e.g. transaction messages) to other peers to process and store on the blockchain, but you yourself do not have the blockchain. Offline (no node) just create and sign the transaction, compute its raw representation (in the ethereum RLP format) and push it to the blockchain via a centralized API, e.g. the etherscan.io API . Etherscan is itself a node on the network and it can perform all of the operations (so it serves as a proxy) Before going further, maybe its worth pointing out a few general properties of the blockchain (the ethereum one and popular cryptocurrencies at least) it is a distributed database, relying on a peer-to-peer (overlay) network, formed by whoever has a client software running (wallet or otherwise). Transactions are in the form of I (private key owner) want to send this amount to that address. Transactions can have additional data stored inside them, e.g. representing what they are about. Transactions then get verified by peers (currently using a Proof-of-work based consensus) and get stored on the blockchain, which means every connected peer gets the newly created blocks (each block consisting of multiple transactions). Thats the blockchain in short, Continue reading >>

Introduction To Ethereumj

Introduction To Ethereumj

If you're new here, you may want to check out the "API Discoverability with Spring and Spring HATEOAS" live Webinar . Thanks for visiting! I just announced the new Spring 5 modules in REST With Spring: In this article, we take a look at the EthereumJ library that allows us to interact with the Ethereum blockchain, using Java. First, lets just briefly dive into what this technology is all about. Ethereum is acryptocurrencyleveraging a distributed, peer-to-peer, database in the form of a programmableblockchain, the Ethereum Virtual Machine (EVM). Its synchronized and operated through disparate but connectednodes. As of 2017, Nodessynchronize theblockchainthrough consensus, create coins through mining (proof of work), verify transactions, executesmart contracts written in Solidity , and run the EVM. The blockchainis divided intoblockswhich containaccount states(including transactions betweenaccounts) andproof of work. The org.ethereum.facade.Ethereumclass abstracts and unites many packages of EthereumJ into one easy to use interface. Its possible to connect to a node to sync with the overall network and, once connected, we can work with the blockchain. Ethereum ethereum = EthereumFactory.createEthereum(); To connect to the network, we must first connect to a node, i.e.a server running the official client. Nodesare represented by theorg.ethereum.net.rlpx.Node class. The org.ethereum.listener.EthereumListenerAdapter handles blockchain events detected by our client after connection to a nodehas been established successfully. Lets connect to a node on the network. This can be done manually: String ip = "port = 8345;String nodeId = "a4de274d3a159e10c2c9a68c326511236381b84c9ec...";ethereum.connect(ip, port, nodeId); Connecting to the network can also be done automatically using Continue reading >>

Github - Ethereum/ethereumj: Java Implementation Of The Ethereum Yellowpaper. For Json-rpc And Other Client Features Check Ethereum Harmony

Github - Ethereum/ethereumj: Java Implementation Of The Ethereum Yellowpaper. For Json-rpc And Other Client Features Check Ethereum Harmony

Java implementation of the Ethereum yellowpaper. For JSON-RPC and other client features check Ethereum Harmony If nothing happens, download GitHub Desktop and try again. If nothing happens, download GitHub Desktop and try again. If nothing happens, download Xcode and try again. If nothing happens, download the GitHub extension for Visual Studio and try again. EthereumJ is a pure-Java implementation of the Ethereum protocol. For high-level information about Ethereum and its goals, visit ethereum.org . The ethereum white paper provides a complete conceptual overview, and the yellow paper provides a formal definition of the protocol. We keep EthereumJ as thin as possible. For JSON-RPC support and other client features check Ethereum Harmony . Adding as a dependency to your Maven project: org.ethereum ethereumj-core 1.6.3-RELEASE repositories { mavenCentral() jcenter() maven { url "} } compile "org.ethereum:ethereumj-core:1.6.+" As a starting point for your own project take a look at git clone ethereumjcp ethereumj-core/src/main/resources/ethereumj.conf ethereumj-core/src/main/resources/user.confvim ethereumj-core/src/main/resources/user.conf # adjust user.conf to your needs./gradlew clean shadowJarjava -jar ethereumj-core/build/libs/ethereumj-core-*-all.jar > git clone cd ethereumj> ./gradlew run [-PmainClass=] ./gradlew run -PmainClass=org.ethereum.samples.BasicSample./gradlew run -PmainClass=org.ethereum.samples.FollowAccount./gradlew run -PmainClass=org.ethereum.samples.PendingStateSample./gradlew run -PmainClass=org.ethereum.samples.PriceFeedSample./gradlew run -PmainClass=org.ethereum.samples.PrivateMinerSample./gradlew run -PmainClass=org.ethereum.samples.TestNetSample./gradlew run -Pmain Continue reading >>

Interfacing With Ethereum Smart Contracts Injava

Interfacing With Ethereum Smart Contracts Injava

Interfacing with Ethereum Smart Contracts inJava Since quite a lot of business applications are written in Java, or make use of the JVM for that matter, I believe a primer on how to interface with an Ethereum Smart Contract in Java will prove helpful to the reader. This post requires knowledge of what a Smart Contract is and how to deploy one. To learn why we will probably use a library for interfacing with the Smart Contract a basic understanding of the usage of JSON-RPC in Ethereum is necessary. Lets unveil the supposed magic behind what almost all Ethereum libraries do to interact with the blockchain. Suppose we need to know the gasLimit (maximum amount of computational effort the transactions in a block are allowed to have) of the latest block. Using curl and piping its result to a JSON parser such as jq would, considering we run an Ethereum node on localhost port 8545, look as follows curl --silent -X POST -H "Content-Type: application/json"\ --data '{"jsonrpc":"2.0","method":"eth_getBlockByNumber","params":["latest", true],"id":1}' localhost:8545 | jq .result.gasLimit The above will yield 0x4c4b3c, which is hex-encoded . Since we probably want to read it as a decimal we can add another pipe and the final command becomes curl --silent -X POST -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"eth_getBlockByNumber","params":["latest", true],"id":1}' localhost:8545\ Leading to the readable result of 4999996. These steps involved are a good showcase on why to introduce an abstraction. Almost all libraries will provide convenient interfaces for these RPC calls. Using the library web3j the command above will translate to web3j.ethGetBlockByNumber(DefaultBlockParameter.valueOf("latest"), Still a lot of steps, and from a software-engineering perspecti Continue reading >>

Dapps Ethereum Classic 0.1 Documentation

Dapps Ethereum Classic 0.1 Documentation

Swarm is a distributed storage platform and content distribution service, a native base layer service of the Ethereum web 3 stack. The primary objective of Swarm is to provide a sufficiently decentralized and redundant store of Ethereums public record, in particular to store and distribute dapp code and data as well as block chain data. From an economic point of view, it allows participants to efficiently pool their storage and bandwidth resources in order to provide the aforementioned services to all participants. From the end users perspective, Swarm is not that different from WWW, except that uploads are not to a specific server. The objective is to peer-to-peer storage and serving solution that is DDOS-resistant, zero-downtime, fault-tolerant and censorship-resistant as well as self-sustaining due to a built-in incentive system which uses peer to peer accounting and allows trading resources for payment. Swarm is designed to deeply integrate with the devp2p multiprotocol network layer of Ethereum as well as with the Ethereum blockchain for domain name resolution, service payments and content availability insurance. Continue reading >>

Parity

Parity

Parity comes with an extensive, easy-to-use, in-built Ethereum Wallet and app environment that can be accessed via your Web browser of choice. Account, address book and multi-sig management Hardware and electronic cold wallet support Develop smart contracts and decentralised applications with Parity or build protocol extensions. Check out our Wiki , Gitter and Bug Bounty Program Parity is designed for mission critical use in enterprise environments. Parity has a number of features that make it perfect for deployment in private or consortium setting. The Parity Ethereum client is built from the ground up to the highest standards of software development. Tuned, hand optimised use of low-level Rust language JITEVM turbocharges execution of complex contracts Multi-level in-memory caching Memory and concurrency safety guaranteed by Rust language Actor-based modularity ensures maximal resilience Unit tested and peer reviewed from day one Standard, JSON-based, chain-specification format EVM plugins allow native speed contracts Actor-based modular architecture with IPC Rust's ownership tracking facilitates minimal memory footprint Cache management gives fine control to user State-trie pruning minimises storage footprint 1-line install on Mac and Linux Docker images available Library APIs are fully documented 100% consensus test conformant implementation Complies with standard devp2p network protocol Fully compatible with JSON-RPC API Stable is the most mature and tested software Beta comes with additional features and better performance but may yet have quirks and issues to be fixed Nightly is a cutting edge software build but comes with a strong caveat against using it for managing anything of value From RLP and the Trie to the network subsystem. We aim for our unit tests to Continue reading >>

Tutorial 3: Introduction To The Javascript Api

Tutorial 3: Introduction To The Javascript Api

We are going to take a quick look at some of the bindings in the Javascript API and how they can be used to build powerful front ends for your dapps. To start with it's important to understand that all of our functions are asynchronous and return promises. This avoids problems that arise when synchronous javascript functions block the running of other code and hold up the other functions that. If you are not familiar with promises I advise you to take a moment to read up on their use before proceeding as they can be quite confusing for the novice user. For those of you who are comfortable with promises, lets dive in. We are going to be using the below html/javascript template and we will add new javascripts function while explaining what they do. We will not be using any custom libraries and our only aesthetic choice will be to use bootstrap to make things look nice. JavaScript API ///First web3.eth.watch code to monitor coinbase ///Insert your contract address var here: ///Second web3.eth.watch code to monitor block number JavaScript API

Coinbase Address:
Balance:
Latest Block Number:
Latest Block Timestamp:
Latest Block Hash:
Contract String:
Favourite Python:
Take the above and paste it into your preferred text editor and save it as a html file somewhere convenient. Now open Alethzero and use the browser to navigate to it. You should see the below: We have listed several pieces of information; Coinbase Addre Continue reading >>

How To Send Ethereum Transactions With Java

How To Send Ethereum Transactions With Java

How to Send Ethereum Transactions With Java How to Send Ethereum Transactions With Java If you're Java developer dipping into the Ethereum blockchain, here's what you need to know about the ins and outs of sending transactions. Aug. 11, 17 Java Zone Build vs Buy a Data Quality Solution: Which is Best for You? Gain insights on a hybrid approach. Download white paper now! After Ive expressed my concerns about the blockchain technology , lets get a bit more practical with the blockchain. In particular, with Ethereum. I needed to send a transaction with Java, so I looked at EthereumJ . You have three options: Full node you enable syncing, which means the whole blockchain gets downloaded. It takes a lot of time, so I abandoned that approach Light node you disable syncing, so you just become part of the network, but dont fetch any parts of the chain. Not entirely sure, but I think this corresponds to the light mode of geth (the Ethereum CLI). You are able to send messages (e.g. transaction messages) to other peers to process and store on the blockchain, but you yourself do not have the blockchain. Offline (no node) just create and sign the transaction, compute its raw representation (in the Ethereum RLP format) and push it to the blockchain via a centralized API, e.g. the etherscan.io API . Etherscan is itself a node on the network and it can perform all of the operations (so it serves as a proxy) Before going further, maybe its worth pointing out a few general properties of the blockchain (the Ethereum one and popular cryptocurrencies at least) it is a distributed database, relying on a peer-to-peer (overlay) network, formed by whoever has a client software running (wallet or otherwise). Transactions are in the form of I (private key owner) want to send this amount to that Continue reading >>

Dapps Expanse Homestead 0.1 Documentation

Dapps Expanse Homestead 0.1 Documentation

Swarm is a distributed storage platform and content distribution service, a native base layer service of the Expanse web 3 stack. The primary objective of Swarm is to provide a sufficiently decentralized and redundant store of Expanses public record, in particular to store and distribute dapp code and data as well as block chain data. From an economic point of view, it allows participants to efficiently pool their storage and bandwidth resources in order to provide the aforementioned services to all participants. From the end users perspective, Swarm is not that different from WWW, except that uploads are not to a specific server. The objective is to peer-to-peer storage and serving solution that is DDOS-resistant, zero-downtime, fault-tolerant and censorship-resistant as well as self-sustaining due to a built-in incentive system which uses peer to peer accounting and allows trading resources for payment. Swarm is designed to deeply integrate with the devp2p multiprotocol network layer of Expanse as well as with the Expanse blockchain for domain name resolution, service payments and content availability insurance. Continue reading >>

Possible To Create Dapp Using Ethereumj?

Possible To Create Dapp Using Ethereumj?

I am familiar creating Dapps by using Web3.js , I could able to do so , even in a normal browser ( without Mist). But wondering if that is possible by using EthereumJ ? So instead of browser ( web3.js) connecting directing to the network and getting it done, the request should go through our hosted server which serves the data by using EhtereumJ ? My Intention to use spring mvc web application. What the aim of adding this server step? It removes the decentralized advantage of blockchain. Nicolas Massart May 24 '16 at 14:42 Agreed @NicolasMassart, But I am planning for a centralized system ( private blockchain) . And moreover our application is going to be a hybrid solution ( part blockchain part enterprise application ).Due to the fact that blockchain would be slow for the model I thought of. The Neo Noir Developer May 24 '16 at 14:52 so yes it's possible. Without knowing your entire project however I can't tell you if it's the best architecture. Nicolas Massart May 24 '16 at 15:43 You could probably do this, but it's unlikely to be the best approach. All three main clients expose a set of APIs via JSON-RPC; this is what web3 apps call. Instead of integrating directly with a client, you should run a stock node, and call these APIs from your webapp. I know this is a tad late but my 2 cents since I just got back around to EthereumJ.. Just some ideas for people who may stumble on this.. Java has a webview client built in, . I was working on a project similar to what you're asking about, using ethJ and webview, before the json-rpc interface was implemented. I'd explore using the webview function to display HTML interfaces with some js interacting with the core through RPC. You can expose java classes and methods to javascript but I do not know how flexible or convenient th Continue reading >>

Ethereum/ethereumj - Gitter

Ethereum/ethereumj - Gitter

Java implementation of the Ethereum protocol @Nashatyrev is there a special channel for Harmony or I can shoot my questions here ? @adridadou Shoot them here, I asked the Harmony author to join the channel I'd like to know how easy it is to configure harmony to connect to a private network If I can simply configure it then I can use it to connect to my own private network and have a view of what is going on the network ooh I haven't seen this page. Thank you ! [RomanJ, ] Harmony love you back <3 Few little things I need to work through on a private network. @romanman is there a change I need to make to see hashrate from other nodes? So, I'm on a pretty develop build from a few days ago, and it's running decently, but is pretty constantly disconnecting and reconnecting to its peers. Seeing a bunch of Peer e6850141: is a bad one, drop kind of messages without much of a hint as to why. Any ideas? I have built the latest ethereumj library using develop branch. cp ethereumj-core/src/main/resources/ethereumj.conf ethereumj-core/src/main/resources/user.conf I am using default ethereumj conf....do I need to make any changes ? @basavk default ethereumj conf must be fine, 6 nodes is good I can see database folder size as 2 MB only did you notice any errors or warns in console? 23:44:37.117 INFO [discover] Write Node statistics to DB: 6 nodes. which command did you use to launch ethereumj? java -jar ethereumj-core/build/libs/ethereumj-core-*-all.jar followed same steps as mentioned in READMe Previously, I was able to run the node like this.. (some 1 month back) without any issues will there be any firewall issue on windows ? ~11GB for live network. Syncing will take many hours due to recent attacks is there any --fastsync option available like geth ? @ewiner This is n Continue reading >>

Alexander Culum Blockchainers

Alexander Culum Blockchainers

The good thing about standards is that there are so many to choose from. Andrew S. Tanenbaum The current state of Token standards on the Ethereum platform is surprisingly simple: ERC-20 Token Standard is the only accepted and adopted (as EIP-20 ) standard for a Token interface. Proposed in 2015, it has finally been accepted at the end of 2017. In the meantime, many Ethereum Requests for Comments (ERC) have been proposed which address shortcomings of the ERC-20, which partly were caused by changes in the Ethereum platform itself, eg. the fix for the re-entrancy bug with EIP-150 . Other ERC propose enhancements to the ERC-20 Token model. These enhancements were identified by experiences gathered due to the broad adoption of the Ethereum blockchain and the ERC-20 Token standard. The actual usage of the ERC-20 Token interface resulted in new demands and requirements to address non-functional requirements like permissioning and operations. This blogpost should give a superficial, but complete, overview of all proposals for Token(-like) standards on the Ethereum platform. This comparison tries to be objective but most certainly will fail in doing so. The Mother of all Token Standards: ERC-20 There are dozens of very good and detailed description of the ERC-20, which will not be repeated here. Just the core concepts relevant for comparing the proposals are mentioned in this post. Users trying to understand the ERC-20 interface and especially the usage pattern for transfering Tokens from one externally owned account (EOA), ie. an end-user (Alice), to a smart contract, have a hard time getting the approve/transferFrom pattern right. From a software engineering perspective, this withdraw pattern is very similar to the Hollywood principle (Dont call us, well call you!). The idea Continue reading >>

Gitbrowse - Github Repo Recommendations

Gitbrowse - Github Repo Recommendations

Java implementation of the Ethereum yellowpaper XChange is a Java library providing a streamlined API for interacting with 50+ Bitcoin and Altcoin exchanges providing a consistent interface for trading and accessing market data. A RESTful API for banks that supports: accounts, transactions, counterparties, transfers (payments), entitlements (permissions), metadata on the above (comments, tags, geo tags, urls etc.), multiple v A P2P-based high performance key-value pair storage library Xuggle's Xuggler Java API for Video -- DEPRECATED Artificial Intelligence Challenge - scala game server Feature experiments to advance the art of Bitcoin (Official) The DSpace digital asset management system that powers your Institutional Repository turtles, patches, and links for kids, teachers, and scientists (current version: Osmosis is a command line Java application for processing OSM data. Xtext is a language development framework Hierarchical Temporal Memory implementation in Java - an official Community-Driven Java port of the Numenta Platform for Intelligent Computing (NuPIC). The free Java library for Asterisk PBX integration. Lighthouse: a peer to peer crowdfunding app that uses Bitcoin Embed Node.js inside a Java Virtual Machine Read-only mirror of ASF Git Repo for jclouds Neo4j Spatial is a library of utilities for Neo4j that faciliates the enabling of spatial operations on data. In particular you can add spatial indexes to already located data, and perform spatial ope Real-time collaborative editing plugin for IntelliJ Drools and jBPM integration with seam, spring, camel, ... Open MCT for the desktop is no longer under active development. Our development efforts are now focused on Open MCT for the web and for mobile devices MultiBit is a desktop bitcoin client, powered by bi Continue reading >>

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