blockchain

Best practice to save files in blockchain

由 扶醉桌前 提交于 2019-11-29 10:28:49
问题 What is the best practice to save files as part of a blockchain's data? I have tremendously large files to be saved. Can't we save these file on cloud storage (centralized solution like dropbox), and link them with blockchain data using a file hash? Or is it better to use a distributed file storage like IPFS? Or is there any better solution in term of security, volume, performance, and fault tolerance. 回答1: You do not want to directly use a traditional blockchain. Blockchains are good for

Where do smart contracts reside in blockchain (Ethereum or Hyperledger)

由 China☆狼群 提交于 2019-11-28 22:17:40
问题 So, let us consider a typical trade finance process flow. Exporter deploys a contract that has conditions of the shipment and a hash is generated once the deployment is finished. Questions: 1) Where is the contract stored? 2) How other participants such as customs and importer can access this contract? 3) Can we activate participant level access to the contract on the blockchain? 回答1: There are several aspects to Ethereum and Hyperledger which make them quite different. Let me give a somewhat

Fabric composer integration with Bluemix blockchain service

由 浪尽此生 提交于 2019-11-28 08:50:55
Can a composer fabric business network, .bna file, be deployed to the bluemix blockchain service today? If so, is there a connection profile example that someone can share? Thanks. You can use Composer with the Bluemix Blockchain service today. However, you must be running a local copy of the Composer Playground as the version of Composer running on Bluemix (fabric-composer.mybluemix.net) only supports the web connection profile at the moment. You can set up a local copy of the Composer Playground by following the instructions here: https://fabric-composer.github.io/start/getting-started

Are blocks mined in HyperLedger Fabric?

由 橙三吉。 提交于 2019-11-28 05:07:05
I have been reading the documentation on how HyperLedger Fabric's project is implementing a open source BlockChain solution: https://github.com/hyperledger/fabric/blob/master/docs/protocol-spec.md I have seen that PBFT consensus algorithm is used, but I do not understand how blocks are mined and shared among all Validating Peers in the BlockChain network. Hyperledger Validating Peers (VPs) do not mine blocks and do not share the blocks between them. Here is how it works: A transaction is send to one trusted VP. The VP broadcasts the transaction to all other VPs. All VPs reach consensus (using

Hyperledger Fabric GOSSIP_BOOTSTRAP & GOSSIP_EXTERNALENDPOINTS

由 …衆ロ難τιáo~ 提交于 2019-11-27 15:16:47
问题 I was looking into the docker configuration files and found two parameters in peer environment as shown below: environment: - CORE_PEER_ID=peer0.org1.example.com - CORE_PEER_ADDRESS=peer0.org1.example.com:7051 - CORE_PEER_GOSSIP_BOOTSTRAP=peer1.org1.example.com:7051 - CORE_PEER_GOSSIP_EXTERNALENDPOINT=peer0.org1.example.com:7051 - CORE_PEER_LOCALMSPID=Org1MSP Can anyone explain what there two variables CORE_PEER_GOSSIP_BOOTSTRAP & CORE_PEER_GOSSIP_EXTERNALENDPOINT works. How they can be

Fabric composer integration with Bluemix blockchain service

由 守給你的承諾、 提交于 2019-11-27 02:28:23
问题 Can a composer fabric business network, .bna file, be deployed to the bluemix blockchain service today? If so, is there a connection profile example that someone can share? Thanks. 回答1: You can use Composer with the Bluemix Blockchain service today. However, you must be running a local copy of the Composer Playground as the version of Composer running on Bluemix (fabric-composer.mybluemix.net) only supports the web connection profile at the moment. You can set up a local copy of the Composer

Are blocks mined in HyperLedger Fabric?

由 风流意气都作罢 提交于 2019-11-27 00:48:09
问题 I have been reading the documentation on how HyperLedger Fabric's project is implementing a open source BlockChain solution: https://github.com/hyperledger/fabric/blob/master/docs/protocol-spec.md I have seen that PBFT consensus algorithm is used, but I do not understand how blocks are mined and shared among all Validating Peers in the BlockChain network. 回答1: Hyperledger Validating Peers (VPs) do not mine blocks and do not share the blocks between them. Here is how it works: A transaction is

Send ERC20 token with web3

由 喜欢而已 提交于 2019-11-26 20:50:28
I'm currently using 0.2x.x version of Web3 Javascript API. I deployed my custom ERC20 token by creating smart contract in solidity (on REMIX IDE). I installed the MetaMask and had a test on https://wallet.ethereum.org/ to send some custom ERC token to another my account. It worked well. I want to add the 'send custom ERC20 Token' function in my javascript code using Web3. Here is my code below. var http = require('http'); var Web3 = require('web3'); var Tx = require('ethereumjs-tx'); var abi = [{"...."}]; var data = '0x00..'; var contract_addr = '0x00..'; var owner = '0x00..'; var web3 = new
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