Most viewed questions in Blockchain

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How to create users on hyperledger and how to assign policies to the created users?

First the users need to establish identity ...READ MORE

Jul 10, 2018 in Blockchain by slayer
• 29,350 points
1,612 views
0 votes
1 answer

Error while trying to create dir if missing: mkdir /var/hyperledger: permission denied

The following commands should help: sudo mkdir -p ...READ MORE

Jul 6, 2018 in Blockchain by Christine
• 15,790 points
1,605 views
0 votes
1 answer

Solidity: logical AND outputs parser error

Its Syntax error logical and operator is ...READ MORE

Oct 12, 2018 in Blockchain by Perry
• 17,100 points
1,601 views
0 votes
1 answer

What is my chaincode ID in Hyperledger Fabric?

Hey. You have used chaincode id but ...READ MORE

Nov 21, 2018 in Blockchain by Omkar
• 69,230 points
1,599 views
0 votes
1 answer

What is the difference between hashing and encryption process?

Hashing and encryption are same but not ...READ MORE

Dec 4, 2018 in Blockchain by Omkar
• 69,230 points
1,596 views
–1 vote
1 answer

Miner in Ethereum Private network is hanging

Looking at your commands again, I figured ...READ MORE

Jan 17, 2019 in Blockchain by Omkar
• 69,230 points
1,589 views
0 votes
1 answer

Send Payment error in Blockchain API

The following code should help: $address = null; try ...READ MORE

Jul 6, 2018 in Blockchain by Perry
• 17,100 points
1,586 views
0 votes
2 answers

Hyperledger sawtooth installation: No connectivity between host computer and docker container

Check the ip used by docker. If ...READ MORE

Jan 21, 2019 in Blockchain by Bhavana
1,573 views
+4 votes
2 answers

Warning: Invoking events without “emit” prefix is deprecated while truffle compile

As the warning mentions, add emit as ...READ MORE

Oct 16, 2018 in Blockchain by Aisha
1,572 views
+1 vote
0 answers

Error 500 during instantiation of chaincode for commercial-paper example. [closed]

I am following this tutorial on setting ...READ MORE

Jan 9, 2020 in Blockchain by Aditya
• 250 points

reshown Jan 9, 2020 by Kalgi 1,568 views
0 votes
1 answer

Accessing External Api in HyperLedger Fabric

Generally you are not supposed to call ...READ MORE

Nov 17, 2018 in Blockchain by Christine
• 15,790 points
1,568 views
0 votes
1 answer

What Regex to use to identify a Block Hash?

Blockhashes are always 64 characters in length. You ...READ MORE

Aug 28, 2018 in Blockchain by digger
• 26,740 points
1,567 views
+1 vote
3 answers

What is the pattern for handling throw on a Solidity contract in tests

In my opinion the cleanest way is: it("should ...READ MORE

Sep 25, 2018 in Blockchain by Lupin
1,566 views
0 votes
1 answer

How to register a user in Hyperledger Fabric?

Best practice would be to leverage an ...READ MORE

Sep 5, 2018 in Blockchain by Christine
• 15,790 points
1,566 views
0 votes
1 answer

Hyperledger Fabric: PEM encoded certificate is required.

Hey, the syntax you are using is ...READ MORE

Nov 5, 2018 in Blockchain by Omkar
• 69,230 points
1,565 views
0 votes
1 answer

Invalid method parameters for eth_sendTransaction

params needs to be an array, try {"jsonrpc":"2.0","method":"eth_se ...READ MORE

Sep 28, 2018 in Blockchain by digger
• 26,740 points
1,563 views
0 votes
1 answer

How to select a single account in Ganache?

When you use web3, selecting a single ...READ MORE

Feb 5, 2019 in Blockchain by Omkar
• 69,230 points
1,562 views
0 votes
2 answers

Code to change owner

Hi, @Wilson, U have to write the require ...READ MORE

Oct 5, 2020 in Blockchain by Rajiv
• 8,910 points
1,554 views
0 votes
1 answer

How to get Node URL in private ethereum network?

You have already noticed that  admin.peers does ...READ MORE

Jan 10, 2019 in Blockchain by Omkar
• 69,230 points
1,549 views
0 votes
0 answers

Couldn't find network parameters file and compatibility zone wasn't configured/isn't reachable

After ran this command java -jar network-bootstrapper-VERSION.jar --dir <nodes-root-dir>.The files is generated.After ...READ MORE

Jun 20, 2019 in Blockchain by anonymous
1,542 views
0 votes
1 answer

How can I call a contract from another contract?

There are two ways to solve this. ...READ MORE

Jan 23, 2019 in Blockchain by Omkar
• 69,230 points
1,540 views
0 votes
1 answer

Hyperledger Docker: Error building images: cannot connect to Docker endpoint.

Check your container environment variable: CORE_VM_ENDPOINT=unix:///var/run/docker.sock Then if you ...READ MORE

Nov 15, 2018 in Blockchain by Omkar
• 69,230 points
1,538 views
+1 vote
1 answer

Error while sending a transaction from Web3py to a Smart Contract in Remix

You get the revert error when a ...READ MORE

Dec 12, 2019 in Blockchain by Vivek
1,537 views
+2 votes
1 answer

What are the wallet path credentials for Web3j?

Follow the below steps: Go to the private ...READ MORE

Aug 2, 2018 in Blockchain by Omkar
• 69,230 points
1,536 views
0 votes
1 answer

How do transactions create a new block in Blockchain?

Bitcoin puts a cap of 2,400 transactions ...READ MORE

Aug 10, 2018 in Blockchain by Christine
• 15,790 points
1,531 views
+1 vote
2 answers

Hyperledger Composer: "No version of composer-cli has been detected" after global installation

I am also facing a similar issue, ...READ MORE

Sep 20, 2019 in Blockchain by sam
• 160 points
1,530 views
+1 vote
1 answer

What is the best way to search for an item in blockchain?

All transactions and records in blockchain are ...READ MORE

Apr 21, 2018 in Blockchain by Perry
• 17,100 points
1,521 views
0 votes
1 answer

How to get account with ethers by default in ethereum private network?

Have you created an account before allocating ...READ MORE

Jan 9, 2019 in Blockchain by Omkar
• 69,230 points
1,520 views
0 votes
1 answer

Go build fail, fatal error: rocksdb/c.h

I followed here and it is done. https://github.com/openblockchain/obc-peer/issues/885 Configure ...READ MORE

Sep 17, 2018 in Blockchain by slayer
• 29,350 points
1,519 views
0 votes
1 answer

yfinance Crypto symbol list

After what I know about, YahooFinance uses ...READ MORE

Mar 24, 2022 in Blockchain by Rahul
• 9,670 points
1,516 views
0 votes
1 answer

In Ethereum Solidity, what is the purpose of the “memory” keyword?

Without the memory keyword, Solidity tries to declare variables ...READ MORE

Nov 15, 2018 in Blockchain by Perry
• 17,100 points
1,514 views
0 votes
1 answer

Connection failed to Ethereum Ropsten Testnet network.

 It looks like your node isn't syncing ...READ MORE

Mar 27, 2018 in Blockchain by Christine
• 15,790 points
1,510 views
0 votes
1 answer

How to check history of blockchain.info wallet?

In the link you mentioned(https://blockchain.info/q), there are ...READ MORE

Jul 23, 2018 in Blockchain by slayer
• 29,350 points
1,508 views
+11 votes
4 answers

How do I create an ether wallet?

The Ethereum Wallet is a gateway to decentralized applications ...READ MORE

Sep 14, 2018 in Blockchain by Shiva
1,505 views
0 votes
1 answer

Is it possible to send eth to a contract through its constructor from another contract?

I found the solution for this: pragma solidity ...READ MORE

Sep 26, 2018 in Blockchain by slayer
• 29,350 points
1,500 views
0 votes
1 answer

How to ensure data privacy in Hyperledger Fabric?

There are different ways data privacy in ...READ MORE

Jan 31, 2019 in Blockchain by Omkar
• 69,230 points
1,496 views
0 votes
1 answer

GetState query via chaincode always returns empty value

fabric uses an ccenv image to build the chaincode when ...READ MORE

Jul 17, 2018 in Blockchain by Christine
• 15,790 points
1,496 views
0 votes
1 answer

Ethereum solidity: Unable to get value from another contract

I have faced similar issues when compiling ...READ MORE

Oct 15, 2018 in Blockchain by Omkar
• 69,230 points
1,490 views
0 votes
1 answer

Error: Error trying to ping. Error: Error trying to query business network. Error: Connect Failed

Run the following commandbefore updating: composer network start ...READ MORE

Jun 28, 2018 in Blockchain by Perry
• 17,100 points
1,490 views
+1 vote
2 answers
0 votes
1 answer

How do I start mining on my private chain?

You could try deleting the datadir/.etash and ...READ MORE

Jul 13, 2018 in Blockchain by Christine
• 15,790 points
1,487 views
0 votes
1 answer

PHP IPC with geth Ethereum: How to communicate with client?

You have to use PHP Sockets $sock = socket_create(AF_UNIX, ...READ MORE

Oct 22, 2018 in Blockchain by Omkar
• 69,230 points
1,482 views
0 votes
2 answers

Laravel 5.4 to get data form API response

Input::get('var_name') READ MORE

Feb 14, 2019 in Blockchain by anonymous
1,482 views
0 votes
1 answer

My account is already an administrator but its giving the an error on denial of permission

Hi, @There, You can try this in your ...READ MORE

Jun 17, 2020 in Blockchain by Gitika
• 65,910 points
1,472 views
0 votes
3 answers

How to create a cryptocurrency based reward system using Ethereum?

Hey, you can take the help of ...READ MORE

Oct 28, 2020 in Blockchain by jamesright
• 140 points
1,471 views
0 votes
1 answer

Can I make my smart contract private in Quorum?

Yes, it is possible. You can look ...READ MORE

Jul 23, 2018 in Blockchain by slayer
• 29,350 points
1,470 views
+1 vote
0 answers

How to generate bitcoin address from XPUB

How to generate bitcoin addresses from XPUB ...READ MORE

Mar 9, 2022 in Blockchain by Soham
• 9,700 points
1,469 views
0 votes
1 answer

What is the default network that truffle migrates to when the config has 2 networks?

If --network is unspecified, it deploys to only development. You ...READ MORE

Oct 15, 2018 in Blockchain by Omkar
• 69,230 points
1,466 views
0 votes
2 answers

Creating a private/public key with 64 characters that are already known using bitcoinjs

//public-key var address = eckey.getBitcoinAddress().toString(); var privateKeyBytesCompressed = privateKeyBytes.slice(0); ...READ MORE

Sep 10, 2018 in Blockchain by Misty
1,461 views
0 votes
1 answer

Is there a way to get a trade history report from the Bitfinex API?

You can still fetch your private trades ...READ MORE

Aug 30, 2018 in Blockchain by Perry
• 17,100 points
1,461 views