Most viewed questions in Blockchain

0 votes
1 answer

Solidity error: SyntaxError: No visibility specified.

As mentioned in the error, you have ...READ MORE

Dec 12, 2018 in Blockchain by Omkar
 • 69,230 points • 6,889 views
0 votes
1 answer

geth: Fatal: invalid genesis file: invalid character 'â' looking for beginning of object key string

Looks like your editor is adding characters ...READ MORE

Dec 6, 2018 in Blockchain by Omkar
 • 69,230 points • 6,685 views
+1 vote
2 answers

Integrating web3 from Metamask: "ReferenceError: window is not defined" error

You can't use MetaMask on server-side because ...READ MORE

Oct 10, 2018 in Blockchain by Omkar
 • 69,230 points • 6,638 views
0 votes
1 answer

Hyperledger Fabric: “Local Fabric binary version does not match this newer version of BYFN and is unsupported”.

You need to first delete the existing ...READ MORE

Nov 19, 2018 in Blockchain by Omkar
 • 69,230 points • 6,588 views
0 votes
2 answers

“geth attach” command shows error: Fatal: Unable to attach to remote geth

please check from root, sudo -i geth attach READ MORE

Nov 7, 2020 in Blockchain by balachandar
 • 140 points • 6,586 views
+1 vote
3 answers

Not able to read a file from my assets folder

Hi.. I faced a similar problem in ...READ MORE

Oct 25, 2018 in Blockchain by Shrikanth
 • 6,523 views
0 votes
1 answer

Hyperledger Fabric: How to Parse arrays in req.body in node js express?

You can get the value from the ...READ MORE

Nov 16, 2018 in Blockchain by Kavya
 • 6,178 views
0 votes
1 answer

Call contract methods with web3 from newly created account

In fact, we can't just send transactions ...READ MORE

Sep 25, 2018 in Blockchain by digger
 • 26,740 points • 6,100 views
0 votes
4 answers

Hyperledger: byfn.sh up: ERROR !!! FAILED to execute End-2-End Scenario.

Try these commands $ docker rm -f $(docker ...READ MORE

Nov 28, 2018 in Blockchain by kartik chauhan
 • 6,033 views
0 votes
3 answers

How to solve “VM Exception while processing transaction: revert” error?

I am using windows 7. Any solution ...READ MORE

Apr 30, 2019 in Blockchain by Rajesh
 • 6,031 views
+2 votes
5 answers

How do I parse this JSON array in PHP?

/** * Firstly collect the ...READ MORE

Sep 3, 2018 in Blockchain by slayer
 • 29,350 points • 5,982 views
+3 votes
4 answers

How to solve “ERROR: manifest for hyperledger/fabric-orderer:latest not found” error?

I was having the same problem and ...READ MORE

Sep 6, 2018 in Blockchain by Rakesh
 • 5,963 views
0 votes
1 answer

If any etherium smart contract source code is not verified

To remove the “unverified” label, the human ...READ MORE

May 12, 2020 in Blockchain by Vikas Blockchained
 • 5,953 views
+3 votes
3 answers

How to validate bitcoin address?

I found these 2 scripts online: Javascript: <html> <head> <script type="text/javascript" ...READ MORE

Aug 17, 2018 in Blockchain by slayer
 • 29,350 points • 5,912 views
0 votes
1 answer

How to reintialize genesis block in geth ethereum?

You are getting this error because you ...READ MORE

Dec 6, 2018 in Blockchain by Omkar
 • 69,230 points • 5,889 views
+1 vote
2 answers

Hyperledger fabric: Error: got unexpected status: FORBIDDEN -- Failed to reach implicit threshold of 1 sub-policies

Try  ./byfn.sh -m down and then ./byfn.sh -m up READ MORE

Nov 5, 2018 in Blockchain by Omkar
 • 69,230 points • 5,796 views
0 votes
3 answers

Querying past transaction data from Hyperledger Fabric.

You can use shim function and query ...READ MORE

Apr 26, 2019 in Blockchain by Shaheen
 • 5,771 views
+1 vote
1 answer

How can I modify stored data in blockchain??

One of the important feature of a ...READ MORE

Apr 18, 2018 in Blockchain by Christine
 • 15,790 points • 5,758 views
0 votes
1 answer

web3.eth.sendSignedTransaction() always return “Returned error: nonce too low”

This bit of code looks wrong: var rawTx ...READ MORE

Oct 1, 2018 in Blockchain by slayer
 • 29,350 points • 5,628 views
0 votes
1 answer

"Migrations" exceeded the block limit (with a gas value you set).

In the error you have posted, in ...READ MORE

Jan 17, 2019 in Blockchain by Omkar
 • 69,230 points • 5,583 views
0 votes
2 answers

How to solve “sender doesn't have enough funds to send tx” error in Ethereum?

I also had the same error. I ...READ MORE

Mar 3, 2020 in Blockchain by Noha Abuaesh
 • 5,544 views
0 votes
1 answer

Know which exchange or wallet is behind a BTC address?

To answer your question, due to each ...READ MORE

Feb 28, 2022 in Blockchain by Soham
 • 9,700 points • 5,487 views
+1 vote
4 answers

Hyperledger Fabric: Failed to enroll admin: Error: Failed to enroll admin.

As your .hfc-key-store directory is in chaindev, Try running the following ...READ MORE

Nov 5, 2018 in Blockchain by Omkar
 • 69,230 points • 5,412 views
0 votes
1 answer

How to solve “insufficient funds for gas * price + value” error?

Change the following line Credentials credentials = Credentials.create(firstAccount); To ...READ MORE

Aug 1, 2018 in Blockchain by slayer
 • 29,350 points • 5,296 views
0 votes
1 answer

How to efficiently hash (SHA 256) in golang data where only the last few bytes changes

You can try the following examples on ...READ MORE

Jun 27, 2018 in Blockchain by aryya
 • 7,450 points • 5,271 views
+1 vote
1 answer

invalid sender error when trying to send signed transaction

Hi, i had the same error and ...READ MORE

Nov 16, 2018 in Blockchain by bublig737
 • 5,263 views
0 votes
1 answer

geth: Fatal: Error starting protocol stack: datadir already used by another process

It seems like geth is already running. ...READ MORE

Dec 6, 2018 in Blockchain by Omkar
 • 69,230 points • 5,163 views
0 votes
1 answer

Can not open geth console: Fatal: Error starting protocol stack: listen tcp :30303: bind: address already in use

The default port for geth is 30303. ...READ MORE

Dec 6, 2018 in Blockchain by Omkar
 • 69,230 points • 5,140 views
0 votes
2 answers

What is the difference between full node and partial node?

We need different types of nodes to ...READ MORE

May 31, 2019 in Blockchain by Sourav kumar
 • 5,126 views
+2 votes
2 answers

How can I traverse the blocks of transactions in hyperledger fabric?

For hyperledger fabric you can use query ...READ MORE

May 8, 2018 in Blockchain by Rachel
 • 5,106 views
0 votes
1 answer

How to create Bitcoin Address in PHP?

You need to understand that Bitcoin address and ...READ MORE

Aug 28, 2018 in Blockchain by Perry
 • 17,100 points • 5,088 views
+2 votes
3 answers

What are the functions of the Fabric CA Server and Fabric CA Client?

You need to setup the Fabric CA ...READ MORE

Aug 25, 2018 in Blockchain by Perry
 • 17,100 points • 5,046 views
0 votes
4 answers

Issue with getting web3.eth.accounts (MetaMask)

I solved problem, using: web3.eth.getAccounts((err, res) => ...READ MORE

Oct 12, 2018 in Blockchain by Perry
 • 17,100 points • 5,030 views
+1 vote
3 answers

Hyperledger Fabric: How to delete installed chaincode ?

One way to do it, that I ...READ MORE

Nov 19, 2018 in Blockchain by Omkar
 • 69,230 points • 5,020 views
+3 votes
4 answers

How do I add a new node on a Hyperledger network?

You can do this by generating the crypto ...READ MORE

Apr 7, 2018 in Blockchain by Christine
 • 15,790 points • 4,996 views
+1 vote
1 answer

Ethereum Error: authentication needed: password or unlock

First, make sure you have an account. web3.personal.listAccounts If ...READ MORE

Aug 8, 2018 in Blockchain by Omkar
 • 69,230 points • 4,994 views
–1 vote
1 answer

Not able to use geth attach

You are getting this error because you ...READ MORE

Jan 17, 2019 in Blockchain by Omkar
 • 69,230 points • 4,989 views
0 votes
1 answer

Hyperledger Fabric: Error: Error getting chaincode code chaincode: cannot find package

In the startFabric.sh launch the cli container ...READ MORE

Nov 12, 2018 in Blockchain by Omkar
 • 69,230 points • 4,986 views
0 votes
1 answer

How to set the ERC20 token price in respect to ether in solidity?

Hi, @Jas, I would suggest you go through ...READ MORE

Nov 9, 2020 in Blockchain by anonymous
 • 10,520 points • 4,959 views
+2 votes
1 answer

How to solve “SyntaxError: unexpected EOF” error in python?

There is not a problem in the ...READ MORE

Jul 30, 2018 in Blockchain by slayer
 • 29,350 points • 4,958 views
+1 vote
1 answer

Return array of struct from a solidity function: "Expected type name function getPurchaseOrderForVendor" error

There's a typo in your code. The ...READ MORE

Oct 17, 2018 in Blockchain by Christine
 • 15,790 points • 4,916 views
0 votes
0 answers

How to add a new organisation to an existing channel in hyperledger fabric without creating a new node/peer for that organisation. Can we add a organisation which does not contain any nodes?

May 2, 2019 in Blockchain by anonymous
 • 4,827 views
0 votes
1 answer

What is the difference between if() and require() statement in solidity??

If() and require() have separate functions and ...READ MORE

Apr 18, 2018 in Blockchain by Shashank
 • 10,400 points • 4,813 views
0 votes
1 answer

How to get return value from solidity contract?

Once you call a constant function, you ...READ MORE

Aug 16, 2018 in Blockchain by slayer
 • 29,350 points • 4,777 views
0 votes
1 answer

What's the difference between SHA and AES encryption?

You use SHA functions to take a ...READ MORE

Apr 7, 2022 in Blockchain by Aditya
 • 7,680 points • 4,753 views
0 votes
2 answers

How to generate ethereum qr code address with amount?

You implement this package: ethereum-qr-code. It implements the EIP67 standard which uses ...READ MORE

Sep 6, 2018 in Blockchain by Omkar
 • 69,230 points • 4,708 views
0 votes
2 answers

Chaincode Installation failed, Hyperledger Fabric

Hi, @Bhuwan, There must be an error in ...READ MORE

Oct 5, 2020 in Blockchain by Gitika
 • 65,910 points • 4,707 views
0 votes
1 answer

How to install truffle on Linux?

You can install Truffle using npm(node package manager). ...READ MORE

Feb 28, 2019 in Blockchain by Rishab
 • 4,690 views
0 votes
4 answers

Hyperledger Fabric: Error: 2 UNKNOWN: access denied: channel [contentbackchainchannel] creator org

Run the following command inside fabric-tools folder: ./teardownFabric.sh ./startFabric.sh ./createPeerAdminCard.sh Then ...READ MORE

Oct 29, 2018 in Blockchain by Omkar
 • 69,230 points • 4,676 views
0 votes
4 answers

Hyperledger fabric: enrollAdmin.js Error: Cannot find module 'fabric-client'

Change your directory to fabric-samples/fabrcar. And run: npm ...READ MORE

Nov 21, 2018 in Blockchain by Omkar
 • 69,230 points • 4,658 views
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