i want to know where is the privatekey and transation store in google chrome file using metamask extension. can you help me? it is in /Users/jackson/Library/Application Support/Google/Chrome/Defaul...

Every time I try to deploy truffle migrate --reset my Organization.sol contract, I get the following error: Error encountered, bailing. Network state unknown. Review successful transactions manual...

I was wondering what is the function of "discport=0" at the end of an enode address for an ethereum node. Also, I see that my enode address is populated with my IP address some of the tim...

EtherScan provides a API for transaction details It's part of Geth/Parity Proxy APIs by name eth_getTransactionByHash, But I am unable to get information what ERC20 token was transferred and how ma...

With this below solidity code I have tried to send ether to ethereum wallet address 0x1 via smart contract and it becomes failed. But, when I try to send ether to address 0x1 directly from my walle...

From this solidity doc I know that the constructor is called once when the contract is created. But are there other instances that the constructor is called? I am looking for all possible cases t...

I have two identical transactions, in this case sending same amount of tokens, that result in different actual gas consumed (NOT the cost, and a significant difference). Here are the tx hashes: ...

I'm interested in generating an Ethereum public key from a private key using Python. I've tried googling around and found some resources but these are all JS nothing using Python itself.

I'm running a parity peer connected to a custom blockchain (PoA), but I can't send a transaction, nor see the list of transactions of my account. I get the following errors (see error screenshot): ...

I am deploying a private ethereum blockchain (geth) on a virtual machine on Azure. Upon deploying my Solidity contracts on the blockchain and launching my NodeJS application to it, I am able ...

In Hyperledger we have something called a network admin and this admin will have access to all the cards and assets on the blockchain (at least I have tried to deny the admin access to assets using...

I want to create a viewable function (needs to return a string to the user) that searches a mapping for msg.sender and if the senders value is x, I want the contract to proceed accordingly. It all ...

I am trying to call a method on my ERC20 token contract. I am connecting to 'https://rinkeby.infura.io/' httpProvider. I can call() constant methods but when i want to change the state of the contr...

Does solidity have the ability to query transactions it puts on the blockchain, based on data in the transaction? By query I mean within solidity code running inside a smart contract (not web3.js r...

I was recently reading about blockchains and am very intrigued by this technology. I had a few questions regarding blockchains: Do Blockchains use web-sockets to transmit information between user...

What are the practical differences between these web3.py methods for sending a transaction? w3.eth.sendTransaction({}) w3.eth.sendRawTransaction(signed_txn.rawTransaction)

I am studying blockchain with Ethereum, and I want to use past transaction data in the Smart contract using Solidity. If I use Web3.js module in the program written in javascript, I can get these d...

I have an Ethereum contract with an event defined like so: event Apple(address indexed a, address b, address c); The event is fired and I can see the log in the transaction receipt. Via web3, w...

I am trying to send ERC20 tokens in python with web3.py using a local private key. With this code I can send ether: w3 = Web3(HTTPProvider('https://api.myetherapi.com/eth')) signed_txn = w3.eth.acc...

I'm unable to get an Ethereum LES getProofsV2 (or getProofs) request to produce a ProofsV2 (or Proofs) response with anything but an empty array of Nodes. This is for a request targeted to a GETH n...

I'm studying solidity programming, and I have a question on this line of code: Transfer(0x0,msg.sender,tokens); I don't understand what 0x0 means. Is it the new token address or is it the new sma...

I've tried to follow the go-ethereum guide for this but it seems out of date. I've tried looking around for a web3 library in Go but everything tries to point back to "use geth." From Go, how do I...

I am deploying a contract using truffle, and when I specify the gas limit as the gas I want to use for the transaction I always get the exceeds gas limit error. Why does this happen? edit What I a...

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), ...

I'm using PHP and curl with json to interact with my geth server. I'm able to do all I want except one thing: checking if user's inputted address is valid according to ethereum wallet format. I s...