questions and answers

Answers on crypto currency and blockchain technology questions. Bitcoin, Ethereum, Cardano, EOS.IO, Tezos, Iota, Stellar and many other topics. Only useful solutions!


How do I keep my Ethereum Wallet synchronised after the initial synchronisation

I have successfully installed and synchronised Ethereum Wallet and it has correctly brought in my test Ether purchase. How do I resynchronise to ensure more current transactions are recorded on my account? ....

Mia Mia: 28 minutes ago


I've tried everything from mining bitcoin to litecoin to other altcoins....why do I have no luck?

I am a beginner in the blossoming culture of crypto-currency, and unfortunately, it's beginning to feel as if 2015 is too late of a year for a laptop-user such as I to be able to start mining. I'm running an Intel HD Graphics 4000 GPU, and an Intel Core i5-3230M ....

Noah Noah: 58 minutes ago


Truffle fails to test ERC20 approval

A am implementing a custom ERC20 token inheriting from OpenZeppelin's StandardToken ( I override some of the functions but did not override approve or allowance. I write a test for approval: contract('MyToken', async(accounts) => { it("approve test", async() => { let token = await MyToken.deployed(); let approveResult = await, ....

Oliver Oliver: 1 hour ago


How to make a pay-to-rawmultisig transaction?

Using the default client's RPC calls, can I make a transaction that sends to a RAW multisig (not P2SH multisig) scriptPubKey? If I made a raw transaction, and edited the bytes in the scriptPubKey of one of the outputs, could I manually write in my own scriptPubKey? Hopefully, instead of ....

Olivia Olivia: 1 hour ago


How to validate the Chainlink price feed at a specific time

Suppose that in my solidity contract, I need to see the price of ETH in terms of USD at a specific time, say on January 1, 2021. I would like to use the Historical Price Data Feed from chainlink (URL below). I imagine that to achieve this, I would have ....

Alexander Alexander: 2 hours ago


Extending Issued ERC 20 Token

I have already issued my ERC 20 token. But I want to add a time locking functionality to the token so the tokens issued during pre-sale / ICO will be time locked in user's wallets. Is this possible? ....

Lucas Lucas: 2 hours ago


ComponentDidMount doesn' detect Metamask change account

I'm quite new to Web3 and Metamask and would like to ask how should I change the basic componenDidMount of the React truffle box so that it can detect and change accounts when I'm switching an account on Metamask. Here is the code: Class App extends Component { state = ....

Liam Liam: 3 hours ago


Cannot call function in openzepplin ERC1155 contract via web3/metamask

I am trying to call the balanceOf function in a pretty barebones openzepplin ERC1155 contract through metamask. I am using web3 only to generate the ABI, and metamask to actually send out the call. Here is my code for the call, const call = web3.eth.abi.encodeFunctionCall( { name: 'balanceOf', type: 'function', ....

Mia Mia: 3 hours ago


Will pooled staking be implemented using multisig deposits?

Would this be a valid implementation for an ether staking pool if the goal was to eliminate the need for depositors to forfeit control of their ether to the pool owner? Depositor creates a contract and sends the ether they wish to stake to that contract The contract controls 2 ....

Mia Mia: 4 hours ago


What will be happen if 21 million of bitcoins become the property of one?

Let's assume, that the day already came, when emission of bitcoins completed, and we have the 21 millions of bitcoins. Let's say it happen that all these Bitcoins at one moment became the property of one person (for example because of the vulnerability of the system), which says that will ....

Olivia Olivia: 4 hours ago