Sent BTC from Coinbase, blockchain explorer says Confirmed. Is recipient lying or could something else be the issue?

Sent BTC (approx $500) from Coinbase, Blockchain explorer says Confirmed. Is recipient lying they have not received or could something else be the issue such as his wallet? Recipient says it could be because his ‘hard’ wallet is set up in a way so it activates/acknowledges/receives with $1000 transaction minimum? He is meant to send […]

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Cryptocurrency Development Ethereum

How to use delegate call with or without arguments functions?

Below is my contract: contract A{ mapping (address => uint) public balances; function put() payable public { balances[msg.sender] = msg.value; } function get(address lucky) public { require(msg.sender != lucky); if (!lucky.call.value(balances[msg.sender])()) { revert(); } balances[msg.sender] = 0; } function() payable public {} } Now, I need to invoke the get function and the put function […]

Use hdseedid to give all addresses in bitcoin

I’m using bitcoin core version 0.18.1 and I’m studying Hd Wallet. I can see the value hdseedid, and I understand that it’s HASH160 of my hd seed. Can I use this seed to retrieve all my keys? I tried to put this value in https://iancoleman.io/ like entropia, but I don’t find the same address that […]

foManipulation of Bitcoin RPC with programmatically

I’d like to use Bitcoin source code(only RPC part) to manipulate with programmatically. I have bitcoind and bitcoin-cli installed in my local computer but I don’t know how to write code for my purpose. What I want to get senario is Writing the code that works like bitcoin-cli getblock <hash> Actually, I got same result […]

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Cryptocurrency Development Ethereum HTTP

Error while buying test ether from https://faucet.metamask.io/ – Mastering Ethereum

I am using Ethereum wallet MetaMask chrome extension and I am connected to Ropsten test network. I am following the instructions from the book Mastering Ethereum: Building Smart Contracts and DApps book by Andreas Antonopoulos and Gavin Wood. When requesting 1 ether from faucet I get the following error: {“error”:”[ethjs-query] while formatting outputs from RPC […]

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Cryptocurrency Development Ethereum

What is a hard fork?

I am new to web3 development. I have seen the word ‘hard fork’ in web3.js documentation, but I never understood it fully. I also noticed that hardfork is used a lot when talking about chains and different ethereum networks. I am not sure it if is related, but I would like to know what exactly […]

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Cryptocurrency Development Ethereum

REMIX debugger invalid opcode before JUMP

I am testing simple ERC20 token creation with the following in remix: pragma solidity ^0.5.0; import “https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.4.0/contracts/token/ERC20/ERC20.sol”; import “https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.4.0/contracts/token/ERC20/ERC20Detailed.sol”; contract TestToken is ERC20, ERC20Detailed { constructor () public ERC20Detailed(“TestToken”, “TKN”, 18) { _mint(msg.sender, 1000000 * (10 ** uint256(decimals()))); } } I launch the contract and debug, but prior to every JUMP opcode, i receive an […]

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Cryptocurrency Development Ethereum

How can Ethereum sustain short block creation times if the uncle transactions are not counted?

Lower block times are clearly desirable. Why does not Bitcoin reduce block creation times to 15 seconds just like Ethereum in this case? Because it would lead to too many forks. The main problem with forks is not the lack of rewards for stale blocks. It is the convergence time and wasted computation. Let us […]

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Cryptocurrency Development Ethereum

what is declaration error in remix ide and how to solve it

What is declaration error here! I can’t figure it out and the error is shown as an unidentified declaration error. Please help me out

Can bitcoind and btcd share a datadir?

I’ve already fully synced the blockchain with btcd, can I point bitcoind at the same datadir and use its contents?