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Cryptocurrency Ethereum Mastering Development

web3 providers for ethereum apart from metamask, to connect web and mobile dapps?

I want to create a list of ethereum web3 providers available apart from metamask, which could be used to integrate blockchain functionalities in our apps or dapps created in various platforms (web app, mobile web app, iOS, Android, even desktop apps). Could you please specify all that you know. Would be really grateful. Thanks in […]

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Cryptocurrency Ethereum Mastering Development

What does “gas limit” of a block limit?

Many people(one example) stated that “gas limit” of a block limited “gas limit” of transactions included in it. To verify, I downloaded a block (block number: 10185031) and added “gas limit” of all included transactions and found that the total sum of “gas limit” of all the transactions was much larger than “gas limit” of […]

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Cryptocurrency Ethereum Mastering Development

Ethereum Signing using HSM

I tried signing a Message using the SHA256withECDSA algorithm . It gives a different signed(r,s) output everytime. When i try to recover the address using the ecrevover method .it gives me a different address everytime. Does it mean Ethereum requires a constant r,s value for message everytime?

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Cryptocurrency Ethereum Mastering Development

How can I listen for Truffle Actions such as TX_BROADCASTED, TX_ERROR via the Drizzle Vue Plugin?

In my Vue JS Dapp, which uses Drizzle Vue Plugin, I listen for contract events using $drizzleEvents like so: this.$drizzleEvents.$on(‘drizzle/contractEvent’, (payload) => { this.contractEventHandler(payload); }); This works well for custom events emitted from my registered contract. However, how can I listen to general Drizzle Action events such as TX_CONFIRMAITON, TX_BROADCASTED, TX_ERROR, BLOCK_PROCESSING and so on […]

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Cryptocurrency Ethereum Mastering Development

Ethereum Skipping Empty Blocks –preload option doesnt work

In my clique PoA private network setup I try to mine skipping empty blocks and mine only when there is transaction present. I try to follow How to make miner to mine only when there are Pending Transactions? but I cannot notice that the mining works when I load he script with — preload followed […]

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Cryptocurrency Ethereum Mastering Development

what is parent transaction in ethereum

I am learning about ethereum, when I learn I came across a term Parent transaction Hash I would like to know regarding this

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Bitcoin Cryptocurrency Mastering Development

Recover corrupted wallet due to system crashed

My server was crashed suddenly and didn’t shut down bitcoin core probably, so now my wallet was corrupted due to it didn’t be released. I try to moved the corrupted wallet to a new server but it can’t be load: Wallet file verification failed: wallet.dat corrupt, salvage failed I have also tried to use pywallet […]

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Cryptocurrency Ethereum Mastering Development

How to connect with web3-eth-miner?

I have connect to my rpc geth via web3 successfully, but I can’t connect web3-eth-miner to my server. Here is my code var Web3 = require(‘web3’); var web3 = new Web3(); web3.setProvider(new web3.providers.HttpProvider(config.ethUrl)); const { Miner } = require(“web3-eth-miner”); const options = { defaultAccount: config.adminAccount, defaultBlock: ‘latest’, defaultGas: 1, defaultGasPrice: 0, transactionBlockTimeout: 50, transactionConfirmationBlocks: 24, […]

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Cryptocurrency Ethereum Mastering Development

Contract to test wrap & unwrap of ETH to WETH on Kovan ,while the wrap function is fine but in unwrap trx revert,is anything wrong?

trx fails at & debug at tenderly pragma solidity 0.5.12; contract WETH9_ { mapping (address => uint) public balanceOf; mapping (address => mapping (address => uint)) public allowance; function() external payable ; function deposit() external payable ; function withdraw(uint wad) external ; function totalSupply() external view returns (uint) ; function approve(address guy, uint wad) external […]

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Bitcoin Cryptocurrency Mastering Development

Transaction size limit across a single path in a Lightning Network and fee earned

Given MPP is included in the current version of lnd, an arbitrarily large transaction can be processed in the network. What is the transaction size limit across a single path? Is it still bounded to 0.0429 BTC (limited by max_concurrent_htlc)? What is the estimated fee earned (average as well as maximum) by a lightning node […]