All Questions

2
votes
1answer
40 views

HD wallet public to public key derivation and non-hardened keys

This question is about hierarchical deterministic wallets and the bip32 standard which, as I understand it, allows you to deterministically derive child private/public key pairs from a master seed ...
0
votes
0answers
4 views

How to rewrite my transfer transaction?

So I've made a simple tx to transfer. And it has been broadcasted. But I did not calculate the gas price properly so the tx is in still pending status. That seems takes long time. What if I make ...
0
votes
1answer
143 views

JavascriptVM(remix) bug deploying multiple tokens

I'm currently coding a crowdsale for school in which the fictious participants can buy a token. During the first round the participants would also get a second token which would act as a governance ...
2
votes
2answers
231 views

In Quorum, between Raft and Istanbul BFT (IBFT) consensus, which has a better (faster) block confirmation time? Assuming Ceteris Paribus

In Quorum, to help decide between Raft and Istanbul BFT (IBFT) consensus, which has a better (faster) block confirmation time? Assuming Ceteris Paribus.
0
votes
0answers
4 views

Truffle and Ganache - do I need to set the same gas-price and gas-limit in both of them?

Or can I set different values? If I can set different values, then how will they be used in the system (i.e., what gas-price and gas-limit will apply in every transaction that I execute)? Here is my ...
0
votes
1answer
16 views

How to limit N bytes to value range using Oraclize Ledger-Proof Random Number — unfair raffle

Lets say you have 50 tickets to a raffle. You choose to return 4 random bytes from the ledger proof RNG(https://github.com/oraclize/ethereum-examples/blob/master/solidity/random-datasource/...
1
vote
1answer
134 views

How do I make an efficient lookup table?

I need a 110-length lookup table that stores numbers from 1 to 20. I think the solution might be to move the instruction pointer forward by the index, and then return. Is something like this possible?...
0
votes
0answers
33 views

Transfer ERC20 token from a smart-contract

I am facing an issue and I can't figure what's going wrong. It is a very simple scenario: A smart-contract, that implements ERC20 and ERC20Mintable from OpenZeppelin. pragma solidity ^0.5.0; ...
-1
votes
0answers
12 views

Wrong Txfee 10.143 Eth for 0.8 Eth transaction

TxHash: 0x913bbcc78ca3c56cb1531a99c0c5febba427427f322d86f74b52e4647dc558a3 Block #7103411 I made a mistake while I entered Txfee manually and Txfee : 10.143 deducted from my account. My wallet ...
0
votes
1answer
15 views

Tokens are not visible in meta mask

I have deployed my ERC223Token contract in my private blockchain. I have transferred some tokens to my wallet It is showing tokens in my mist wallet and remix as well, but it is not showing tokens in ...
0
votes
0answers
13 views

Is signatures from web3.eth/personal.sign deterministic and a safe to be used as seeds for private keys?

The first part of the question: if I give the same inputs (content and signing address) to the web3.eth/personal.sign, am I correct to expect the signature generated to be the same no matter how many ...
0
votes
1answer
17 views

truffle-contract: Contract has not been deployed to detected network (network/artifact mismatch)

I am running a private network and would like to use truffle-contract to interact with the contracts. Unfortunately it gives me this error: Error: Contract has not been deployed to detected network (...
1
vote
1answer
140 views

Who can participate in Casper?

From what I understand, non-validators will feel benefits from the change to casper. However, is it only validators that can actually participate in Casper? Is it correct that if you have etehreum in ...
0
votes
0answers
18 views

Invalid implicit conversion from bytes32 to bytes memory requested

Error in given code, Invalid type for argument in function call. return ecrecover(operationHash, v, r, s); And, function sendMultiSigToken (address toAddress, uint value, address ...
14
votes
3answers
22k views

How to set up a Private network and connect peers in geth?

I am trying to setup a private network and trying to connect peers. Currently I'm trying it on my laptop and desktop (both of them are connected to different internet). I run the below command in ...
1
vote
1answer
35 views

Etherbase/Coinbase account of private net is changed automatically

I am testing on a privatenet, and as I started the chain I have set the etherbase using miner.setEtherbase. However after few hours I see that my etherbase is changed automatically. eth.coinbase ...
0
votes
1answer
12 views

timed commitment using ethereum blockchain

I read this paper: https://eprint.iacr.org/2013/784.pdf that introduces the idea of Bitcoin-based time commitment scheme. In which if the commiter does not open his commitment before a specific time ...
2
votes
1answer
196 views

How to include an other contract from a different folder while unit-testing with truffle?

The folder structure is as follows: Examples | +- Multiply | +- Solidity | +- contracts | +- MultiplyContract.sol | +- UUIDProvider ...
0
votes
1answer
152 views

My transaction of 0.003 ETH from MEW shows “FAIL”

My transaction of 0.003 ETH from MEW shows "FAIL" in etherscan when checked with Tx. The required Gas was set as 170000. No reason is shown on the etherscan page. What must've gone wrong? Does the ...
0
votes
1answer
166 views

Building smart contract

I am trying to build a simple smart contract following the rules on the website below. https://medium.com/crypto-currently/build-your-first-smart-contract-fc36a8ff50ca For some reason after ...
8
votes
1answer
452 views

Ethereum mining pool centralization

There are a number of well known undesirable effects of mining pool centralization, primarily: increased risk of collusion a small set of pools effectively gain veto power on the evolution of the ...
0
votes
0answers
9 views

What should we do if s in the ecdsa signature is greater than n/2?

What should we do if s in the ecdsa signature is greater than n/2? As we all know, in the ECDSA signature of Ethernum, the output s must be smaller than n/2, where s is the signature output and n is ...
1
vote
2answers
205 views

How to display blockchain transaction receipt details in an Ethereum Dapp

In my dapp design, I wish to provide the user with an option to view Blockchain Transaction Receipt Details either by a link to sites like Etherscan or by providing full details on a separate page in ...
0
votes
2answers
37 views

How to choose between Ethereum, EOS, and TRON if I want to build a dapp? [on hold]

In 2018, Ethereum dapps has $2.6 Billion worth transaction volume in 2018; EOS has $3.45B; TRON has $600M. However, number of transactions on Ethereum is way less than EOS and TRON. Ethereum has a ...
2
votes
1answer
135 views

How to use evm compile?

I have been testing with evm and I am not getting any output. Code - pragma solidity ^0.4.18; contract d8 { function myBalance() pure public returns (uint) { return 880; } } My ...
0
votes
1answer
5 views

Ethers in a light node

Since a light node makes transactions from a connected full node, does a light node need ethers to make transactions or it uses the ethers from the full node?
1
vote
1answer
10 views

How to burn non burnable ERC20?

Suppose you received 250 HELLOCoins and you want to burn them. Unfortunately, HELLOCoins uses OpenZeppelin ERC20 which implements the following function: function _transfer(address from, address to,...
0
votes
1answer
152 views

How to build a blind voting contract in Solidity

Can we build a smart contract where it is not possible to see the actual vote until the voting period ends? One idea is to use hashing. Voters can send a hashed version of a vote. The problem with ...
0
votes
0answers
13 views

Algorand Consensus vs Ethereum 2.0 Proof of Stake

I studied Algorand and Ethereum 2.0 Proof of Stake. Algorand seems superior. Why can't public Ethereum adopt Algorand as its consensus mechanism? Algorand Agreement - Super Fast and Partition ...
0
votes
1answer
134 views

Solc “bin-runtime” not a command?

I can generate the .bin of a contract with solc as follows: solcjs --bin -o output contract.sol However running the following command: solcjs --bin-runtime -o output contract.sol Generates the ...
1
vote
1answer
177 views

metamask not allowing any transaction

this question might be a metamask problem but i am still posting here hoping someone might know the answer. I am building an application using ethereum smart contracts. I am using metamask chrome ...
0
votes
0answers
10 views

How to use a transfer function from an EOA holding a token to a contract address?

I am using an ERC20 token which is used by a smart contact, EOAs also holds tokens How can I use the transfer function for transferring tokens from the EOA to a different Smart Contract address . ...
1
vote
1answer
38 views

What is the behavior of solc with optimizer disabled?

When enabling the optimizer the documentation of solc tells you that you can choose between optimizing the gas cost at deployment or the gas cost at execution by setting the runs parameter. But what ...
0
votes
1answer
22 views

Error during Testing Contract using Ethereum-bridge for oraclize

I'm getting the following error when I'm trying to test (truffle test) my contract which uses Oraclize API 0.5 to get the ledger random from oraclize (datasource = "random"). I'm using solidity 0.5.0 ...
0
votes
1answer
149 views

How can I show on web3j a list of all the instructors added on my blockchain?

I need to show on an html a list of all the instructors that are set up on the list pragma solidity ^0.4.18; contract Owned { address owner; function Owned() public { owner = msg.sender; } ...
1
vote
1answer
140 views

Constantly “Waiting to be mined” after certain call in contract

I have a crowdsale contract, that seems to be working fine. It receives funds, and returns a token in exchange. However, once its past the deadline, and I run the checkGoal() function, the contract ...
2
votes
3answers
179 views

Hi, is Ethereum MIt licensed?

is Ethereum MIt licensed? Can we use it for business purpose?
1
vote
1answer
27 views

How can I get a snapshot of the whole ethereum blockchain?

I'm currently running a geth node (fast mode) on my machine. And I want to know is there any way to get a snapshot of the whole blockchain from geth? Thank you so much if anyone has any suggestions.
2
votes
2answers
144 views

Ethereum hangs after 3 days uploading the blockchain, do I even need the blockchain to have a wallet?

I have downloaded and run Ethereum Wallet 0.9.0 Mist. It started updating about 3 days ago. It runs, but then when it is very near the end, e.g. 300-ish blocks to go, it seems to slow down and stop. I ...
1
vote
1answer
18 views

how to get input of time in solidity?

I want to run a session for a product in auction , my product struct contains the time interval we need for being the session of the bidding. While initializing a product, I need to take the input of ...
2
votes
1answer
176 views

How to get 'defaultAccount' by Nethereum?

I'm using Chrome with Metamask extension. When I change the account, eth.coinbase value is always set to current one, so I can do the assign in JS code: web3.eth.defaultAccount = web3.eth.coinbase; ...
0
votes
0answers
17 views

Setting up the gas price

I wanted to ask that is there any chance by which i can save a particular gas price in meta-mask so i don't have to maximize it when ever i call a function. I want to save a gas price in meta-mask for ...
0
votes
1answer
157 views

Swapped BTC for ETH using Bity.com en MEW but lost funds

I used bity.com service to convert 0.2 BTC for ETH and bity did not deliver my ETH, is this a scam? This is the confirmation message i got on MEW: Your TX has been broadcast to the network. It is ...
0
votes
2answers
13 views

How to calculate the difference between what was transferred and what was sent / received?

Hi I'm trying to get some clarity as to what the difference is between what was Transferred Sent Received Shouldn't what's transferred and received be the same? Transferred means the amount that was ...
1
vote
1answer
142 views

how to implement an airdrop function inside a smart contract

I have a Erc20 token X and an Smart Contract A Smart Contract A contains 1000 X Tokens. How can an User get an defined amount of X Tokens from this Smart Contract? (something like an Airdrop) So ...
1
vote
1answer
15 views

Uint256 division in vyper (and solidity)

Floating point division is not supported in solidity as mentioned here: How can I perform float type division in solidity? I want to divide two uint256 numbers and save them as a decimal, retaining ...
1
vote
1answer
8 views

What to enter for NODE_ENDPOINT on blk.io explorer

blk-io/blk-explorer: https://github.com/blk-io/blk-explorer-free Hi, I'm relatively new to ethereum, and I am having difficulty implementing the blk.io block explorer (for my private ethereum ...
0
votes
2answers
21 views

Which ERC standard is suitable for an ICO token to have types?

There will be ICO with multiple cycles... Here, investors can purchase tokens and after a fixed window of 270 days, they can redeem it back. But within this window period, they can transfer tokens to ...
0
votes
1answer
138 views

I tried to cancel my token transaction

I just try to cancel my token transaction, I followed the instructions from here more than 1 day and my transaction are always getting reset. How to cancel that two transactions transaction to ...

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