70
votes
Accepted
Get public key of any ethereum account
You can if and only if a transaction has been sent from the account. When you send a tx, you sign the transaction and it includes these v r and s values. You parse these from the signed tx and then ...
- 15.9k
49
votes
Accepted
What does v, r, s in eth_getTransactionByHash mean?
v, r, s are the values for the transaction's signature. They can be used as in Get public key of any ethereum account
A little more information, r and s are outputs of an ECDSA signature, and v is ...
eth♦
- 85k
44
votes
Accepted
Where is the private key for a contract stored?
Contracts do not possess private keys in the same way that your ether wallet does. Instead, they have programming code written in the language of the Ethereum Virtual Machine.
To determine what a ...
- 22k
28
votes
Accepted
Create and sign OFFLINE raw transactions?
ethereumjs-tx is a library with this example:
npm install ethereumjs-tx
const Tx = require('ethereumjs-tx').Transaction
var privateKey = new Buffer('...
eth♦
- 85k
27
votes
workflow on signing a string with private key, followed by signature verification with public key
I was having the same problem earlier, so I am going to give an extensive answer to how this works. I assume you are using geth as a client. There is an open issue where the geth client returns v in ...
- 1,786
24
votes
Accepted
Invalid sender error on private chain
The issue was that the chain id was not being set correctly. As a result transactions were signed with the incorrect chain id, so the sender could not be derived correctly. The fix was to also declare ...
- 844
24
votes
Accepted
How do you sign an verify a message in javascript proving you own an Ethereum address?
You can sign a string of data using web3.eth.sign
The address you use needs to be unlocked and you can sign text like this:
> web3.eth.sign(<your address>, web3.sha3("Some text"))
...
- 4,300
21
votes
Accepted
Is Ethereum secure against an attack by quantum computers?
Currently, Ethereum uses elliptic curve cryptography, which is not quantum resistant.
In the upcoming Serenity upgrade, however, accounts will be able to specify their own scheme for validating ...
- 36.7k
19
votes
Accepted
Ethereum ecrecover signature verification and encryption
v, r, and s are parameters that can be parsed from the signature. Here's a good example from the ethereumjs utils library:
var sig = secp256k1.sign(msgHash, privateKey)
var ret = {}
ret.r = ...
- 6,363
19
votes
Accepted
Using AWS CloudHSM to sign transactions
OK,
so when we (me and the ShaneT) implemented hardware signing (private key stored exclusively on AWS CloudHSM) there were a number of things we learned. Hopefully this gives you a guide on how you ...
- 338
18
votes
Accepted
How to properly create a raw transaction and sign it using web3 in browser
Below is working code that calls "increment" on https://programtheblockchain.com/dapps/counter. (More info about that sample here: https://programtheblockchain.com/posts/2017/12/13/building-...
- 27.9k
18
votes
How to properly create a raw transaction and sign it using web3 in browser
Using Web3.js 1.0.0
encoded = contractInstance.methods.myMethod(params).encodeABI()
var tx = {
to : myContractAddress,
data : encoded
}
web3.eth.accounts.signTransaction(tx, privateKey)....
- 934
17
votes
How can I sign a piece of data with the private key of an Ethereum address?
First, you'll need the private key for your account. To generate a brand new key, I use elliptic.js:
import {ec as EC} from 'elliptic';
const ec = new EC('secp256k1');
const keypair = ec.genKeyPair()...
- 991
17
votes
Get public key of any ethereum account
It is now possible to recover public key from Ethereum transaction without any coding:
Open the transaction in Etherscan.io
Click on vertical ellipsis in the top-right corner
Click on "Get Raw ...
- 7,273
16
votes
Accepted
How can I verify a signature with the web3 javascript API?
web3 does not support this feature yet, but it might be coming with web3 1.0.
In the meantime you can use ethereumjs-utils ecrecover feature.
Note that this function expects v to be in {27, 28}, and ...
- 1,786
16
votes
Accepted
What are the IDs for the various Ethereum chains?
1 Mainnet: https://ethereum.org
2 Morden Testnet (deprecated)
3 Ropsten Testnet (deprecated)
4 Rinkeby Testnet (deprecated)
5 Goerli Testnet: https://goerli.net
42 Kovan Testnet (deprecated)
11155111 ...
- 11.6k
16
votes
Accepted
Is it possible to sign a message in Solidity?
There might be implementations of signing in Solidity, but you shouldn't do it.
This is because in order to sign something, you will need a private key. Since every transaction is public on the ...
- 673
15
votes
Accepted
Is it safe to reuse Ether addresses?
Currently, Ethereum uses elliptic curve cryptography (ECDSA), the same as Bitcoin. So whatever "unsafe" concerns there are with how Bitcoin transactions are signed, would be the same with Ethereum ...
eth♦
- 85k
15
votes
Accepted
How can I sign a piece of data with the private key of an Ethereum address?
There's a functionality from the JSON RPC API not yet ported to web3 to sign data directly with one RPC function call, without messing with keys and crypto. If you don't need to sign messages ...
- 2,461
14
votes
How do you sign an verify a message in javascript proving you own an Ethereum address?
You can now verify signatures in web3 1.0 using web3.eth.accounts.recover
const account = web3.eth.accounts[0];
const signature = await web3.eth.sign("Hello world", account);
const signingAddress = ...
- 377
13
votes
Create and sign OFFLINE raw transactions?
In Go creating a signed transaction would look something like this:
transaction := types.NewTransaction(nonce, recipient, value, gasLimit, gasPrice, input)
signature, _ := crypto.Sign(transaction....
- 10.4k
13
votes
Accepted
Getting an address from ethereumjs-utils ecrecover
ecrecover returns public key, you need to convert it to address with pubToAddress.
pub = ethJsUtil.ecrecover(msg, v, r, s);
addrBuf = ethJsUtil.pubToAddress(pub);
addr = ethJsUtil.bufferToHex(...
- 2,966
13
votes
What if two ether functions have the same signature?
The function signatures need to be unique only within a contract. The Solidity compiler will detect and prevent collisions if they are not unique in this case. If you have fewer than 2^16 functions ...
- 9,112
13
votes
Accepted
How to get private keys on Truffle from Ganache accounts
You can start ganache with a mnemonic as a parameter ( -m 'jar boss sister abuse equal ....'). Doing this, you'll:
be guaranteed to have the same addresses generated with each run
be able to derive ...
- 2,615
12
votes
Accepted
Getting the wrong address back from ecrecover
Geth adds prefix to the message before siginig it in web3.eth.sign (see JSON-PRC spec).
Without this it can be possible to trick user to sign transaction (more here).
So, the correct code to sign ...
- 2,966
12
votes
Get public key of any ethereum account
I don't think this is possible, since you lose information when going from public key to address:
Start with the public key (64 bytes)
Take the Keccak-256 hash of the public key. You should ...
- 300
11
votes
workflow on signing a string with private key, followed by signature verification with public key
Here's a working example I tested out using truffle:
Example.sol
pragma solidity ^0.4.0;
contract Example {
function testRecovery(bytes32 h, uint8 v, bytes32 r, bytes32 s) returns (address) {
...
- 5,103
11
votes
Create and sign OFFLINE raw transactions?
You can use Web3.
var Accounts = require('web3-eth-accounts');
// Passing in the eth or web3 package is necessary to allow retrieving chainId, gasPrice and nonce automatically
// for accounts....
- 213
9
votes
Accepted
Can I web3.eth.sign with private key
N/A, in that you don't need to unlock an account at all.
Yes, see below.
The following uses Web3.js version 1.0.0-beta which is now the default installed by npm. Note that no node is attached.
> ...
- 9,112
9
votes
How to use ethers keccak256?
With ethers.js v5 you can use:
const { ethers, utils } = require("ethers");
const labelhash = utils.keccak256(utils.toUtf8Bytes("example"))
This is documented here.
- 4,375
Only top scored, non community-wiki answers of a minimum length are eligible