92
votes
Accepted
What does each genesis.json parameter mean?
Genesis block Explanation
mixhash A 256-bit hash which proves, combined with the nonce, that a sufficient amount of computation has been carried out on this block: the Proof-of-Work (PoW).
The ...
- 9,663
76
votes
How do I set up a private ethereum network?
Creating a private testnet for Ethereum is actually pretty easy. In recent versions of geth, you don't even need to create your own genesis block, or any other complicated steps (many of the online ...
- 901
60
votes
Accepted
Is there a (theoretical) limit for amount of data that a contract can store?
Contract storage is a key of 32 bytes and a value of 32 bytes, so the maximum a single contract can store is around 1.46 GB (32^32).
False. There are 2^256 different keys, and each key can store 32 ...
- 3,076
52
votes
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What is a sidechain?
Put simply, sidechaining is any mechanism that allows tokens from one blockchain to be securely used within a completely separate blockchain but still moved back to the original chain if necessary. ...
- 22k
35
votes
Accepted
What is a chainID in Ethereum, how is it different than NetworkID, and how is it used?
How is it different than networkID?
ChainID was introduced in EIP-155 to prevent replay attacks between the main ETH and ETC chains, which both have a networkID of 1.
It's basically just an ...
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33
votes
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Difference between Ganache and Truffle
Ganache allows you to create a private Ethereum blockchain for you to run tests, execute commands, and inspect state while controlling how the chain operates. It gives you the ability to perform all ...
- 17.8k
24
votes
How to decode input data from a transaction?
If you've heard about the ethers js library, it provides a fantastic function named parseTransaction, I found it after a very long search as it wasn't mentioned in any online forums and I'm still ...
- 351
23
votes
Accepted
Fatal: Failed to write genesis block: unsupported fork ordering: eip150Block not enabled, but eip155Block enabled at 0 genesis block
Answer is to update genesis.json to include eip150Block:
{
"config": {
"chainId": 4777,
"homesteadBlock": 0,
"eip150Block": 0,
"eip155Block": 0,
"eip158Block"...
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22
votes
Accepted
How to decode input data from a transaction?
You can do web3.toAscii(transactionID.input) to return the data in readable format.
Read web3.toAscii
- 9,663
22
votes
How to decode input data from a transaction?
In order to decode data you can use a library called
abi-decoder
You will need to provide an ABI for the smart contract you want to decode, then just paste the input data. Very simple.
The only ...
- 472
19
votes
What is a sidechain?
Sidechain is a blockchain that runs in parallel to the main blockchain which extends functionality through interoperable blockchain networks allowing a decentralized way of transferring/synchronizing ...
- 1,171
19
votes
How to set up a Private network and connect peers in geth?
Setting up genesis block: The first block (block zero) of the block chain is called as the genesis block. This is the only block on the network that doesn't point to the predecessor block. By default ...
18
votes
Block explorer running on private network
I don't know of any block explorer source code / application you can deploy into your private network.
Here's my scripts to check and print blocks, uncles and transactions that can be used to ...
- 40.1k
18
votes
What is an HD wallet for Ether and how to create one using node.js?
HD Wallets refer to Hierarchical Deterministic wallets. They are wallets that, from a root, can generate multiple "child" private keys in a deterministic way. You only need to remember the &...
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16
votes
How do I set up a private ethereum network?
If you are just testing contracts I would recommend using a lightweight Ethereum node like https://github.com/trufflesuite/ganache-cli. This way getting your network set up is as simple as running:
...
- 1,691
16
votes
How do I set up a private ethereum network?
Some of the main steps involve specifying a networkId, and creating a genesis file (you can give your account a lot of ether!).
Rather than repeat what's been written, there are guides here and here.
eth♦
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16
votes
Accepted
Deploying the Greeter contract via the geth CLI is not registering in my private blockchain
Update Apr 23 2017
geth 1.6.0 has a breaking change to remove access to the Solidity compiler from within geth.
The workaround is detailed in How to compile Solidity contracts within geth with the ...
- 40.1k
16
votes
Accepted
How to make Ethereum mining difficulty static for a private chain?
Modify the CalcDifficulty in Geth to return a static number, then rebuild Geth. Example:
func CalcDifficulty(config *ChainConfig, time, parentTime uint64, parentNumber, parentDiff *big.Int) *big.Int ...
eth♦
- 85k
16
votes
getting error on max invalid genesis file: hex string has odd length
I had the same problem and found that the issue was:
"extraData": "0x0",
If you change it to:
"extraData": "0x00",
The problem goes away.
At this point though you'll have another issue because ...
- 161
15
votes
Accepted
Running a custom private go-ethereum node cluster using docker
Summary
Check that there is network connectivity between the two Docker containers and reconfigure if necessary. Check there is sufficient memory allocated to each container.
In each Docker container
...
- 40.1k
15
votes
Accepted
What is the safest minimum block time to use without having any problem on Proof-of-Authority consensus?
PoA in Aura consensus engine of parity defaults to 5s, which has been tested to run with good stability. PoA network runs one such infrastructure.
I have tested for a 1 sec PoA using aura running ...
- 1,698
14
votes
Accepted
How to run Ethereum Wallet on a custom chain?
When you change the datadir using the --datadir flag you also change the IPC path that the Ethereum Wallet uses to communicate with Geth. When the wallet doesn't detect the socket it assumes Geth is ...
- 1,825
14
votes
What does each genesis.json parameter mean?
In addition to the fields described by niksmac:
config Configuration to describe the chain itself. Specifically the chain ID, the consensus engines to use, as well as the block numbers of any ...
- 37.6k
14
votes
Is it possible to change the block target time?
The block times in a private network and the public network is determined by the block difficulty adjustment algorithm. This algorithm is fixed in code, and is examined in more detail in How does the ...
- 40.1k
14
votes
Accepted
How to deploy smart contract in predefined contract address in private ethereum network?
It is not possible to deploy a contract to an address of your choice
The address a contract is deployed to is generated deterministically using the address of the deployer and the deployer's total ...
- 1,173
13
votes
What are the trade-offs between Ethereum's public chain and private, permissioned chains?
There are a number of key tradeoffs between a private (a.k.a. permissioned) blockchain network and the public, main Ethereum network. Here are just a few of them:
private blockchains require ...
- 22k
13
votes
How to decode input data from a transaction?
UI Tools
cleanunicorn.github.io/santoku
etid.wtd.ru
ethtx.info
moesif.com/solidity-abi-hex-decoder/decode
Note for these you will need the ABI of the contract.
Node Packages
@ethersproject/abi (...
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12
votes
How does the Microsoft Azure Ethereum Blockchain as a Service differ from the platform offered by Eris Industries?
Disclosure, I'm the CEO of Eris Industries
The major difference between the Consensys offering and the Eris Industries offerings on Azure are two fold.
At Eris Industries we are focused as @5chdn ...
- 576
12
votes
Accepted
How many transactions are there in a block?
The following is a simplified explanation of what geth does.
There are two main places where transactions can be: in a block, or in the transaction pool (txpool).
When a node first hears about a ...
- 7,280
11
votes
Getting more Ether on a private test net
If you are on a private net/chain you actually don't need to mine to get ethers, but just to confirm transactions.
You can fund your account(s) by specifying the amount in wei you want that account ...
- 2,461
Only top scored, non community-wiki answers of a minimum length are eligible