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Questions tagged [private-blockchain]

Private blockchains are not available for the public and are maintained/secured by a cluster of trusted nodes. These kind of blockchains are useful when dealing with sensitive information.

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53
votes
13answers
22k views

How do I set up a private ethereum network?

I'd like to set up a local (private) blockchain that isn't connected to the wider internet so that I can deploy some test contracts. How do I go about doing that?
19
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2answers
6k views

Deploying the Greeter contract via the geth CLI is not registering in my private blockchain

I am running a local private Ethereum blockchain using: geth --networkid 60098 --genesis CustomGenesis.json --nodiscover --maxpeers 0 --rpc --rpccorsdomain "http://localhost:3000" --datadir "./data" ...
18
votes
2answers
2k views

In a private blockchain, why do miners keep adding empty blocks to the blockchain?

I have been working on a private blockchain and observed that a miner, when started, keeps on adding empty blocks with no transactions to the blockchain. Why is this happening? It doesn't make any ...
57
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2answers
29k views

What does each genesis.json parameter mean?

I'm trying to setup genesis.json for my private network. What does each parameter mean and what value can I set in genesis.json? nonce: any data? timestamp: any time? parentHash: any hash? extraData: ...
37
votes
2answers
9k views

Is there a (theoretical) limit for amount of data that a contract can store?

Is there a theoretical limit to the amount of data that one contract can store while running in a private net in which gas is not a concern? Context: In a financial Dapp which is to replace global ...
12
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1answer
4k views

Peer discovery not working on private network

I'm running 3 nodes with the following command: geth --verbosity 4 --autodag --nat any --genesis /opt/blockchain/genesis.json \ --datadir /opt/blockchain/data --networkid 4828 --port 30303 --rpc ...
42
votes
3answers
22k views

What is a sidechain?

The Ethereum subreddit has this post related to an Ethereum-Dogecoin sidechain. What is a sidechain? Could one sidechain be a private Ethereum network?
15
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7answers
8k views

Block explorer running on private network

Is there any application out there that allows me to explore the Ethereum blockchain in a private network? (something similar to what blockchain.info does to bitcoin or etherchain does to ethereum ...
15
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2answers
5k views

Truffle Migrations Account Locked Error with --network command

I have started a private blockchain using the command, geth --networkid 1337 --datadir ~/home/xyz/testnet --ipcpath /home/xyz/.ethereum/geth.ipc --rpc --rpcapi eth,web3 --rpcport 8545 --rpcaddr ...
2
votes
2answers
4k views

MetaMask and Access Ethereum Private Chain from other PC in the same network (for test)

My goal: To simulate the Ethereum blockchain with different clients. So, they create their own accounts, i.e. public/private keys, and store them locally. So all are for testing. Assume, I have set ...
19
votes
6answers
6k views

How to remove gas system from ethereum

I'm testing Ethereum with a complex contract which requires quite a lot of gas. And I'm testing (and will be running) a private network with controlled miners, so I don't need them getting any reward, ...
18
votes
1answer
658 views

Out of Gas invoking precompiled contracts on private blockchains

Why do precompiled contracts lead to Out of Gas on private blockchains? Some tidbits are provided in the Solidity docs but can it be explained more? It might be that you run into Out-of-Gas for ...
12
votes
1answer
2k views

Is it possible to change the block target time?

We're curious to know what factors go into block times in a private network with a limited number of validators. Is this fixed or can it be parameterized in any way? How is it related to block times ...
8
votes
1answer
1k views

Losing connection between nodes on private network

I have 3 nodes running on a private network. After asking this question, I've manually added node1 as peer to node2 and node3, so my network looks like this: _______ ...
3
votes
1answer
1k views

How to fork Ethereum from the current state?

I've read a lot of tutorials and guides that teach how to set up your own private network from scratch. However, how would I do that from the current state of the blockchain? Instead of generating a ...
19
votes
6answers
26k views

How to decode input data from a transaction?

I'm sending a transaction to an account with some data with the following command: eth.sendTransaction({from:eth.accounts[0],to:eth.accounts[1],value:web3.toWei(1,"ether"),data:web3.toHex("http://...
10
votes
2answers
6k views

Adding private network peers to Parity

If possible, I would like to use parity with my private ethereum network. This answer (https://ethereum.stackexchange.com/a/9148/4575) provides us a solution that geth will run on the background and ...
5
votes
2answers
5k views

What is a HD wallet for Ether and how to create one using nodejs?

I know the basics of blockchain and how to use geth. However, I'm curious to know how to build a wallet using nodejs. What I basically is that you can create a account using geth console (private ...
6
votes
3answers
6k views

Gas limit exceeded on private chain

I am currently running a private ethereum chain with 2 nodes. My coinbase address on the main node has plenty of ether so I went to make a transaction but got the error "Gas Limit exceeded". I noticed ...
6
votes
1answer
2k views

How can I create connected multiple blockchains?

I want to create multiple private blockchains over Ethereum testnet, which need to be somehow connected. Is it possible to have a node on private blockchain that is connected to the another node on ...
5
votes
1answer
2k views

Listing transactions in a private blockchain?

In a private blockchain, is it possible to list the transactions based on from and to parameters in a transaction. Is it possible to check the latest transaction from or to an address? Also, is it ...
17
votes
3answers
6k views

How to make Ethereum mining difficulty static for a private chain?

I have implemented private chain in ethereum but its difficulty level increases by time as a result the mining process slows down. Is it possible to make the difficulty static or disable it in testnet....
8
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2answers
2k views

Automatic peer discovery in a private blockchain

Is there a way to enable automatic peer discovery in a private network. As far as I know, the only way to connect to peers while operating on a private blockchain is to add them through addPeer() ...
17
votes
4answers
9k views

What is a chainID in Ethereum, how is it different than NetworkID, and how is it used?

Here it's described in Ethereum's go implementation. type ChainConfig struct { ChainId *big.Int `json:"chainId"` // Chain id identifies the current chain and is used for replay protection A few ...
8
votes
2answers
1k views

What are the trade-offs between Ethereum's public chain and private, permissioned chains?

I see a large number of news stories and companies talking about the possibilities for private or permissioned blockchains. What are the key tradeoffs between using a permissioned/private chain and ...
4
votes
1answer
2k views

What is a Private Proof of Authority transaction speed?

Is the max transaction speed for a PoA private network the same as the main network? About 20 transactions a second?? If it is faster, would that mean the Rinkeby network is more scalable than the ...
3
votes
2answers
2k views

Disable automatic pregeneration of DAG?

I am working on a private blockchain (currently block #16117). I have pregenerated the DAG for epoch 1 as well. So, I started the geth instance with --autodag=false. However, I still get the following ...
2
votes
2answers
740 views

How open local ethereum chain (leveldb) using Nodejs levelup package?

Read the article about how to get info from local chain, but example not work. My code stoped when i create connection to LevelDB of my local chain in var db = levelup(...): var levelup = require('...
6
votes
1answer
3k views

geth not connecting to private network

I am running a private blockchain and I have parity nodes that seem to be connecting just fine. I've gotten though some geth issues that I was having before but geth still won't connect. HOWEVER ...
2
votes
2answers
3k views

Setting Block Gas Limit in private blockchain?

In a private blockchain with Parity, what is the correct way to set the Block Gas Limit? When I go to "Transfer" and then specify an address in the "recipient" field, a red bar pops up that says: ...
1
vote
2answers
3k views

How to change to private network in etherum wallet?

How can I change to private network in the ethereum wallet. I just got two mainnet and testnet in the wallet. Appreciate your answers
1
vote
1answer
862 views

What happens if the block time changes to 5 seconds?

Related to this and this. The difficulty adjustment algorithm is: block_diff = parent_diff + parent_diff // 2048 * max(1 - (block_timestamp - parent_timestamp) // 10, -99) + int(...
0
votes
2answers
261 views

What would be potential problems with building “private” Ethereum network on AWS?

Suppose I have two EC2 instances on AWS that are running geth nodes. They have the same genesis block and are in synchronization because peering is setup with open port 30303 (by default is for ...
14
votes
4answers
11k views

getting error on max invalid genesis file: hex string has odd length

I am trying to create a genesis block on my mac for a local ethereum network but I am getting the error: invalid genesis file: hex string has odd length when i do it. My code is the following: { ...
2
votes
1answer
1k views

Minimize mining times for private blockchain

a title is pretty straightforward. I need to set up miners on a private blockchain to mine blocks as fast as possible. I have compiled a go-ethereum client with a constant value of difficulty but ...
2
votes
1answer
747 views

where are solidity contracts stored?

I am using geth for running my blockchain node. I wrote my contract in the console itself and it got deployed and mined perfectly. I could invoke the functions of the contract in the terminal. I want ...
1
vote
2answers
1k views

Is it possible to run multiple Ganache nodes for private test network?

I wonder if i can create my own private cluster as it can be done with Geth for development & test purposes : https://github.com/ethereum/go-ethereum/wiki/Setting-up-private-network-or-local-...
16
votes
3answers
25k 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 ...
11
votes
7answers
12k views

How to add peers on a private network?

I have created a private blockchain on two different machines. Now I want these nodes to connect with each other as "peers". I am using geth console. I have tried the following command: > admin....
11
votes
2answers
2k views

What is the safest minimum block time to use without having any problem on Proof-of-Authority consensus?

On the following blog, at very last paragraph, Vitalik Buterin mentioned that: Hence, a 3-second target block time (and 5s actual block time) may be quite viable. As usual, we’ll be more ...
8
votes
1answer
2k views

Private chain: Extracting the “data” from an account?

I have initiated and mined a transaction between two accounts. I also included a data field in this transaction. This is just random hex data. Here is the command: eth.sendTransaction({from:...
6
votes
2answers
876 views

Is it possible to change Proof-of-Work into Proof-of-Stake consensus algorithm of an on-going Ethereum private chain?

I have a on-going small private chain could be seen here. I have only few nodes, hence difficulty is pretty low and average block time is high (around a minute). So it can easily attacked with someone ...
12
votes
1answer
1k views

How many transactions per second can be processed by commodity hardware?

I am running geth on a private network with the following command: geth --datadir firstserver --mine --minerthreads 1 --networkid 1300 --rpcport 8000 --rpcaddr 127.0.0.1 --port 30303 --rpcapi="db,...
9
votes
1answer
1k views

How can I stop the block gas limit on a private chain dropping to the public chain default?

I've got a little private chain running which occasionally runs some rather labour-intensive transactions. I was able to set the initial block gas limit using the "gasLimit" parameter in genesis.json ...
8
votes
1answer
1k views

Private chain: Maximum size of “data” field in an Ethereum transaction?

The data field can be used to send arbitrary data in a transaction. I am aware that the amount of gas required increases with the increase in size of data, but, is there a limit to the size that's ...
6
votes
1answer
1k views

How can you implement two way pegged Ethereum <-> Ethereum sidechain?

If you want to create an Ethereum sidechain which is two-way pegged to main (public or private) Ethereum, how can you implement sidechain? For example, How can you lock ether? How can you verify ...
5
votes
3answers
4k views

How to execute Smart contracts on a private Blockchain network

I have created a private Blockchain network on my Windows system with one node. I have created accounts and was able to transfer ethers across them. Now I want to deploy smart contracts on this ...
4
votes
2answers
6k views

How does the Microsoft Azure Ethereum Blockchain as a Service differ from the platform offered by Eris Industries?

On Nov 2015, Microsoft announced with ConsenSys, the addition of Ethereum Blockchain as a Service (ETH-BaaS) on their Azure platform. Meanwhile, Eris Industries also have been offering, what appears ...
4
votes
1answer
761 views

Connection between peers never happen on custom blockchain [duplicate]

My app connects and mine the same blokchain on every instance, it uses the same genesis.json and network ids. Genesis: https://github.com/AugustoL/OpenContent/blob/master/genesis.json Web3 service ...
3
votes
2answers
798 views

Blockchain use case in healthcare

I am new to blockchain. I am trying to understand the use cases of blockchain as a technology in healthcare. There are number of articles about different cryptocurrencies. I was going through this ...