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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56
votes
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: ...
53
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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?
42
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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?
37
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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 ...
19
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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://...
19
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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, ...
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
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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 ...
18
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1answer
651 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 ...
17
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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 ...
17
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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....
16
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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 ...
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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3answers
5k views

Mining with geth on private network hangs indefinitely

I've got a private test network running as per this article. In particular my difficulty is set to 0x400; the entire genesis file I'm using can be seen here. Mining with geth does not seem to work ...
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 ...
14
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4answers
10k 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: { ...
14
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4answers
7k views

How to run Ethereum Wallet on a custom chain?

So I downloaded the Ethereum Wallet I know you can use a custom directory by running geth first with the datadir flag set up, and then launching the wallet. But besides a custom directory, I want to ...
14
votes
2answers
5k views

Running a custom private go-ethereum node cluster using docker

Here is a set up I have been working on and am having issues with ability to create a private network with peers. Basic set up: Used the dockerfile from https://github.com/ethereum/ethereum-dockers/...
14
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2answers
1k views

Is a fully private blockchain network immutable?

I always hear that immutability is one of the great assets of using blockchains in banks. An auditor can come and look at the list of transactions and it will trust them because blockchains are ...
13
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2answers
10k views

How many transactions are there in a block?

If a block acts as a ledger of transactions, how many transactions can fit in a block? I have to setup a private test net where only one machine is allowed to mine while (many) others are performing ...
13
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2answers
783 views

restricting sensitive information accessible from / linked to the blockchain?

I'm currently researching the practicalities of implementing a blockchain ledger whereby the company I work for, our competitors, our clients, our clients users (who we service indirectly) and an ...
12
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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 ...
12
votes
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 ...
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,...
11
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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
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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 ...
11
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2answers
3k views

How to connect etherwallet to my private blockchain?

I am unable to make etherwallet v3.4.2 to connect to my private blockchain. The way I run my private network: (please note that it works perfectly fine) geth --port 3000 --networkid 23422 --identity ...
10
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3answers
7k views

Difference between Ganache and Truffle

What is the difference between this two? I understand that Ganache is like a fake blockchain, but Truffle has that too ? What are the limitations of each and under which circumstance we use either ...
10
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2answers
2k views

What does it mean to “seal a block”?

In both the Ethereum chain specification format and in Parity's documents on private chains, you see the term seal a block. What exactly does that term mean? How is it different than mining a block?...
10
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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 ...
10
votes
1answer
1k views

Data sharing on the private blockchain

Assuming that there are multiple parties on the private blockchain, few general questions on the private blockchain usage: Can Personally identifiable information (PII) data be stored on blockchain? ...
9
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2answers
1k views

Accessing off-chain data from a smart contract to make a decision

I just started studying about smart contracts and from what I understand, smart contracts only deal with the data present on the blockchain. While working on a private blockchain, I want to know ...
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 ...
9
votes
3answers
4k views

How could “ethereum block explorer” connect into geth that is already running on the main server securely?

I am working on private Ethereum Network. I run Ethereum boot-node and Ethereum Block Explorer app ( https://github.com/etherparty/explorer (A lightweight ethereum block explorer.) ) on the main ...
9
votes
2answers
624 views

Geth will not start mining in private network!

Will somebody please help me out? I am stuck at this since hours; did the process +3 times, each time deleting the datadir content. Geth still will not start mining!! Specs: Geth 1.8.11, on macOS X ...
9
votes
2answers
2k views

Truffle: Hanging on “Deploying Migrations…”

I am deploying a contract on a private testnet. I am using Parity. When I type: $ truffle migrate --network my-network-name I get a popup in the Parity interface for a password to my account. I ...
8
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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 ...
8
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2answers
6k views

Private vs Permissioned blockchains

I have seen these two words - private and permissioned, a lot. Sometimes, they're used interchangeably. I don't believe these words have the same meaning. Can anyone give a detailed description ...
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() ...
8
votes
2answers
4k views

Getting more Ether on a private test net

I setup a local testnet using geth following these instructions. I was able to mine my initial Ether and all was working. After deploying some contracts I quickly spent all the Ether I had. Now it ...
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:...
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 ...
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: _______ ...
8
votes
3answers
2k views

Truffle migration stuck

I am trying to migrate contract on a block chain network created using azure ethereum consortium blockchain, But when I am running the command Truffle migrate it stuck at PS D:\sl\BCSLAC\bcdemo\sol&...
8
votes
1answer
1k views

Ethereum's definition of difficulty and hash rate

I'm trying to make sense of geth's hashrate and Ethereum's difficulty setting. I'm running a private test net and set the difficulty to a fixed value (to big.NewInt(250)) as described by https://...
8
votes
2answers
634 views

How to create a secure, production ready private chain?

I'm looking for more information or resources on how to run a private chain with ethereum with multiple nodes that would work in production and would only be accessible to my users/network. I know ...
7
votes
2answers
917 views

How can I get a private geth instance on Azure to interact with the public blockchain?

So I am referring to Microsoft Azure's new blockchain as a service Ubuntu geth instance. I've set this up no problem and have run through the tutorial, but I'm trying to think of how I would get this ...
7
votes
1answer
3k views

Executing custom JavaScript Snippets through Non-Interactive console (geth --exec)

I have a JavaScript snippet to get the latest transaction to/from an account. After starting the geth instance, I did this in the interactive JS console: jsFunction is a function in filename.js &...
7
votes
2answers
13k views

Ethereum Private chain Explorers [duplicate]

I have created a private blockchain by initializing a new Genesis block. Created few accounts and have now substantial amount of Ethers as well. I am able to deploy and execute my contracts on this ...
7
votes
1answer
1k views

Gas limit won't change [duplicate]

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 ...