Questions tagged [blockchain]

The Ethereum blockchain is a distributed database based on the Ethereum whitepaper specification and stores both the full transaction list and the most recent state.

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1answer
630 views

Block header structure change under Proof of Stake?

The yellow paper describes the below block header structure: This includes difficulty, beneficiary, mixHash and nonce values. Presumably these will be redundant under Proof-of-Stake. How will the ...
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0answers
96 views

Retrieve CHAIN_ID of the executing chain from a Solidity contract

Is there a way to directly be able to retrieve CHAIN_ID information about the executing chain from a smart contract? I know that for any chain that has EIP-155 implemented, CHAIN_IDs are retrievable ...
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0answers
314 views

What is the current size of the Ethereum State?

What is the current size of Ethereum's state in bytes? I am not asking about the size of the blockchain with blocks headers, transactions and receipts. I am looking for the size of all the structure ...
4
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1answer
410 views

Storing private data off-chain with a sharing feature upon request

My question is not very technical from an implementation point of view, but I am looking for advice to achieve a specific use case using blockchain tech. I would greatly appreciate any insights or ...
4
votes
1answer
673 views

Call write function, which doesn't change contract value

I'm new in smart contracts and faced with one problem. After deploying contract to my test local blockchain network, i try to set new value via setter, after that I call get method of contract and it ...
4
votes
1answer
282 views

Why does geth -light start importing block headers from 3297471

I've been using geth to download the blockchain (on full) and one of the requirements for my research involves the use of light clients. I used 2 computers to download the blockchain on the -light ...
4
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0answers
102 views

Did the ripemd precompiled contract get deleted?

A bug "caused account 0000000000000000000000000000000000000003 to be deleted in block 2675119, even though the deletion should have been reverted due to an out of gas error." Source Did account 0..3 ...
4
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0answers
129 views

Genesis.json permanence and updating the blockchain

I understand that the initial genesis.json attributes are a permanent thing, and it cannot be changed retroactively. But what I want to know is which parameters are changeable afterwards and how? ...
4
votes
1answer
116 views

Can someone share your geth export file with me?

I need to setup an archival node ASAP but the download takes around 1-2 block per second. With this speed it will finish in 2 months (if it doesn't stall, but it does, I have to restart it manually ...
3
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0answers
58 views

Zero Knowledge Range Proofs

I am new to the world of Zero Knowledge Range Proofs. I read the following on GitHub: https://github.com/ing-bank/zkproofs The Zero Knowledge Range Proof allows the blockchain network to validate ...
3
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0answers
81 views

Who hosts IPFS?

I'm trying to get my head wrapped around how IPFS actually stores files. There is no IPFS coin, so who is hosting these files and are they getting paid to host them?
3
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0answers
160 views

How to access txpool pending transactions using Netherum?

I want to get list of transactions which are in pending state & queued state in txpool. I can see these transactions in pool using txpool.inspect command. I tried code given in nethereum sample ...
3
votes
2answers
373 views

IPFS. Add a directory recursively with an HTTP api

Is there an HTTP api equivalent of doing: ipfs add -r resources/public where resources/public is a directory with a static website (index.html in the root, css, js etc). Doing: curl -F file=...
3
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0answers
100 views

Parity create testing transactions and blocks

For test purposes, I would like to make test blocks including test transactions against main net. For example I would like to make a transaction that sends one ether from 0x1234567... to 0x99999999......
3
votes
2answers
1k views

Error: gas required exceeds allowance or always failing transaction upon function execution

Problem The transaction fails because the transaction ran out of gas instead of it failing because the require condition was not met. It works fine before the solidity update to version 0.4.24. It ...
3
votes
1answer
183 views

Uncle blocks in Parity PoA blockchain

As I know that there is no competition for mining new blocks in POA blockchain as each node mines new block at its given time slot. I have a parity PoA blockchain setup with 5 nodes. While examining ...
3
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1answer
577 views

geth - admin,addPeer() and static-nodes.json don't work

I'm trying to connect two nodes (both miners) on my private network. They are based on the same VM in different data directories. They have different ports and are based on the same genesis file and ...
3
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0answers
280 views

SSL Support for Communication Between Geth Nodes

We are using private Ethereum network for a multi entity use-case. The problem is that all these entities geth nodes sits behind a firewall which only allows TLS traffic. The node that's broadcasting ...
3
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0answers
1k views

How to encode data payload in ETH transaction

I'm using python to sign and send ETH transactions, and would like to do the same for ERC-20 token transactions as well. I'm having trouble correctly encoding the data payload to invoke the transfer ...
3
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0answers
415 views

How can i confirm transaction in geth from other peer of blockchain?

I have a query , I have create a private blockchain in which one geth node1 is use for transaction taking and other one(node2) is for mining .They are peered with each other and perfectly ...
3
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0answers
121 views

Geth bus fatal error

My geth node (v1.4.18 on testnet) has unexpectedly go down throwing an error like this: I1028 04:46:29.305710 ethash.go:259] Generating DAG for epoch 44 (size 1442839168) (...
3
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0answers
184 views

Blockchain compression Suggestions

I am planning to do a course project on block chain compression so that network transfer time is optimized. I read somewhere that the EVM bytecode component of the blockchain can be compressed. Is ...
3
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0answers
139 views

Updated geth, now I am re-syncing the whole blockchain

This is the first time I have updated geth. I was at a build of geth from several weeks ago, and this morning I updated to 1.4.12. I downloaded the pre-built binary to a new location on disk, ...
2
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1answer
18 views

Etherescan Unique Address Growth Chart - How is it computed?

how does Etherscan get this information from the blockchain? Is it possible via using a web3 module? Any insight? https://etherscan.io/chart/address
2
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0answers
53 views

Error while importing Libp2p package in blockchain

I have installed some js-libp2p's packages on my Ethereum Blockchain-ipfs project and I wrote some codes like below. const TCP = require('libp2p-tcp'); const MulticastDNS = require('libp2p-mdns'); ...
2
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0answers
12 views

I am sending some ether from account[0] to account[1] using geth console. But the amount is not getting added to the receiving account

I tried to mine the transaction using miner.start() command, still account balance remains the same > miner.start(8) I0428 16:27:15.927553 miner/miner.go:136] Starting mining operation (CPU=8 TOT=...
2
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0answers
39 views

Automatic sign of Transaction

Is there any secure solution(without exposing a Private key of the user) to automatically sign transactions, which are requested from a DApp, so that user doesn't have to sign each of them manually? I ...
2
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0answers
217 views

How Merkle trees are implemented in a database exactly

I have just checked out these resources: What is a Merkle Tree? Beginner’s Guide to this Blockchain Component Using Merkle trees to detect inconsistencies in data Exploring the use of Hash Trees for ...
2
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0answers
121 views

Gas estimation failed

whenever I want to run this code I get this error "Gas estimation errored with the following message (see below). The transaction execution will likely fail. Do you want to force sending? VM ...
2
votes
1answer
61 views

Understanding what happens between transaction creation and block creation in Proof of Authority

I am currently writing my thesis where I'm investigating the potential of blockchain technology to become the underlying technology in a system that is create and record qualifications. I'm at the ...
2
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0answers
35 views

Transactions are not mining for accounts created by Nethereum.Accounts.Account method but works for accounts created by web3.Personal.NewAccount

Transactions are not mining & in pending state for long time, for transactions with accounts created using Nethereum.Accounts.Account(privateKey). But mining works for accounts created using web3....
2
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0answers
922 views

Mining hangs on Generating DAG in progress

I am trying to initialize rpc using the below command and start miner using miner.start(1); geth --rpcapi eth,web3,personal --rpc --networkid=15 Mining starts successfully with below logs but it ...
2
votes
1answer
174 views

Connecting to blockchain on azure using web3.js and websocket

right now, I am trying to write a service using web3 which will 'subscribe' to all 'perndingtransactions' on blockchain to perform further actions. web3 documentation says that 'Httpprovider' cant be ...
2
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3answers
248 views

Does Using Infura Breaks Decentralization?

Decentralized applications have a philosophy: they are immutable,secure and trustless applications. You can connect to Blockchain and be sure about that features. Infura is a great tool when ...
2
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1answer
38 views

Are there any forks or alternate flavors of Ethereum that allow cross-chain swaps between two EVM-like chains?

I’d like to run an alternative consensus protocol based on the geth client. Since geth already has a ton of consensus protocols, I was wondering if any coins on the market were able to do the ...
2
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0answers
41 views

can raiden network be used on ethereum PoA(proof of Authority)?

https://github.com/raiden-network/raiden can raiden network be used on ethereum PoA(proof of Authority) ? If it can , how to use it? Please help.
2
votes
1answer
320 views

How to change block generation period?in POA private ethereum blockchain

my genesis.json like that: "config": { "chainId": 333, "homesteadBlock": 1, "eip150Block": 2, "eip150Hash": "0x0000000000000000000000000000000000000000000000000000000000000000", "...
2
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0answers
135 views

Who created this alt-Ropsten blockchain and why?

I usually test on Rinkeby, but this week I have to test some mining stuff, so I tried to get synced up with Ropsten. Unfortunately, after 3 days of trying, I still haven't had any success. The main ...
2
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0answers
141 views

Can not access quorum's contract from webpage *CORS*

I am getting following error on browser's console while accessing contracts. Failed to load http://localhost:22000/: Response to preflight request doesn't pass access control check: No 'Access-...
2
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0answers
554 views

Hyperledger Fabric and Ethereum Blockchain Integration

How can I connect Hyperledger Fabric to the ethereum blockchain so as to make payments. I am recording the number of tokens to be alloted in the hyperledger system I want to access the data and then ...
2
votes
1answer
523 views

How to get multiple values from one function contract to another

I have two contract and in first contract it contains a function which is responsible for returning two values, one of string and one of integer. function getUserData(address userAddress) public ...
2
votes
2answers
346 views

How to check if blockchain is downloading correctly or not?

I've few questions: 1) How to check Eth chain is downloading or not? 2) Does chaindata folder contain the whole blockchain? 3) How to check if blockchain downloading is completed? 4) After ...
2
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0answers
123 views

Ethereumjs: How to save the blockchain / state

Ethereumjs noob here. Using the code below, I'm able to create a new blockchain and add blocks to it. But the blocks are not being saved to the database. var blockdb = levelup("./blockdb", {...
2
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0answers
98 views

Importing wallet into Mist using custom datadir

I'm having an issue that seems to be quite common but I haven't found a solution. I'm using Ethereum Wallet 0.9 and I have all the application data, including the blockchain on an external drive. When ...
2
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0answers
137 views

Read function returning blank array in geth

I have deployed a smart contract on geth which has 2 simple read, write functions in it. Then I called the write function; e.g. payment.place_order("Laptop", 10,{from:eth.accounts[0]}). After the ...
2
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0answers
476 views

Geth always returning a 0 balance?

i´m mining now for about 3 days with 3 rigs each with over 50Mh/s, but my balance is still 0. Does anybody know why ?
2
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0answers
160 views

Deploy Button is not responding

I am newbie to solidity, this is my first PoC on testnet, i am just trying to understand how things works. i am following the main tutorial on Ethereum website, under this URL https://www.ethereum....
2
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0answers
322 views

How exactly does a unique asset get tokenized?

Say I have a set of assets, each with their own serial# or unique Id. How exactly would I create tokens linked to each asset that could be traded on a 1 to many basis? (ie: trade this one special ...
2
votes
2answers
412 views

Help-A-Noob-With-Ethereum-Wallet-Blockchain-Download

I'm on a 2013 Macbook Pro / 16 GB ram / 512 SSD / 2.3 GHz I just transferred 3 ETH from my poloniex account to the Ethereum Wallet on my local machine. The thing is, the entire blockchain hasn't ...
2
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0answers
198 views

What is the blockchain download size and can i reduce it in some way?

I am currently on a connection with a download cap, and was wondering what the current download size for the whole blockchain was, and if i could reduce this download size to under 2 GB? I'm ...