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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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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1answer
530 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 ...
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1answer
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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 ...
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Error "Snapshot extension registration failed" when connecting nodes

Description. The error occurred during the process of building an Ethernet private chain, and I found that the node could not connect. The error message in the log is as follows. INFO [07-24|09:06:36....
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Difference between Ethereum Web APIs and Ethereum API as a service

I am approaching ethereum for the first time and I am reading the documentation. Can anyone explain the difference between Ethereum Web APIs (BlockCypher) and The Ethereum API as a service (infura)? ...
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3answers
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Problem In Getting Rinkeby Test Ethers

I tried to get rinkeby ethers from https://faucet.rinkeby.io/ by creating a tweet but the website shows "insufficient funds for gas * price + value” error. I also tried the website faucets....
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321 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 ...
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0answers
2k 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 ...
4
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1answer
437 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
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1answer
397 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 ...
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142 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 ...
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0answers
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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? ...
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1answer
200 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 ...
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35 views

ERC721 "NFT" with ImageURL[] instead of single ImageURL

I am looking to create algorithmic NFT's that are built from multiple images. Rather than layering the images for all combinations and then storing all permutations I'd like to send an array of image ...
3
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0answers
49 views

Retrieving the sender of a transaction

I am trying to retrieve the sender address within a transaction in Go and I am facing some issues. As I understand, in order to retrieve the sender of a transaction, you can either try to get the ...
3
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1answer
251 views

How to run Chainlink Project using eth-brownie python

I had installed eth-brownie using command pip install eth-brownie after Brownie installed.I had bake existing Brownie project into a new directory. mkdir MyChainlinkProject cd MyChainlinkProject/ ...
3
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1answer
84 views

Blockchain Performance Metrics

How can I measure blockchain execution time, latency and throughput? Which API do I use to measure? Anyone suggest any article or book for me to read about the blockchain performance metrics?
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1answer
650 views

How to download the blockchain of a single ethereum contract’s address?

The blockchain required to run ethereum is several Terabytes large. This means more than 9 years would be required to download it with my connection speed. In my case, I just want to know if the ...
3
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1answer
162 views

Are the timestamps of blocks for Ethereum only accepted when they are monotonically increasing?

Are the timestamps of blocks for Ethereum only accepted when they are monotonically increasing? If yes, why? And why other blockchains like Bitcoin and other blockchains with shorter block time can ...
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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 ...
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0answers
106 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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1answer
90 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 ...
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0answers
127 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......
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1answer
257 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
885 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
417 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 ...
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0answers
2k 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 ...
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618 views

In parity, how can I delete the last blocks I downloaded without corrupting the database?

I have found the blockchain data in parity. I go to overlayrecent folder and from there to the db folder. It looks like the blocks are the .sst files. How can I delete the last blocks I downloaded ...
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451 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 ...
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154 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) (...
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194 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 ...
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0answers
141 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, ...
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0answers
28 views

Using Eth-Brownie to fork mainnet from specific blockheight?

Can I use eth-brownie to fork mainnet from a specific blockheight? I have an archive node if that helps. I want to see what would have happened, instead of what will happen Can another service do this?...
2
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1answer
67 views

Get all ERC-20 token balances of address

What is the best way to get all the token balances of an address? I Monitor the while blockchain and got Like 6k token contracts Stored. IS there any way to get all token balances of an address ...
2
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1answer
62 views

How to concatenate an address to a string in solidity

I am trying to find the correct way to concatenate an Ethereum address to a string in Solidity v0.6.7 I tried the following but it did not seem to work : function append(string a, address b) ...
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30 views

Ensuring the atomicity of multiple transactions

I am new to solidity and have been creating single (both basic and complex) transactions. However, I have a question which I couldn't come up with a solution. How can I create 2 (or more) transactions ...
2
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1answer
38 views

Can you potentially mine for anything?

This is more of a general "blockchain" question and not specific to Ethereum so if I'm off topic here I would appreciate it if you could direct me to a more relevant stackexchange maybe. On ...
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2answers
70 views

why does it matter to sync nodes with time?

As we know, time gets set on a block's header as the miner's current local time. Each node while accepting a block, checks if the new block's time is more than parent 's time and is not also in the ...
2
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2answers
500 views

Solidity - Proper way to Import Contracts

When importing one Solidity contract into another, what’s the difference between importing it and accessing it using the is keyword, vs. importing it and just instantiating an object of it? Here’s ...
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0answers
62 views

What does sendSignedTransaction return?

I want to call a method in the smart contract (UpdateWeather) that goes through several steps before returning the result (an integer). I use sendSingendTransaction but I have doubts. Is the ...
2
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1answer
299 views

Solidity Integration of Multiple Contracts and a Library

I'm trying to understand the correct way to Deploy and then Import multiple Smart-Contracts and a Library when creating one big project. As an example, the project will have the following Library and ...
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0answers
273 views

What other blockchains support the EVM execution model?

In essence I'm interested in which other chains (mostly Layer 1) I can deploy Solidity smart contracts to? I know of TRON. And I also know Cosmos, Polkadot and NEAR have at least some support. But ...
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0answers
142 views

is "newBlockHeaders" in web3 emits a legit block?

I'm using web3.eth.subscribe('newBlockHeaders') to track transaction I sent to the blockchain. My question is that is the block emitted from "newBlockHeaders" legit or in other words, the block has ...
2
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3answers
459 views

What is meant by on-chain randomness? What is the difference between on-chain and off-chain operations in the context of randomness?

I want to understand on-chain and off-chain operations in the context of randomness. Kindly provide me an example so that its clear to me. I got one post here: What are offchain and onchain ...
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225 views

Why does Ethereum use JSON-RPC and not gRPC?

I am fairly new to networking protocols especially JSON-RPC and gRPC as they are not nearly as common in web development as REST. I was reading around and seems like gRPC generally performs better. So ...
2
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2answers
76 views

Duplicate data in "returnValues" field of event emitted in solidity script

I am using quoram distribution through Azure blockchain service.. we are emitting few events according to our logic and these events are being used to get specific data from the transaction.. though ...
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1answer
202 views

How to deploy blockchain app in heroku

I want to deploy my blockchain app in heroku and i just want to use ganache as my blockchain network. is that possible?
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Confidential data encryption on blockchain

I already built a supply chain that is able to collect product information on Ethereum. Now, that data can be confidential, but I still want to do Matrix calculations on it. I came across homomorphic ...
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0answers
30 views

How can I test a consensus protocol that I created?

Currently, I am designing my own blockchain consensus protocol and I want to test its performance. Is there any available tool or well-known framework that gives me this ability?
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2answers
1k views

error in remix IDE

I am facing this type of Error in 'remix IDE' while connecting it to 'web3.js@0.20.2' Error: Failed to decode output: Error: insufficient data for uint256 type (arg="", coderType="uint256", value="...

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