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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26
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3answers
10k views

What is a Shard?

Proof of Stake brings new concepts to the Blockchain ecosystem. In the dictionary "Shard" is defined as "A broken piece or fragment, as of pottery or glass".
22
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1answer
2k views

What would be needed to store the blockchain as a IPFS object?

In Christian Lundkvists blog post about possible uses for IPFS, he suggests that storing the Ethereum blockchain as an IPFS object could potentially decrease the size of the chain: We see the ...
22
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1answer
3k views

This image claims you can build “decentralized apps”, and each computer “contributes a little to process it”. Is that claim correct?

This image claims that you can put decentralized apps (say, a messaging program) on the Ethereum network. It also claims that each computer on the network contributes a little bit to the processing of ...
16
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1answer
4k views

What does it mean to “run code on the blockchain”? Wouldn't blockchain become huge?

More technically speaking, what does it mean to "run code on the blockchain"? Does it mean that we store the source code and then every full node runs that source code several times? If, for ...
16
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5answers
3k views

What is a blockchain? What is the concept behind it? [closed]

I have been going through some docs, and I understand that BlockChains are mostly like the building blocks in an Ethereum network. So, can someone give a dumbed down explanation/definition about what ...
13
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1answer
840 views

Why are contracts limited to only the previous 256 block hashes?

Why are contracts limited to only the previous 256 block hashes using the BLOCKHASH opcode (and corresponding functions in Solidity and Serpent)? Why does another contract, such as this, need to be ...
14
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1answer
5k views

What Ethereum blockchain explorers exist?

What blockchain explorers exist and What special features do they have? Are they open-source? How reliable are they (approximate uptime in %)? Is there a testnet version?
4
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1answer
621 views

Can geth and eth share the same accounts and blockchain?

It appears when I have multiple ethereum clients installed, that they all have their own data, accounts and even their own copy of the blockchain. Is it possible to share accounts and the blockchain ...
2
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1answer
329 views

How will the number of confirmations for security change with Casper?

How will this answer change when Casper is deployed?
56
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6answers
80k views

What number of confirmations is considered secure in Ethereum?

In Bitcoin, 6 confirmations are considered secure (very low probability of transaction/block reversal). What is the current number in Ethereum?
47
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4answers
23k views

What exactly is an Ethereum client and what clients are there?

What exactly is an Ethereum client? Is it a full network node that can post transactions to the blockchain (if that is the correct lingo?) or could it also be a light JS client that connects from a ...
83
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6answers
59k views

Ethereum block architecture

Where can I find a description (preferably a diagram like below) showing the block structure in an Ethereum blockchain? Credits: Wikipedia
14
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3answers
2k views

Is there a functional equivalent to Factom in Ethereum?

Factom is a distributed data and records management and audit system. How easily can what Factom does be done in Ethereum? Are there any working DAPPS doing this? Could a simple smart contract take ...
16
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1answer
3k views

What is state-trie pruning and how does it work?

Several sources mention the idea of state-trie pruning. What is that, and is it currently being implemented on the network? Is this a manual process or can it be done automatically? If Ethereum is ...
160
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7answers
118k views

What are the Ethereum disk space needs?

How fast is Ethereum blockchain growing and how big is it likely to get in the future? Is it still about 1 GB per month? Are there any data pruning or compression algorithms in place or planned to be ...
29
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3answers
14k views

How to create a Dapp from scratch on Ethereum?

Let's say we have someone who knows about blockchain but who doesn't have any background in blockchain-based application. That person wants to code an ethereum-based Dapp (decentralized application) ...
104
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11answers
81k views

How would I explain Ethereum to a non-technical friend?

I've recently attempted to explain Ethereum to several non-techy friends. My explanation usually involves starting with a comparison to Bitcoin, but this quickly becomes complicated as I then have ...
97
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6answers
25k views

How can a contract run itself at a later time?

In my blockchain application, I would like to have an event triggered at a later time, hours or perhaps even days after the application has most recently received a transaction from a user. How can I ...
75
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3answers
24k views

What is an uncle/ommer block?

The Ethereum blockchain is described as containing "ommer" blocks, usually called "uncle" blocks by the general public. What is an ommer/uncle block, and why are they needed?
9
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3answers
676 views

How do smart locks make sure that they have access to an up-to-date version of the blockchain?

Smart locks like Slock.it are supposed to allow locks to be able to do things based on the blockchain state. Does that work with locks that don't have their own internet connection? If so, how does ...
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 ...

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