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What is "Weak Subjectivity"?

Vitalik explains "Weak Subjectivity" in this blog here, but it's too difficult to beginners. Can anybody please explain this a bit more easily?
Satoshi Nakanishi
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Why do some blocks contain no transactions?

While poking through my Geth logs I noticed that block 1,000,006 doesn't actually contain any transactions. Why is that?
Richard Horrocks
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I got scammed or suspect scam on Ethereum. What to do?

This is a general question and answer on ethereum.stackexchange.com to all "I got scammed, please help" posts. This applies to you if you think: You have been scammed You think something might be a scam Popular scams include Fake investment sites…
Mikko Ohtamaa
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How to steal eth using delegatecall and selfdestruct

This documentation says Even if a contract’s code does not contain a call to selfdestruct, it can still perform that operation using delegatecall or callcode. This worries me. I've created some pseudo code to give a gist of a possible exploit. …
user1938620
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Where can I buy Ether?

Where are the best places to buy ether with the least resistance and lowest fees? Is there something like local bitcoin, but for ether?
high110
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How can I get a list of of transaction data which are sent to a specific contract?

I'd like to get a list of all transactions which are sent to specific contract or method of contract. What kind of way do we have to implement it?
Satoshi Nakanishi
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What are the limitations of proof of authority

The parity implementation of Ethereum provides proof of authority as an alternative consensus mechanism. I have not found much commentary about the advantages/limitations of this model for permissioned blockchains. For example let's imagine that…
Federico Squartini
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In Casper PoS, what is a finalised block?

Vitalik talks about block finalisation here, and Vlad also talks about it here. What is a finalised block? How long does it take to finalise a block? What are the security guarantees of a finalised block?
Randomblue
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What is the difference between a "call" , "message call" and a "message"

Is a transaction a type of a message? Is message call a call? And which of these results in any state change?
drequinox
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When to use abi.encode, abi.encodePacked or abi.encodeWithSignature in solidity

I am new to solidity. I have a doubt. How and when to use these different abi encoding techniques that are there in solidity and what's the difference between them. For example, should we abi.encode or abi.encodePacked the input for keccak256…
Radiant_Performer_39
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What exactly is a proxy contract and why is there a security vulnerability involved in it?

I was looking at the recent FE badger DAO exploit and this Twitter thread in it https://twitter.com/CryptoCatVC/status/1466380960648380419?s=20 One piece of advice the author gives before signing a metamask transaction is to inspect the etherscan…
Brutus123
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Bad Jump Destination error

I wrote what I thought was a dead simple contract - a saving jar... you add value ("save") into the jar and when the balance of the contract reaches a certain amount ("target"), then I am able to withdraw the value. But whenever I try to send it…
Daniel Mermelstein
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Why is an 'UNPREDICTABLE_GAS_LIMIT' error thrown when calling a view function created from a public variable?

I am using the Hardhat console to test my smart contract, which worked flawlessly until I removed the getter functions I wrote for my public state variables in favor of the automatically generated view functions. For example, I had a function like…
josephawallace
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Is it possible to build a private (permissioned) blockchain with Ethereum?

Ethereum is a great blockchain, but for some services the transaction fee is prohibitively too expensive. Is there any project and/or guideline on making Ethereum so it works on permissioned blockchains - i.e., with the consensus algorithm and…
MaiaVictor
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Testing for emitted events in Hardhat

I have a Solidity contract that inherits from ERC721PresetMinterPauserAutoId I want to write a test that verifies that a Transfer event has been emitted by the contract after the public mint(to) function has been invoked. Here's what my tests look…
imaginative
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