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Questions tagged [evm]

EVM is the Ethereum Virtual Machine, the protected, distributed "sandbox area" (virtual machine) where contract execution occurs, replicated on every node in the network. EVM is also the name of the bytecode that runs on the virtual machine -- what Solidity, Serpent and LL get compiled down to before deployment.

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Similar to currency-abstraction, could there be cryptography-abstraction (free market for digital signatures on a single state)?

Currency-abstraction for mining rewards was planned for Serenity, and so on, and so is out there as an idea. I thought about "signature-abstraction", so that different digital signatures could compete ...
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613 views

Ethereum Virtual Machine and Docker Containers

I'm trying to understand what are the constraints that wouldn't allow a Docker container to be used instead of creating the specific Ethereum Virtual Machine. I followed this link: https://forum....
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How does the “block parameter” work with RPC calls? Do light nodes have access to historical data?

I'm looking at the RPC spec. Many calls (eth_getBalance, eth_getStorageAt) allow for a custom "block parameter" where I can pass in any block number. How does this work? Does each node maintain a ...
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Optional Data Feed on the EVM, what does it mean?

I am trying to understand the idea of optional data feed for EVM in the accounting field especially. I usually read that you can use two fields with the first field being a domain to register and the ...
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1answer
15 views

Can I call a contract function in the “data” element via web3, especially when I am using conversion to bytes?

In other words, say In Python I have something like that: signed_txn = w3.eth.account.signTransaction(dict( nonce=w3.eth.getTransactionCount('0x0000000000000000000000000000000'), gasPrice = ...
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28 views

How dangerous the 'short address' attack is as of 2019, October and what ways there are to mitigate it?

From what I read there's a well public knowledge of reantrancy and underflows/overflows due to the cases of documented hacks and stolen ether - yet the short address attack seems less known. I know in ...
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11 views

What is EVM15 as a Solidity output target?

In the Solidity compiler help menu solc --help, I noticed that evm15 is one of the new compilation targets in addition to evm and ewasm. I know what ewasm stands for, but what's the difference between ...
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22 views

Loading modified contracts keeping the same super class

I am trying to implement upgrade of contracts. One pattern by [1] is to have a layer to resolve the actual address of a contract. I implemented that adding the Pausable manipulation. My idea was to ...
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12 views

TypeError: Function overload clash during conversion to external types for arguments

Why do I get following error "TypeError: Function overload clash during conversion to external types for arguments." when using compiler version ^0.5.0; but when I choose 0.5.2; and later releases ...
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37 views

address.call(abi.encodeWithSignature(“func(<param>)”, _params) doesnot work

contract C1 { uint public num; address public sender; function callSetNum(address c2, uint256 _num) public { (bool res,) = c2.call(abi.encodeWithSignature("setNum(uint256)",_num)); ...
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50 views

Instantiation of an EVM on goLang

I'm dealing with goLang on an go-ethereum fork. In order to query a contract endpoint I need to get a fresh EVM reference for properly call the contract. I've found there is a NewEVM function that ...
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91 views

Unhandled promise rejection (rejection id: 1): Error: Transaction has been reverted by the EVM:

I don't know where i'm doing mistake. I have deployed my contract through remix and truffle and it was deployed without any mistake but now i'm deploying it from web3 solc@0.4.24 version and EVM is ...
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40 views

Gas is 0 when executing CALL opcode?

I wrote a very simple smart contract like this: contract Test{ function test1(address payable addr, uint256 value) payable public { addr.transfer(value); } } And I compiled it using ...
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45 views

How does UTXO fit into this schema?

I have been rather confused by the eponymous web3 stack introduced by the Web3 Foundation. https://wiki.web3.foundation/en/latest/tech_stack/Layer-0/platform_neutral_computation_description_language/ ...
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25 views

Are current ethereum opcodes prices in pyethereum updated?

I am not an expert in opcodes for Ethereum, but I am wondering if their prices here [https://github.com/ethereum/pyethereum/blob/develop/ethereum/opcodes.py] are updated as the latest version used by ...
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28 views

Delegatecall not changing state

I was trying the code in https://gist.github.com/sogoiii/f0ced0a4e569b5f38d302e7072d78b43 to observe the difference between call and delegatecall. pragma solidity ^0.4.18; contract D { uint public ...
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26 views

Strange behavior of solidity program

After a long debugging I found that I had two following problems in a private ethereum network using geth: If I have a require statement then the code is not executed on the EVM. The solution I found ...
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40 views

get error code of “uint64 overflow” when create contract

when create contract in statedb, i get error code the error is gas uint64 overflow, the code data is not much and i just give it little gasprice, the code is following: func NewContext() vm.Context { ...
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29 views

How to call a function automatically when some condition gets false?

I am having a bidding session where every time a person Bids on some product it checks the condition if the bidding session is valid or not, I want to trigger a finalize bid function which will ...
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45 views

Why the same contract has more bytecode size in solidity 0.5 in compare to 0.4.24?

My earlier contract was compatible with solc@0.4.24. Now I am upgrading my contract to make it compatible with solidity 0.5 but it leads to an increase in bytecode size. AFAICT There is no change in ...
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1answer
88 views

Contracts are “instantiated” by the account creating transaction?

I read the following in a research paper: Short Paper: Formal Verification of Smart Contracts that: contracts are “instantiated” by the account creating transaction; this will allocate the ...
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35 views

What does #[$] or [$] mean in remix?

Can someone tell me what the #[$] or [$] in the remix assembly output means? I assume it's a placeholder for something yet to be determined but am unable to confirm if and what. For example: PUSH #[...
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69 views

How to call another contract via create and call in EVM?

I am reading the source code of EVM. And want to imitate a contract remote call. I made two contracts as below: callee: contract Called{ uint public myuint; function set(uint _var) { ...
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62 views

Why does this contract work on Ropsten but not on a private blockchain?

The following contract runs successfully in Ropsten but not on a private blockchain. I assumed it could be a gas issue. So I increased the gaslimit and started a new blockchain but I get the same ...
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61 views

Why would the gas cost be so high on a simple contract?

The contract does not run, it cannot get enough gas. Here is the txn - > > eth.getTransactionReceipt("0x069fdab662d9bb69f0af6a526c60289cb3d2cfa4cba1345fdd53e517cef136aa") > { blockHash: &...
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1answer
58 views

Why is eth.coinbase node based and not blockchain based?

I have tested with geth using --datadir and found that if I have more than one node created using personal.newAccount then the account data is not shared. This seems confusing to me. I believed ...
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1answer
254 views

Threat Model Question - Code Injection / ROP possible in Ethereum Smart Contracts?

I am trying to understand a basic threat model for Ethereum Smart Contracts, to perform some research on how existing attacks techniques may be applied here as well. Is there a risk of a contract with ...
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108 views

How to tell the contract deployed size? (Error: The contract code couldn't be stored, please check your gas amount.)

I get Error: The contract code couldn't be stored, please check your gas amount. whenever I deploy to any test network (rinkeby, ropsten) or the live network. Deploy to a local Ganache works perfect. ...
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1answer
226 views

Opcode for out of gas inside a message call

According to the Solidity documentation: A require-style exception is generated in the following situations: ... If you call a function via a message call but it does not finish properly (i.e. ...
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222 views

Smart Contract with web3j - Stored SHA hash returned is not the same as input

I have a contract that stores sha-256 hashes of documents (stored as bytes32). I also have a method to retrieve a hash that is mapped to a unique id for the document. However, when I retrieve and ...
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299 views

log output of modified function to geth console

To analyze the execution time of different opcodes I've created the following modifications to the go-ethereum file instructions.go: func opAdd(pc *uint64, evm *EVM, contract *Contract, memory *...