Questions tagged [hash-algorithm]
A hash algorithm is any algorithm that can be used to map data of arbitrary size to data of fixed size. The values returned by a hash function are called hash values, hash codes, hash sums, or simply hashes. In Ethereum, the algorithm used is Keccak 256.
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How to detect `Keccak256` collision inputs
I'm trying to solve this -simple- small CTF challenge, the goal is to change the solver value to our address by calling the talk function:
// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8....
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MerkleTree hashing keccak256 in golang is different with in js
I am dealing with hashing keccak256 of address and amount to push to merkle tree in golang. I try to hash in js by using https://github.com/OpenZeppelin/merkle-tree lib and it is valid. but in golang ...
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How to implement Poseidon hash function into a smart contract
I am building a Merkle tree inside a smart contract, and I want to use the Poseidon hash function to later prove that an element belongs to the tree through a ZK proof. The problem is that I cannot ...
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Can PoS validators directly influence and choose the output hash of the block?
I'm interested in explanation for Ethereum Beacon [1] and also any forked EVM network [2] (Polygon, Binance, Fantom).
Here's validator turn to validate the block. Can he directly pick the set of ...
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PoSA(Proof of Stake Authority) and NPoS(Nominated Proof of Stake Authority?
The Proof-of-Staked-Authority (PoSA) consensus algorithm is a hybrid between the Proof-of-Staking and Proof-of-Authority consensus mechanism.
Nominated proof of stake, or NPoS, is similar to proof of ...
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Is there a way to change the block hashing method of private Etherem?
As all we know, Ethereum hashes blocks by Keccak-256 and this method used in private Ethereum too. Now, if we need to use Keccak-512 for hashing blocks in a PoA private Ethereum (For our project), ...
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if I put a message's sha256() hash on smart contract, can anyone recoverd the message?
If no one can recover the message, can I use this message as a "password" to some functions in the smart contract? like:
contract Test {
bytes32 hash;
constructor(bytes32 _hash) {
...
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How to correctly calculate the hash to sign of a transaction with Ethers? is "\x19Ethereum Signed Message:\n32" still necessary?
I am trying to get the public key of the sender from a signed transaction. I am getting the transaction information with the help of alchemy and quicknode. The response I get is a json object like ...
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How to determine if the hash is finalized?
For some reason, I am require to store the hash to database. I would like to know is there any criteria to determine that the hash is finalize?
For example,
Block #15000000 have hash value of
...
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Tornado Cash Hasher contract - circom
In the Tornado Cash constructor, it takes an argument:
Ihasher _hasher;
where the Ihasher is:
interface IHasher {
function MiMCSponge(uint256 in_xL, uint256 in_xR) external pure returns (uint256 ...
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What exactly is the output of a keccak256() function?
I've been looking through articles and youtube videos and I still don't get it.
I'm trying to get to a place where I can explain it to myself in simple terms (I'm still pretty new to coding).
What I ...
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Does SHA256 and/or Keccak consider current date time in hashing?
Does SHA256 and/or Keccak considers current date time in hashing? I am curious how it avoids or reduces chances of collision. With so many wallets addresses getting created, I hope there is some ...
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Can I get the IPFS hash from file (without uploading it & with java)?
As far as I'm concerned IPFS client uses the resulting SHA-256 hash from files, and also compatible with others, to index them in the IPFS Protocol.
My problem is that I'm not sure how to consistently ...
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Understanding Hash Lock Atomic Swaps
I have trouble understanding how exactly atomic swaps take place in HTLCs. Let's take the generic example:
Alice wants to trade 1 BTC with Bob in exchange for 15 ETH.
Alice creates a contract where ...
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solidity compiler hashing function
What hashing function or encoding scheme does solidity default compiler use to encode or hash the data of smart contracts in remix ide?
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How do I know what the hashing algorithm is for my BEP20 Token?
How do I find the hashing algorithm for the BEP20 Token that I created using remix.Ethereum? I am fairly new to the token world, but I managed to create a token. Here is the link to Bscscan if that is ...
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Check string similarity percentage
How can I efficiently check the similarity of two strings? Or better yet, if I have an array of strings, I want to check that the given string is less than e.g. 80 % similar to any of the other ...
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Why is this Javascript Ethash implementation returning a wrong hash result?
I'm trying to calculate the hash result for the "light" implementation of the Etash algorithm from ethereum/ethash/js but I can't seem to get the correct result.
The expected result for ...
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When is hashing used when creating a smart contract?
I was going through the solidity docs and in a contract example given I have seen keccak256 used.
// Perform checks to determine if transferring a token to the
// `OwnedToken` contract should proceed
...
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Solidity's keccak256 hash doesn't match WEB3 keccak hash
TL;DR: I have a method in a contract to calculate a keccak256 hash, and I'm trying to replicate it in Web3, but the hashes don't match. My problem is very similar to the one in this question, but the ...
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Hardhat local network keys generation
I noticed the generation of Hardhat local Etheruem network keys are found on the Mainnet.
Example:
After running npx hardhat node.
Accounts
========
Account #0: ...
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How to use bcrypt in a smart contract?
Is it possible to use bcrypt hash function in a ethereum smart contract? Or only keccak is available?
Searching I got to this question, where the OP apparently assumes it's possible, but there is no ...
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What is Ethash4G? Is it related to Ethash?
I've been toying around with the online crypto calculators, and stumbled across this on WhatToMine.
What is Ethash4G? Is it related to Ethash in anyway, and by extension, Ethereum?
Any insight would ...
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how to calculate the message part for pedersen hash in solidity
I am trying to implement pedersen hash using solidity. Is it possible to implement and how to split the message according to the conditions of pedersen hash.
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Why does proof of work targeted zeros always comes at the start of hash? why is it not in the middle or the end of hash?
My question is why always targeted zeros come at the start of hash of the block? I have never seen more than 2 zeros in middle or somewhere else in the hash of mined block... What's the reason?....
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Is it cheaper overall to store a keccak hash or to store a ripemd(keccak) hash?
As titled. I'm learning to build a DApp and I'm wondering if it's worth it to add the extra RIPEMD layer over keccak for a shorter hash to reduce storage costs.
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what is a pseudorandom cache mentioned in ethereum yellow paper
in ethereum yellow paper it says:
"There exists a seed which can be computed for each
block by scanning through the block headers up until that
point. From the seed, one can compute a pseudorandom
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Is any 40 character hex string a valid ethereum address?
I know an ethereum address is generated by getting the last 20 bytes of the keccak-256 hash of the public key, which is 40 hex digits. I also know, an address does not need to have transactions ...
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Building a deterministic wallet without random seed phrase instead multiple static inputs
If I want to be able to create a private key given inputs x,y,z and these inputs are constant, if I add enough entropy as a salt would it be secure to create a key this way (in terms of brute force ...
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How to verify the sha256 result of integer 5 in the Zokrates tutorial?
The Zokrates tutorial here starts with calculating the SHA256 hash of (the number) 5.
The hex representation of the result is shown at the bottom here:
However, I could not reproduce this on my ...
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Testing sha256(abi.encodePacked(_argument))
When trying to test a smart contract that uses
sha256(abi.encodePacked(_myargument))
I don't get the same hash on truffle !
I tried both
web3.utils.keccak256('_myargument')
web3.utils.sha3('...
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Need to help in adding bigendian support for Keccak256.cpp
Need help in making the keccakf function based on endiness in https://github.com/ethereum/solidity/blob/develop/libdevcore/Keccak256.cpp. I have gone through similar functionality at https://github....
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Hashnot matching generated from solidity contract and web3js
I want to make hash same as generating by solidity contract from web3 or ether's js.
In solidity contract hash generation by below :
sha256(abi.encodePacked(no of parameters)).
Kindly help for it. ...
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How does a message signed in Remix IDE?
What is signing method that is used in remix IDE and how is the hash value calculated from the message that is being signed?
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block-header hash verification
As part of a validation service I am working on, I need to be able to verify that the blockHeader hash was created correctly. Based on my understanding following are the steps to regenerate the header ...
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Match web3py hashing function to solidity hashing function
If I am using web3py to hash some data, like so,
msgHash = w3.soliditySha3(['bytes32','bytes32'], [dataBytes, saltBytes]);
What would be the correct way to hash inside of a Solidity contract and ...
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HMAC-x implementation for solidity
Is there any implementation of HMAC-SHA1 or HMAC-SHA256 or any other hashing algorithms for solidity?
I found this but it's not working.
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I want to compare hash that I have passed in the argument of the function but keep getting this error
function compare(string memory input, uint _y) public returns (uint){
bytes32 hashedinput = keccak256(input);
}
Error: Invalid type for argument in function call. Invalid implicit conversion from ...
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Calculating a hash of a set of keys in Solidity
I have the following problem that I'm trying to think of an efficient solution for.
Suppose I have a set of unordered keys (KEY_1, KEY_5, KEY_2, KEY_4), and I want to calculate a unique hash for this ...
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Why does a full client need to store the DAG?
The yellow paper says that miners and full clients must store the DAG dataset, but light clients can verify block headers by generating only a few necessary pages from the DAG.
It makes sense to me ...
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Why is this random algorithm not good enough?
Many lotteries on Ethereum use random algorithms to determine a 'winner'. For instance, this function is bad because has some vulnerabilities (read here about some):
function random() private view ...
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retrieving an original data from a hash: is it reliable?
Normally, one of the purposes of hashing a string (such as a transaction) is summarizing the data to save the size because of the space limitation.
If this proposition is true, now assume we need to ...
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How is the keccak256(a, b) function implemented?
I need to understand how keccak256(a, b) is implemented and how it differs from keccak256(a || b).
Is the content padded?
I need this because I do not want to allow for vulnerabilities where a user ...
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Common use cases for hashing functions? [closed]
I'm developing my first dapp with solidity and I was wondering in which cases should I use hashing functions like keccak. I know how they work but it is not clear to me when should I use them and to ...
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Hash of address pair combination where order is irrelevant
I have a contract where I often set stuff for a combination of 2 addresses. Because the parameters addressA and addressB are interchangeable I currently save the information redundantly.
Example:
...
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sha256() output
I used sha256() hash of a string and I got the following result
0x0de69f56365c10550d05e65ae8229dd0686f7894a807830daec8caa879731f4d for string Hello World2. Now I want to find out leading byte from the ...
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Hashing Algorithm - Multiple choices in Solidity
Is it possible to choose another SHA algorithm - say SHA256 - in Solidity? Anyone having issues with NIST compliance?
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Error deploying contract to my private network
I keep getting this "Error: The contract code couldn't be stored, please check your gas amount." message when I try to deploy my contract to the blockchain.
I read that is a generic error so I'd like ...
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From golang sha3 to solidity sha3
Trying to match "golang.org/x/crypto/sha3" lib
with solidity sha3() is giving me a hard time.
Its been discussed in here, but I somehow cant apply it in go.
How do I handle a big.Int type s.t i get ...
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Are Ethereum Contracts Vulnerable to Hash Table Poisoning Attacks?
Does anybody know something about this? I know that in general terms we will say not, but looking on the internet I found that isn't sure the answer to the question:
Can the EVM’s Internal ...
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