Questions tagged [bytes32]
The bytes32 tag has no usage guidance.
73
questions
2
votes
1answer
64 views
Most gas efficient way to check if byte array contains zeroes?
I have a contract that I pass data packed into an array of uint256 (as it's apparently cheaper to use uint256 over bytes32) and each byte in the uint256 contains positions referencing another array of ...
0
votes
1answer
20 views
When using mapping, why use an address over bytes32?
From an end user standpoint, they will never want to use the address for searching for mapped data when they could just submit a username for function parameters, so is there any specific reason why ...
1
vote
1answer
54 views
In Solidity, Is there any situation, when string is necessary?
In Solidity, Is there any situation, when string is necessary? Please can u explain when I should use string instead of bytes or bytesN? Thanks!
0
votes
1answer
131 views
How to pass bytes32[] array to call this function using web3 js?
I have a function
function multiERC20TransferTightlyPacked
(
ERC20 _token,
bytes32[] _addressesAndAmounts
) public
{
for (uint i = 0; i < _addressesAndAmounts....
0
votes
1answer
37 views
Combine BytesX and BytesY to create BytesZ?
I am working on a Solidity Smart Contract (^0.5.10) where I want to return an array of Ratings elements.
struct Ratings {
address restaurant
uint8 score
};
Since returning Rating[], string[]...
1
vote
2answers
95 views
How to convert string to bytes256 or arbitrary bytes?
I already know how to convert bytes32ToString and stringToBytes32:
function bytes32ToString(bytes32 x)
public
pure
returns (string memory)
{
bytes memory ...
2
votes
1answer
33 views
Event and method different address type
This is my contract
pragma solidity ^'0.5.2';
contract MyContract {
address[] public contracts;
event ContractCreated(address newAddress);
constructor() public { }
function ...
0
votes
1answer
81 views
how to format contract params expecting bytes32?
I have a contract that expects a bytes32 parameter called "topic" which I pass in like this:
web3.utils.hexToBytes(web3.utils.stringToHex("Weather"));
I also tried
web3.utils.stringToHex("Weather")...
1
vote
1answer
1k views
How to convert string to bytes32 properly?
In my solidity I'm using a mapping like this:
mapping(bytes32 => uint) items;
constructor() {
items["test"] = 2;
}
function getItem(bytes32 key) returns(uint) {
return items[key];
}
...
1
vote
2answers
1k views
How to compare two bytes32?
I was using strings before I read that using bytes is gas cheaper. Now I changed my strings to bytes32 but I don't know how to compare them. I need to check if two bytes32 are equal in the require ...
2
votes
1answer
2k views
Invalid bytes32 value [duplicate]
I am trying to learn about solidity so I just watch a tutorial about it, I already copy the same code as the tutorial but there is an error with bytes32.
Here it is:
That is the deploy code:
And ...
0
votes
1answer
494 views
How to convert plain text string variable to bytes32 variable? And how to store bytes32 in one variable after converting? [duplicate]
pragma solidity ^0.4.25;
contract Purchase {
address public sellerAddress;
constructor (address _sellerAddress) {
sellerAddress = _sellerAddress;
}
}
contract Buyer is Purchase {...
0
votes
2answers
1k views
bytes32/uint256 conversion
I am looking to take in a uint256 (in hex notation) and convert it to bytes32. For some reason I am not getting the same value after converting.
function test(uint256 genes1) public returns (bytes32) ...
1
vote
1answer
92 views
Information lost when getting string from byte32 Solidiy smart contract
I have a number as a string which I pass to smart contract function as a parameter. The function takes byte32 as a parameter.
Here is the node.js code for executing the contract function:
const app =...
3
votes
3answers
439 views
How do I check if a bytes32 variable in a mapping has been assigned value?
For example, for:
mapping(address => bytes32) public addressName;
which one of the following syntax is correct?
address _address = 0x...; //an actual address
require(addressName[_address]!="");
...
0
votes
2answers
281 views
Keccak256 check Key
So I need a function that checks if a key fits the hash of that said key. This is what I have:
function checkKey(bytes32 hash, bytes32 privateKey) public returns (bool success) {
require(...
1
vote
0answers
41 views
solidity variables to store decentralized identities keys — bytes32 sufficient for a ED25519 keys?
I am building a next generation decentralized identity solution. Would like to under which solidity variable is best suited to store decentralized identities keys -- bytes32 sufficient for a ED25519 ...
1
vote
2answers
1k views
How to convert bytes32 to string? [duplicate]
I input an string data as bytes32 type. Now i cannot return that string in readable form? any way to do that?
2
votes
0answers
274 views
Comparing solidity sha3 with web3 sha3 inside smart-contract
The problem is that sha3 in solidity returns bytes32 and I have a string returned from IPFS by oraclize, and if hash calculated in solidity and returned to web3js (bytes32 got interpreted as a string) ...
0
votes
1answer
174 views
copying bytes32 values from map to array
I am trying to copy stored values from a map to an array. I have the following code:
pragma solidity ^0.4.21;
contract test {
event LogTest(
bytes32[5] a
);
bytes32[5] arr;
mapping (uint=...
2
votes
3answers
6k views
Where can I find a string to bytes32 converter online?
So far I am using this solidity code
pragma solidity 0.4.24;
contract Converter{
function Converter(){
}
function stringToBytes32(string memory source) returns (bytes32 result) {
...
-2
votes
1answer
398 views
Why does keccak256() return bytes32 instead of uint256 in Solidity?
A hashing function outputs an integer that is 256 bits long... so why not store it as such?
0
votes
1answer
78 views
Convert two int128 variables to Bytes32 and back
For Bytes32 to 2x int128 I have working code. I've adapted code from this stack Exchange answer
function bytes32to2xint128(bytes32 z) pure public returns (int128 x, int128 y){
bytes16[2] memory ...
1
vote
1answer
411 views
web3.toAscii for foreign languages
I have a function that takes bytes32 _name as a parameter and store it in a struct.
Let's say _name is either Chinese, Korean, or Japanese and from app.js I would convert the _name to hex to pass it ...
6
votes
3answers
2k views
Convert bytes32 to address
Is there a simple way to convert a bytes32, e.g. 0xca35b7d915458ef540ade6068dfe2f44e8fa733c, to an address?
bytes32 data = "0xca35b7d915458ef540ade6068dfe2f44e8fa733c";
I tried casting it with ...
2
votes
1answer
211 views
bytes32 same length hex strings cost different gas why?
I can not understand the difference in gas for the following problem. I generated a sha256 hash value and the output i chose to be lowercase hexadecimal. So the output value is hexadecimal string of ...
0
votes
2answers
446 views
Solidity inserting data that maps addresses to arrays of bytes32 error
My contract is as follows:
pragma solidity ^0.4.21;
contract try {
mapping (address=>bytes32[10]) Map;
function try(){}
function fill_map(bytes32[10] _attributes) public {
...
1
vote
0answers
28 views
Gas estimation failed when trying to input a list of bytes32[5]
I am trying to create a struct as shown in the code below.
The function setData is intended to create an object of the struct, take the inputs (a string and a list of type bytes32[5]) and set their ...
1
vote
2answers
1k views
How to convert/decode Solidity bytes32 to Python string via web3.py
Inside a Solidity contract, I have this variable: zBytes32 = "HelloBytes32";
after Python web3.py retrieving that variable,
zbytes32 = contractInstance.functions.getzBytes32().call()
print(...
0
votes
1answer
384 views
Problem with invoking a function with byte32 parameter : “Given parameter is not bytes”?
We have a function as follows:
function newObject(bytes32 _id, uint256 number_of_sub_states, bytes32[10] sub_states_types, bytes32[10] sub_states_values, address _owner) public returns(bool success) {...
0
votes
1answer
397 views
Setting values of an byte array dynamically
If I set the values of an array as follows, am I wrong?
uint256 n = 0;
bytes32[n] example;
function getArraySize(uint256 arraySize) public returns(uint256 size) {
size = arraySize;
return size;
}...
1
vote
0answers
191 views
cannot get return variable(s) in javascript when using require in solidity
I have a function in solidity that returns a few bytes32 variables. I cannot for the life of me access those variables. Can someone please help?
function getData() public returns (bytes32, bytes32, ...
0
votes
1answer
269 views
Read String as bytes (Oraclize callback)
I have an Oraclize call that returns the following (a string):
"00000000000000000000000000000000000000000000000000000000000003e8"
Now this is 1000 (bytes32 hex)
You can check here: https://www....
2
votes
0answers
277 views
How to pass bytes32 value from javascript?
I am using truffle and Ganache. I wrote the following code in remix and its working. But when I use the same code with javascript I am getting runtime error
pragma solidity ^0.4.17;
contract ...
3
votes
1answer
2k views
Problem with bytes32 values
I am facing problem with bytes32.
Here is my sample contract:
pragma solidity ^0.4.16;
contract Test {
bytes32 public input;
function test(bytes32 _in) public {
input = _in;
}
}
...
1
vote
1answer
128 views
bytes32 comparison returning true when values are very near
Has this nagging question where bytes32 that are near to each other returns true on comparison.
truffle(development)> 0x5b3138302c3132302c3135392c3232332c36342c3135392c36392c323821311a == ...
1
vote
1answer
84 views
Fixed-size array issue
Maybe this question it seems to be stupid but is it possible to change elements of fixed-size array like bytes32. For example:
bytes32 _b32 = sha3(1);
_b32[0] = 100; // => Error
1
vote
1answer
446 views
Calling mapping (uint ==> bytes32)return 0x0000000
contract test{
mapping(uint8 => bytes32) public check;
uint8 [] public array;
function Adddata(string document, uint8 number) returns (bytes32) {
check[number] = sha256(document);
...
0
votes
1answer
1k views
string memory[3] memory is not implicitly convertible to expected type bytes32[] storage ref
I have the following (array of bytes32 types):
bytes32[] public allTokenSymbols = ["0x4554480000000000000000000000000000000000000000000000000000000000", "...
1
vote
2answers
363 views
Invalid Op Code - passing bytes32 array to a contract method called from another method of another contract
I've been banging my head on this one for some hours, I'd appreciate any help :)
This is a final edit to clearly state the issue: Is there a proper way to pass a bytes32 array to a method on contract ...
1
vote
0answers
107 views
Solidity extract a sub bytes32 from a source bytes32
I need to extract a sub-bytes32 from a source bytes32 so I wrote this solidity function:
function bytesOf(bytes32 source, uint start, uint count) private pure returns(bytes32) {
bytes32 result;
...
2
votes
1answer
179 views
Is it possible to change an already assigned bytes32 variable?
If I assign a bytes32 variable such as
bytes32 x = 0xffff;
but then I want to change the last byte (or any byte really) so that x is now 0xffaa, is there any possible way to do this? I want the ...
2
votes
1answer
189 views
Range of Bytes32
What is the unsigned range of a bytes32 type in Solidity?
I'm wondering the total number of unique expressible combinations. I'm assuming it is 2^8^32.
6
votes
1answer
2k views
How to check if a bytes32 represents an empty string?
Why does the require not throw here when I am passing an empty string for the _name param?
function MyContract(bytes32 _name) public {
require(_name.length > 0);
name = _name;
}...
1
vote
1answer
832 views
Uint to Bytes32 conversion — how does this make sense [duplicate]
Pretty simple code here:
pragma solidity ^0.4.13;
contract Oracle{
event Print(string _name, bytes32 _value);
bytes32 key;
function Store(bytes32 _key) returns (bytes32) {
key = ...
3
votes
2answers
468 views
Convertion from bytes 8,16,32 to String
I know it has been asked a lot of times but the newest post about this I could find was about 1 year old. To me it seems quite possible that things have changed since then. So my question: Is there an ...
0
votes
2answers
291 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 ...
2
votes
1answer
279 views
How can I split a 56 character input and store them in two Bytes32?
I want a function to accept, store and output 56 characters. My other question (How to return bytes array in Solidity Contract) shows that I tried to return bytes[], but it gives me an error:
...
1
vote
1answer
50 views
Dealing with mapping(string => string[])
I have a contract with different categories. We can assume them to be the following here:
Cities
Countries
Counties
Suppose I want to add a new city to the category cities. I'm assuming this has to ...
2
votes
1answer
176 views
How do I combine integers, to save gas on transaction data and storage?
For example, I have two integers: one is uint128, another is uint64. I want to store those two integers by converting them to bytes24. And when I use them, parse the bytes24 to uint128 and uint64.
...
