Questions tagged [ethereum-wallet-dapp]

Tag for the questions related to the deployment of the contracts using Ethereum wallet.

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1answer
281 views

web3.js new accounts without local node!

I am trying to develop an dapp, but since I am running a small server (Windows Sever 2012 R2) with limited space I don't want to host/install an ethereum node, nor geth in my server, because as many ...
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1answer
308 views

Truffle Develop Could not find suitable configuration file

Basically, after I installed the truffle the command: nom truffle -g . Then I went to set up the metamask on the google chrome. Once the metamask is set up then I try the command: truffle develop and ...
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1answer
32 views

Unknown wallet address on private development chain

Apologies in advance for the long post. I'm new to Ethereum and don't know which details are significant and which are not. I'm trying to learn about dapps by following an example in this book. My ...
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1answer
60 views

Estimation of gas in web3js 0.20

Q:- While sending only Ether One wallet to another wallet(NO SMART CONTRACT), do we need to define the default gas limit and price? i.e. 21000 * 3 OR 21000 * 4 OR 21000 * 5 etc Or I've need to use ...
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1answer
164 views

How to map multiple time and index value on same address

I wish to map the time to the address key. But currently it is working on the index key only. I just want to map time as well. Means the current time. So that I can able to get the record with time as ...
1
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1answer
125 views

Input byte array must be in range 0 < M <= 32 and length must match type-web3j

I have created an api to addCandidates. But when i run the api i get error: Input byte array must be in range 0 < M <= 32 and length must match type My codesnippet for addCandidates is: @...
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1answer
45 views

acess variable from token contract to ico contract , both placed in diffrent files

//token.sol pragma solidity ^0.4.24; /*import "./Ownable.sol"; */ contract ERC20Interface { function totalSupply() public constant returns (uint); function balanceOf(address tokenOwner) ...
0
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1answer
181 views

How to read previous blocks data?

I'm new to block chain technology. I'm trying to store and read blocks using testRPC along web3.js. I'm able to get the latest block data but not able to fetch previous blocks data. Please some one ...
0
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1answer
272 views

Uncaught Error: CONNECTION ERROR: Couldn't connect to node web3.min.js:1 http://localhost:8545

**Hi, I am doing a sample project on Ethereum where 2 fields ( Emp name, Emp Id) will be taken from the UI and set those values using a smart contract and show the values back to UI. Getting below 2 ...
1
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1answer
44 views

Allowing multiple polling for user

Is there a way to allow user to vote for multiple proposals. For example: User A can vote for proposals :P1,P2,P3,etc. Once A has voted for P1 he should not be allowed to vote for P1 but is eligible ...
0
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2answers
92 views

Require validation error not working

I tried using require method in solidity in the following way: require(validate(personName),"Error: Invalid Person") In this case i am checking if a person is already added to my person list. If not ...
0
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1answer
87 views

How get the private key using web3js?

is it possible to get the private key of ethereum wallet using web3js? I want to encrypt data using the ethererum keys?
0
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1answer
169 views

Infura API for mobile(ionic) app

I have one little question. Suppose I have private key of user in ionic app. Is this enough to make transactions using infura API and web3?
6
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2answers
1k views

Login system for DAPP without metamask

I'm building Dapp on Ethereum. Imagine I have companies to register in my dapp, I will provide them with their own smart contract and public and private key pair, which they will use to just unlock ...
1
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1answer
157 views

Golang How to slice Ethereum log events from smart contract to a more readable format

Im looking to use a channel to watch contract log events but the output returns a byte array like this the go code i am using looks like this package main import ( "...
1
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0answers
42 views

Case study : Blockchain as a service [closed]

I have a web application which has DynamoDB as the database. I want to store some SCORE in a DynamoDB table. How can I restrict this SCORE to only some set of people in my web application can modify ...
2
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0answers
45 views

Can one store short text data when transacting ERC20 tokens? [duplicate]

I am having trouble understanding if i can store short pieces of text when I send an ERC20 token. I have successfully stored a small message when transacting ETH by converting it to HEX and adding it ...
3
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0answers
24 views

Ethereum wallet accounts all use same password though I made different ones?

(tech level, beginner) installed wallet version win64-0-11-1 deployed a contract, made a token using the example code on ethereum site. had two accounts in the wallet. used main account to send ...
2
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1answer
169 views

msg.sender is Null in Base Constructor

When I create the child class object and try to access value of msg.sender from parent class it always comes 0. Can anyone please help me in this? Below is the sample code: contract Test1 is Test2 { ...
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2answers
143 views

My Private key from myetherwallet.com was stolen, Can I add more steps to access my wallet?

yesterday I was cheated by this MEW address user:0x83ecb676706aa5c7cf72384723935dd1195dcb3e He/She sent my 0.2549 Eth from my ETH Wallet address :0xe6b0d7f7d18c14015d47ecc77cf5c0009f34bb18 Shit!!! ...
1
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1answer
145 views

Installing Ganache GUI on windows 8.1

How to install Ganache UI on windows 8.1 ? I downloaded from Official website but after downloading i am unable to install it on my machine. I tried to install it through power shell but facing ...
2
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2answers
135 views

How do I update data for project using blockchain (Ethereum)?

I am very new to creating blockchain dapps, so some guidance would be appreciated. I am conceptualizing how to approach creating a private blockchain so that users can communicate about the status of ...
1
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0answers
73 views

Insufficient funds for gas * price + value Etherum Wallet

Version: `0.11.1` OS & Version: windows Node version: `geth 1.8.13` Number of blocks synchronized: 55 Private network I am testing with Ethereum Wallet using the private test network created by ...
1
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1answer
206 views

How to encrypt file before storing into IPFS network in Javascript? [closed]

I want to encrypt file before storing into IPFS network so that only person who is uploading a file should be able to decrypt.
3
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1answer
634 views

How to use mnemonic to recovery my ethereum wallet

I use web3j to create my ethereum wallet.the Code just like down import org.web3j.crypto.Bip39Wallet; import org.web3j.crypto.Credentials; import org.web3j.crypto.ECKeyPair; import org.web3j.crypto....
2
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2answers
169 views

First Time Ethereum Wallet User Setup Questions

I will try to make this a fast post with just a few questions I cannot figure out the answers to: I am trying to accept/send ETH payments and have downloaded, installed, and created a wallet using ...
1
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0answers
31 views

How can I implement ethereum If I'm making an exchange service like cex.io [closed]

I was wondering how cex.io manages ethereum service on their website. I know what happens with bitcoin. They have 1 wallet and daemon on their server for each coin. for example bitcoin. Then When I ...
0
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1answer
49 views

How to create withdraw token requests on my custom token sale dashboard

I created a token sale dashboard. Users can send BTC,LTC,ETH to dashboard. When user send BTC, LTC or ETH to dashboard, they get tokens to their dashboard budget (offchain) based on current token ...
1
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2answers
227 views

How to get all index value?

contract Bar{ struct Foo{ uint x; } mapping(uint => Foo[]) foo; function add(uint id, uint _x) public { foo[id].push(Foo(_x)); } function get(uint id, ...
1
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0answers
22 views

How to interconversion between privatekey and keystore with password in interactive console

When I execute geth attach attaching a active geth node into a interactive console . I could use keystore and password to sendTransaction . But now I only know the raw privateKey,How to execute ...
0
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1answer
71 views

Ethereum unlock account

Is there any way to unlock the ethereum account when using the infura api. Can only metamask do it? I would not like to use metamask because not every user has it on the browser
1
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0answers
128 views

creation of Hourglass errored: transaction execution failed

I don't know why I'm getting this error while deploying 2 of my contracts. creation of Hourglass errored: transaction execution failed while code compiles successfully no issues there. ...
0
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2answers
70 views

How does the User sign Ethereum transactions when interacting with blockchain via an web3j-based intermediate API?

We have a private Ethereum network running in our testbed. And a web3j-based (Java) API exposes various functionalities to the deployed smart contracts on the blockchain. The API connects to the ...
0
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2answers
52 views

ETC Stuck in ETH standard wallet contract

I used to use the standard wallet contract in Mist to store ETH and as a result have some ETC still stored in the wallet contract address according to the ETC block explorer. I am trying to figure out ...
0
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1answer
45 views

Need help with smart contract

My code on Solidity is: contract Recoverable is Ownable { /// @dev Empty constructor (for now) function Recoverable() public { } /// @dev This will be invoked by the owner, when owner wants ...
1
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0answers
24 views

trading a secret message with some person only after money is paid

I want to build a DAPP where person A trades a message with person B for ether. Since the message is secret, person A encrypts the message by using public key of person B and stores the message in ...
0
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1answer
162 views

Metamask stuck at Unknown network ID

I'm getting unknown network ID error on transferring a token in meta mask as in the image below. I'm using local network with ganache. I can transfer from metamask account to another after ...
0
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0answers
52 views

How does online wallets handle ERC20 tokens behind the scenes? [duplicate]

Described in the title: How do online wallets handle ERC20 tokens behind the scenes? Or centralised exchanges in that matter. Are they simply communicating with the ethereum blockchain to generate ...
2
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0answers
144 views

“data” field is not working in Ethereum QR Code mobile payment

Recently, I am working on generating an Ethereum QR code that mobile wallet (e.g. imToken) can scan and pay from there. But the problem is that I cannot pass the data value. I use C# code to generate ...
1
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2answers
308 views

Can security tokens (ST-20) and utility tokens (ERC-20) exists on same blockchain?

I am trying to build a dApp in which the functionalities of the dApp can be accessed by utility token but in the same app I wish to tokenize the securities as well. Can my utility tokens and the ...
0
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2answers
22 views

How to extract value from hashed output

I am trying to make updates to a standard voting dapp. My aim is to list out voter who has voted for a candidate. So far I have implemented the following: voting.sol: struct voter { bytes32 ...
0
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1answer
315 views

Metamask won't display correct balance after creating customrpc for ganache accounts

I made a customrpc network on metamask using the correct server and imported a private key from ganache, which worked but the eth balance is displaying 0 when I expected it to display 100. According ...
0
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1answer
72 views

miner.start() cannot deploy my contract

My environment: geth 1.8.11 Ethereum Wallet Mist Browser windows 10 I try to deploy a new contract in the Ethereum Wallet. I execute (miner.start();) in the Geth JavaScript console to get some ...
1
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1answer
479 views

web3 and web3 provider engine

Scenario: Import json file and decrypt it Use account to sign the messsage I can do this with web3(Web3.providers.HttpProvider) or with web3-provider-engine. What is major difference between using ...
0
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1answer
30 views

The Token sale contract is returning an exception everytime. Tested on ropsten and there it is working fine

The below is the code for The token: pragma solidity ^0.4.16; interface tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) external; }...
0
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2answers
778 views

Using Ethereum public and private keys to encrypt and decrypt message (metamask client)

I am trying to use Ethereum private and public keys for message encryption like PGP and I found out this npm module on github, https://github.com/pubkey/eth-crypto#encryptwithpublickey, which it lets ...
0
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1answer
222 views

How can we assign unique hash id to the id that created inside our smart contract in ethereum?

I am using truffle, ganache and web3. I am initializing user id in smart contract while deploying the smart contract. As of now, everything is done by account[0] of Ganache. Now, I want functionality ...
1
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1answer
248 views

NodeJS with HDWalletProvider

I want to execute signed Ethereum transactions from a NodeJS program. I am creating a web3_provider like this var contract = require("truffle-contract"); var provider = new HDWalletProvider("nemonic"...
1
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1answer
269 views

Do you know any good code sample of Web3j with Android? [closed]

Do you have any good code sample of Web3j with Android? There is an example in the official docs, but I don't think it is not well self explanatory. I'd like to see an example of wallet generating or ...
0
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2answers
519 views

What are offchain and onchain Transactions?

What is meant by off-chain and on-chain transactions? I don't get the meaning of off-chain and on-chain in general.