Category "blockchain"

How to get all transaction from an address via the etherscan API in R?

I've been looking for a way to download all transaction from a specific contract since their start up until now. It's around 25k transactions as of today. I've

How to call a smart contract function with WalletConnect? (React.js, Node.js)

Is it actually possible to call a smart contract function using WalletConnect? There is a documentation on official website that explains how to establish conne

Restrict function access ONLY to one other specific contract in Solidity

I have a security problem in my Solidity contracts and I can't figure out how to fix it. The flow goes like this: First, we create an instance of contract A; Cr

How can I build a bitcoin wallet?

I am going to work on a project in which we want to build a bitcoin wallet, like for example mycelium, coinbase etc, but I have no knowledge of which apis we sh

error[E0412]: cannot find type `ProgramResult` in this scope

use anchor_lang::prelude::*; declare_id!("Fg6PaFpoGXkYsidMpWTK6W2BeZ7FEfcYkg476zPFsLnS"); #[program] pub mod myepicproject { use super::*; pub fn start_st

How to get query transaction id from AWS managed blockchain using chaincode

I am not able to get transaction id from AWS managed blockchain using chaincode's stub.getState(key) method. Please suggest..

I want to get the address from mnemonic with the proper derivation path

I am very new to blockchain programming and programming in general. I want to generate my SOL address using the mnemonic seed phrase with the derivation path "m

Error: TypeError [ERR_INVALID_REPL_INPUT]: Listeners for `uncaughtException` cannot be used in the REPL at Object.compile

I am new to truffle and I work on blockchain project so when I "migrate" in truffle develop, this error occurs. Why ? I change the version of my compiler by 4.2

Paying with ERC20 token

I want to build an NFT that I can paid with an ERC-20 token to mint it. I'm using currently the Mumbai testnet on polygon, and I'm using the Dummy ERC20 token t

can I access the private key of solana account (via phantom) to encrypt data?

I am very new to web3 etc but as far as I know, every account is represented by a public/private key. The public key can be accessed anytime and the private key

What is the Unexpected Token syntax error in line six?

I'm trying to learn how to create NFTs on the Ethereum block chain. In terminal (Ubuntu 20.04.3 LTS) Aki-Zeta:~/my-nft$ node scripts/mint-nft.js I keep getting

Can't Retrieve Wallets transactions using web3

so yea I tried to get all the transactions of a wallet address on a certain token contract. But it keeps on returning null. const Web3 = require('web3') const

i am working on supply chain DApps .here i want to add budget with ownername only not with the whole block

type Product struct { ID string `json:"id"` Name string `json:"name"` Area string `json:"area"` OwnerName string `json:"own

Where do I store metadata of NFT

Smart contract execution needs gas fee. So all data can't be stored in blockchain. Images could be stored on ipfs like Pinata. Do I have to develop extra backen

Airdropping Solana to a Specific Account

I would like to airdrop sols into a specific account to get my smart contract to fire an anchor test. Whenever I run my test I come across the error Error: Acco

Error: Custom: Invalid blockhash when solana program deploy

Trying to deploy a program to solana devnet. I was using solana program deploy ./path/xxxx.so -u devnet And I got multiple lines of msg 21AbKBwMcsDR4DciR6Z69X6v

Can smart contracts deploy other smart contracts?

If a smart contract has the compiled bytecode for a contract can the first deploy a subsequent contract? According to Ethereum.org: "To deploy a smart contract,

Hyperledger Blockchain Explorer-Fail to connect before the deadline on Endorser, fail to connect to remote gRPC server

I am trying to set up a Hyperledger Fabric Network with Hyperledger Explorer. I spin up a VM on the digital ocean cloud with ubuntu OS. From there, I spin up 3

In Corda flow tests, how to get the modularized cordapps assigned only to the respective parties?

As per the Corda coding guidelines, I have seperated out modules into contracts and workflows-common. There are workflows modules like workflows-party1, workflo

RocksDb: Multiple values per key (c++)

RocksDb: Multiple values per key (c++) what i am trying to do I am trying to adapt my simple blockchain implementation to save the blockchain to the hard drive