Sign and check the Bitcoin address in JavaScript
Bitcoin addresses are clear 34-character characters that represent private keys for each Bitcoin letter bag. To check whether a person has a certain Bitcoin address, you must first receive the private key that is assigned to this address. In this article we will examine how a message signed and checked with JavaScript that corresponds to a Bitcoin address.
First steps
At the beginning you have to create a new Bitcoin account or receive the private key of your existing items from an online service such as Electrum, Myether Wallet or Metamask. For the purpose of this example, we assume that we assume that the private key will be saved in our JavaScript code as a JSON -Web -Soken (JWT).
`JavaScript
// Get the private key from an online service
Asynchrical function GetprivateKey () {
Const url = ‘
Const Response = waiting Avetch (URL);
Const Privatey = waiting for an answer. Text ();
return JSON.PARSE (private key);
}
// Check whether we have a certain Bitcoin address with our private key
Function Verifyaddress (address, private approval) {
// convert the private key into a hexadecimal string to maintain easier manipulation
Const Privatyhex = Privatekey.Tostring (16);
// Create a new SHA-256 Hash object
Const hashobject = crypto.createhash (‘Sha256’);
// Update the Hash object with the Bitcoin address and the private key
Hashobject.update (address);
Hashobject.update (private keyhex);
// Get the resulting hexadecimal string of the hash
Const hashex = hashobject.digest (‘hex’);
// Compare the resulting hash with our stored Bitcoin address
return hashex === ‘0000000000 …’; // replace with your actual hash
// helper function for signing messages using ECDSA (digital signature algorithm for elliptical curve)
Function Sign Message (Message, Private Key) {
Const key = crypto.createcdsa ({{{
Namedcurve: ‘Secp256K1’,
Publickey: Private Key,
});
return key.sign (message);
}
// Example use:
Const Message = ‘Hello, Bitcoin!’;
Const Signed Message = Sign Message (Message, GetprivateKey ());
console.log (verifyaddress (signed measurement, getprivatekey ()));
}
`
Signing reports with ECDSA
To sign a message with ECDSA, you must create an RSA or DSA couple with a private key and then use the “Sign measurement” function above. The sample code shows how it works:
`JavaScript
// Create an RSA/ECDSA couple (replace your actual private key).
Const Privatey = GetprivateKey ();
`
As soon as you have signed the message, you can check whether we have this address by checking whether the Hashed Bitcoin address matches our stored hash.
Sign and check messages in JavaScript
Here is a complete example of how to sign and check messages with ECDSA:
`JavaScript
// Get the private key from an online service
Asynchrical function GetprivateKey () {
Const url = ‘
Const Response = waiting Avetch (URL);
Const Privatey = waiting for an answer. Text ();
return JSON.PARSE (private key);
}
// Create a new SHA-256 Hash object
Const Crypto = demands (‘Crypto’);
// helper function for signing messages using ECDSA
Function Sign Message (Message, Private Key) {
// convert the private key into a hexadecimal string to maintain easier manipulation
Const Privatyhex = Privatekey.Tostring (16);
// Create a new SHA-256 Hash object
Const hashobject = crypto.createhash (‘Sha256’);
// Update the Hash object with the Bitcoin address and the private key
Hashobject.update (message);
Hashobject.update (private keyhex);
// Get the resulting hexadecimal string of the hash
Const hashex = hashobject.