BitcoinKeys is a PHP class which can create and handle WIF (Wallet Import Format) private keys and (re)build their related P2PKH (Pay to PubkeyHash) addresses. The class is fully based on the PHP's OpenSSL extension and the class Base58 (included).
P2PKH is the very first Bitcoin address format, starting with 1. The class will also handle private keys in WIF format, beginning with 5, based on the eliptic curve secp256k1 (y² = x³ + 7). Private keys are 32 bytes long (256 bit), beginning from 0x01 to 0xFFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFE BAAE DCE6 AF48 A03B BFD2 5E8C D036 4140. Public keys are 65 bytes long (64 bytes, plus 1 byte prefix 04).
The project also includes the class Base58, which encodes big integers (keys) with human friendly characters, the A to Z letters in both upper and lowercase, the numbers from 1 to 9, without the number "0" (zero), without the uppercase letter O (o), without the lowercase letter l (L) and without the uppercase I (i), since those 4 characters are known to bring confusions and errors in hominids sapiens sapiens.
Private keys must be produced locally and kept in a safe place. Transfer over network may be done through a secure protocol using SSL for instance and private keys, or wallets, should be encrypted thanks to a method like BIP38.
// Initialization
require_once('BitcoinKeys.php');
// Generate a new key
$bk = new BitcoinKeys();
// Print the private key in WIF format
echo "WIF: ".$bk->getWif()."\n";
// Print the address
echo "Addr: ".$bk->getAddress()."\n";
// Import private key in WIF format
$bk = new BitcoinKeys('5Kb8kLf9zgWQnogidDA76MzPL6TsZZY36hWXMssSzNydYXYB9KF');
// Print the private key in hex format
echo "Secret: ".$bk->getSecret()."\n";
// Print the public key in hex format
echo "Public: ".$bk->getPublic()."\n";
// Change network
$bk->setNetwork(BitcoinNetworks::Test);You may also be interested by a bunch of static methods available:
BitcoinKeys::newKeyPair() will return a array with a new randomly generated key pair (private, public), both in hex format.
BitcoinKeys::secretToWif($secret, $network) will build a private key in WIF format from a private key in hex format. Network can be mainnet 80, the default, or testnet ef (hex format).
BitcoinKeys::publicToAddress($public, $network) will build a P2PKH address from a public key in hex format. Network can be mainnet 00, the default, or testnet 6f (hex format).
BitcoinKeys::secretToPem($secret) will return a the private key in PEM format to satisfy OpenSSL, from a private key given in hex format.
BitcoinKeys::wifToKeyPair($wif) will return a key pair (private, public), and the network, in an array, in hex format from a WIF formatted key. Network can be mainnet 00 or testnet 6f (hex format), other values may raise exceptions.
Elliptic-curve keys in basic blockchain programming
Copyright (c) 2021 Alexandre Vialle
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