public function sign_transaction($transaction, $inputs)
{
// Initialize
$bip32 = new bip32();
// Start transaction
$transaction[] = '01000000';
$orig_transaction = $transaction;
// Add inputs temporarily
$temp_input = 3;
foreach ($inputs as $input) {
// Set transaction variables
$temp_transaction = $orig_transaction;
if (count($input['privkeys']) > 1) {
$temp_transaction[$temp_input] = $this->encode_vint(strlen(hex2bin($input['scriptsig'])));
$temp_transaction[$temp_input + 1] = $input['scriptsig'];
} else {
$temp_transaction[$temp_input] = dechex(strlen(hex2bin($input['scriptsig'])));
$temp_transaction[$temp_input + 1] = $input['scriptsig'];
}
// Initialize
$generator = SECcurve::generator_secp256k1();
// Hash structure
$temp_hex_trans = pack("H*", implode("", $temp_transaction));
$hash = hash('sha256', hash('sha256', $temp_hex_trans, true));
// Go through the keys
$signatures = array();
$total_sign = 0;
foreach ($input['privkeys'] as $privkey) {
// Get public key
$import = $bip32->import($privkey);
$pubkey = $bip32->private_to_public($import['key']);
$cpubkey = $bip32->private_to_public($import['key'], true);
// Get ready to sign
$point = new Point($generator->getCurve(), gmp_init(substr($pubkey, 2, 64), 16), gmp_init(substr($pubkey, 66, 64), 16), $generator->getOrder());
$_public_key = new PublicKey($generator, $point);
$_private_key = new PrivateKey($_public_key, gmp_init($import['key'], 16));
// Sign
$sign = $_private_key->sign(gmp_init($hash, 16), gmp_init((string) bin2hex(openssl_random_pseudo_bytes(32)), 16));
$signatures[$cpubkey] = $this->_encode_signature($sign);
$total_sign++;
}
// Encode signature
if (count($input['privkeys']) > 1) {
$sig = '00';
foreach ($signatures as $pubkey => $sign) {
$sig .= $this->encode_vint(strlen($sign) / 2) . $sign;
}
$sig .= '4c' . $this->encode_vint(strlen($input['scriptsig']) / 2) . $input['scriptsig'];
} else {
$key = array_keys($signatures)[0];
$sig = $this->encode_vint(strlen($signatures[$key]) / 2) . $signatures[$key];
$sig .= $this->encode_vint(strlen($key) / 2) . $key;
}
// Add to transaction
$transaction[$temp_input] = $this->encode_vint(strlen(hex2bin($sig)));
$transaction[$temp_input + 1] = $sig;
$temp_input += 4;
}
array_pop($transaction);
// Return
return implode("", $transaction);
}
