Files
node/include/block.inc.php

653 lines
20 KiB
PHP
Executable File

<?php
class Block
{
public function add($height, $public_key, $nonce, $data, $date, $signature, $difficulty, $reward_signature, $argon)
{
global $db;
$acc = new Account();
$trx = new Transaction();
$generator = $acc->get_address($public_key);
// the transactions are always sorted in the same way, on all nodes, as they are hashed as json
ksort($data);
// create the hash / block id
$hash = $this->hash($generator, $height, $date, $nonce, $data, $signature, $difficulty, $argon);
//fix for the broken base58 library used until block 16900, trimming the first 0 bytes.
if ($height < 16900) {
$hash = ltrim($hash, '1');
}
$json = json_encode($data);
// create the block data and check it against the signature
$info = "{$generator}-{$height}-{$date}-{$nonce}-{$json}-{$difficulty}-{$argon}";
if (!$acc->check_signature($info, $signature, $public_key)) {
_log("Block signature check failed");
return false;
}
if (!$this->parse_block($hash, $height, $data, true)) {
_log("Parse block failed");
return false;
}
// lock table to avoid race conditions on blocks
$db->exec("LOCK TABLES blocks WRITE, accounts WRITE, transactions WRITE, mempool WRITE");
$reward = $this->reward($height, $data);
$msg = '';
// the reward transaction
$transaction = [
"src" => $generator,
"dst" => $generator,
"val" => $reward,
"version" => 0,
"date" => $date,
"message" => $msg,
"fee" => "0.00000000",
"public_key" => $public_key,
];
$transaction['signature'] = $reward_signature;
// hash the transaction
$transaction['id'] = $trx->hash($transaction);
// check the signature
$info = $transaction['val']."-".$transaction['fee']."-".$transaction['dst']."-".$transaction['message']."-".$transaction['version']."-".$transaction['public_key']."-".$transaction['date'];
if (!$acc->check_signature($info, $reward_signature, $public_key)) {
_log("Reward signature failed");
return false;
}
// insert the block into the db
$db->beginTransaction();
$total = count($data);
$bind = [
":id" => $hash,
":generator" => $generator,
":signature" => $signature,
":height" => $height,
":date" => $date,
":nonce" => $nonce,
":difficulty" => $difficulty,
":argon" => $argon,
":transactions" => $total,
];
$res = $db->run(
"INSERT into blocks SET id=:id, generator=:generator, height=:height,`date`=:date,nonce=:nonce, signature=:signature, difficulty=:difficulty, argon=:argon, transactions=:transactions",
$bind
);
if ($res != 1) {
// rollback and exit if it fails
_log("Block DB insert failed");
$db->rollback();
$db->exec("UNLOCK TABLES");
return false;
}
// insert the reward transaction in the db
$trx->add($hash, $height, $transaction);
// parse the block's transactions and insert them to db
$res = $this->parse_block($hash, $height, $data, false);
// if any fails, rollback
if ($res == false) {
$db->rollback();
} else {
$db->commit();
}
// relese the locking as everything is finished
$db->exec("UNLOCK TABLES");
return true;
}
// returns the current block, without the transactions
public function current()
{
global $db;
$current = $db->row("SELECT * FROM blocks ORDER by height DESC LIMIT 1");
if (!$current) {
$this->genesis();
return $this->current(true);
}
return $current;
}
// returns the previous block
public function prev()
{
global $db;
$current = $db->row("SELECT * FROM blocks ORDER by height DESC LIMIT 1,1");
return $current;
}
// calculates the difficulty / base target for a specific block. The higher the difficulty number, the easier it is to win a block.
public function difficulty($height = 0)
{
global $db;
// if no block height is specified, use the current block.
if ($height == 0) {
$current = $this->current();
} else {
$current = $this->get($height);
}
$height = $current['height'];
if ($height == 10801) {
return 5555555555; //hard fork 10900 resistance, force new difficulty
}
// last 20 blocks used to check the block times
$limit = 20;
if ($height < 20) {
$limit = $height - 1;
}
// for the first 10 blocks, use the genesis difficulty
if ($height < 10) {
return $current['difficulty'];
}
// elapsed time between the last 20 blocks
$first = $db->row("SELECT `date` FROM blocks ORDER by height DESC LIMIT $limit,1");
$time = $current['date'] - $first['date'];
// avg block time
$result = ceil($time / $limit);
// if larger than 200 sec, increase by 5%
if ($result > 220) {
$dif = bcmul($current['difficulty'], 1.05);
} elseif ($result < 260) {
// if lower, decrease by 5%
$dif = bcmul($current['difficulty'], 0.95);
} else {
// keep current difficulty
$dif = $current['difficulty'];
}
if (strpos($dif, '.') !== false) {
$dif = substr($dif, 0, strpos($dif, '.'));
}
//minimum and maximum diff
if ($dif < 1000) {
$dif = 1000;
}
if ($dif > 9223372036854775800) {
$dif = 9223372036854775800;
}
return $dif;
}
// calculates the maximum block size and increase by 10% the number of transactions if > 100 on the last 100 blocks
public function max_transactions()
{
global $db;
$current = $this->current();
$limit = $current['height'] - 100;
$avg = $db->single("SELECT AVG(transactions) FROM blocks WHERE height>:limit", [":limit" => $limit]);
if ($avg < 100) {
return 100;
}
return ceil($avg * 1.1);
}
// calculate the reward for each block
public function reward($id, $data = [])
{
// starting reward
$reward = 1000;
// decrease by 1% each 10800 blocks (approx 1 month)
$factor = floor($id / 10800) / 100;
$reward -= $reward * $factor;
if ($reward < 0) {
$reward = 0;
}
// calculate the transaction fees
$fees = 0;
if (count($data) > 0) {
foreach ($data as $x) {
$fees += $x['fee'];
}
}
return number_format($reward + $fees, 8, '.', '');
}
// checks the validity of a block
public function check($data)
{
// argon must have at least 20 chars
if (strlen($data['argon']) < 20) {
_log("Invalid block argon - $data[argon]");
return false;
}
$acc = new Account();
// generator's public key must be valid
if (!$acc->valid_key($data['public_key'])) {
_log("Invalid public key - $data[public_key]");
return false;
}
//difficulty should be the same as our calculation
if ($data['difficulty'] != $this->difficulty()) {
_log("Invalid difficulty - $data[difficulty] - ".$this->difficulty());
return false;
}
//check the argon hash and the nonce to produce a valid block
if (!$this->mine($data['public_key'], $data['nonce'], $data['argon'])) {
_log("Mine check failed");
return false;
}
return true;
}
// creates a new block on this node
public function forge($nonce, $argon, $public_key, $private_key)
{
//check the argon hash and the nonce to produce a valid block
if (!$this->mine($public_key, $nonce, $argon)) {
_log("Forge failed - Invalid argon");
return false;
}
// the block's date timestamp must be bigger than the last block
$current = $this->current();
$height = $current['height'] += 1;
$date = time();
if ($date <= $current['date']) {
_log("Forge failed - Date older than last block");
return false;
}
// get the mempool transactions
$txn = new Transaction();
$data = $txn->mempool($this->max_transactions());
$difficulty = $this->difficulty();
$acc = new Account();
$generator = $acc->get_address($public_key);
// always sort the transactions in the same way
ksort($data);
// sign the block
$signature = $this->sign($generator, $height, $date, $nonce, $data, $private_key, $difficulty, $argon);
// reward transaction and signature
$reward = $this->reward($height, $data);
$msg = '';
$transaction = [
"src" => $generator,
"dst" => $generator,
"val" => $reward,
"version" => 0,
"date" => $date,
"message" => $msg,
"fee" => "0.00000000",
"public_key" => $public_key,
];
ksort($transaction);
$reward_signature = $txn->sign($transaction, $private_key);
// add the block to the blockchain
$res = $this->add(
$height,
$public_key,
$nonce,
$data,
$date,
$signature,
$difficulty,
$reward_signature,
$argon
);
if (!$res) {
_log("Forge failed - Block->Add() failed");
return false;
}
return true;
}
// check if the arguments are good for mining a specific block
public function mine($public_key, $nonce, $argon, $difficulty = 0, $current_id = 0, $current_height = 0)
{
global $_config;
// if no id is specified, we use the current
if ($current_id === 0) {
$current = $this->current();
$current_id = $current['id'];
$current_height = $current['height'];
}
// get the current difficulty if empty
if ($difficulty === 0) {
$difficulty = $this->difficulty();
}
// the argon parameters are hardcoded to avoid any exploits
if ($current_height > 10800) {
$argon = '$argon2i$v=19$m=524288,t=1,p=1'.$argon; //10800 block hard fork - resistance against gpu
} else {
$argon = '$argon2i$v=19$m=16384,t=4,p=4'.$argon;
}
// the hash base for agon
$base = "$public_key-$nonce-".$current_id."-$difficulty";
// check argon's hash validity
if (!password_verify($base, $argon)) {
return false;
}
// all nonces are valid in testnet
if ($_config['testnet'] == true) {
return true;
}
// prepare the base for the hashing
$hash = $base.$argon;
// hash the base 6 times
for ($i = 0; $i < 5;
$i++) {
$hash = hash("sha512", $hash, true);
}
$hash = hash("sha512", $hash);
// split it in 2 char substrings, to be used as hex
$m = str_split($hash, 2);
// calculate a number based on 8 hex numbers - no specific reason, we just needed an algoritm to generate the number from the hash
$duration = hexdec($m[10]).hexdec($m[15]).hexdec($m[20]).hexdec($m[23]).hexdec($m[31]).hexdec($m[40]).hexdec($m[45]).hexdec($m[55]);
// the number must not start with 0
$duration = ltrim($duration, '0');
// divide the number by the difficulty and create the deadline
$result = gmp_div($duration, $difficulty);
// if the deadline >0 and <=240, the arguments are valid fora block win
if ($result > 0 && $result <= 240) {
return true;
}
return false;
}
// parse the block transactions
public function parse_block($block, $height, $data, $test = true)
{
global $db;
// data must be array
if ($data === false) {
return false;
}
$acc = new Account();
$trx = new Transaction();
// no transactions means all are valid
if (count($data) == 0) {
return true;
}
// check if the number of transactions is not bigger than current block size
$max = $this->max_transactions();
if (count($data) > $max) {
return false;
}
$balance = [];
foreach ($data as &$x) {
// get the sender's account if empty
if (empty($x['src'])) {
$x['src'] = $acc->get_address($x['public_key']);
}
//validate the transaction
if (!$trx->check($x, $height)) {
return false;
}
// prepare total balance
$balance[$x['src']] += $x['val'] + $x['fee'];
// check if the transaction is already on the blockchain
if ($db->single("SELECT COUNT(1) FROM transactions WHERE id=:id", [":id" => $x['id']]) > 0) {
return false;
}
}
// check if the account has enough balance to perform the transaction
foreach ($balance as $id => $bal) {
$res = $db->single(
"SELECT COUNT(1) FROM accounts WHERE id=:id AND balance>=:balance",
[":id" => $id, ":balance" => $bal]
);
if ($res == 0) {
return false; // not enough balance for the transactions
}
}
// if the test argument is false, add the transactions to the blockchain
if ($test == false) {
foreach ($data as $d) {
$res = $trx->add($block, $height, $d);
if ($res == false) {
return false;
}
}
}
return true;
}
// initialize the blockchain, add the genesis block
private function genesis()
{
global $db;
$signature = 'AN1rKvtLTWvZorbiiNk5TBYXLgxiLakra2byFef9qoz1bmRzhQheRtiWivfGSwP6r8qHJGrf8uBeKjNZP1GZvsdKUVVN2XQoL';
$generator = '2P67zUANj7NRKTruQ8nJRHNdKMroY6gLw4NjptTVmYk6Hh1QPYzzfEa9z4gv8qJhuhCNM8p9GDAEDqGUU1awaLW6';
$public_key = 'PZ8Tyr4Nx8MHsRAGMpZmZ6TWY63dXWSCyjGMdVDanywM3CbqvswVqysqU8XS87FcjpqNijtpRSSQ36WexRDv3rJL5X8qpGvzvznuErSRMfb2G6aNoiaT3aEJ';
$reward_signature = '381yXZ3yq2AXHHdXfEm8TDHS4xJ6nkV4suXtUUvLjtvuyi17jCujtwcwXuYALM1F3Wiae2A4yJ6pXL1kTHJxZbrJNgtsKEsb';
$argon = '$M1ZpVzYzSUxYVFp6cXEwWA$CA6p39MVX7bvdXdIIRMnJuelqequanFfvcxzQjlmiik';
$difficulty = "5555555555";
$height = 1;
$data = [];
$date = '1515324995';
$nonce = '4QRKTSJ+i9Gf9ubPo487eSi+eWOnIBt9w4Y+5J+qbh8=';
$res = $this->add(
$height,
$public_key,
$nonce,
$data,
$date,
$signature,
$difficulty,
$reward_signature,
$argon
);
if (!$res) {
api_err("Could not add the genesis block.");
}
}
// delete last X blocks
public function pop($no = 1)
{
$current = $this->current();
$this->delete($current['height'] - $no + 1);
}
// delete all blocks >= height
public function delete($height)
{
if ($height < 2) {
$height = 2;
}
global $db;
$trx = new Transaction();
$r = $db->run("SELECT * FROM blocks WHERE height>=:height ORDER by height DESC", [":height" => $height]);
if (count($r) == 0) {
return;
}
$db->beginTransaction();
$db->exec("LOCK TABLES blocks WRITE, accounts WRITE, transactions WRITE, mempool WRITE");
foreach ($r as $x) {
$res = $trx->reverse($x['id']);
if ($res === false) {
$db->rollback();
$db->exec("UNLOCK TABLES");
return false;
}
$res = $db->run("DELETE FROM blocks WHERE id=:id", [":id" => $x['id']]);
if ($res != 1) {
$db->rollback();
$db->exec("UNLOCK TABLES");
return false;
}
}
$db->commit();
$db->exec("UNLOCK TABLES");
return true;
}
// delete specific block
public function delete_id($id)
{
global $db;
$trx = new Transaction();
$x = $db->row("SELECT * FROM blocks WHERE id=:id", [":id" => $id]);
if ($x === false) {
return false;
}
// avoid race conditions on blockchain manipulations
$db->beginTransaction();
$db->exec("LOCK TABLES blocks WRITE, accounts WRITE, transactions WRITE, mempool WRITE");
// reverse all transactions of the block
$res = $trx->reverse($x['id']);
if ($res === false) {
// rollback if you can't reverse the transactions
$db->rollback();
$db->exec("UNLOCK TABLES");
return false;
}
// remove the actual block
$res = $db->run("DELETE FROM blocks WHERE id=:id", [":id" => $x['id']]);
if ($res != 1) {
//rollback if you can't delete the block
$db->rollback();
$db->exec("UNLOCK TABLES");
return false;
}
// commit and release if all good
$db->commit();
$db->exec("UNLOCK TABLES");
return true;
}
// sign a new block, used when mining
public function sign($generator, $height, $date, $nonce, $data, $key, $difficulty, $argon)
{
$json = json_encode($data);
$info = "{$generator}-{$height}-{$date}-{$nonce}-{$json}-{$difficulty}-{$argon}";
$signature = ec_sign($info, $key);
return $signature;
}
// generate the sha512 hash of the block data and converts it to base58
public function hash($public_key, $height, $date, $nonce, $data, $signature, $difficulty, $argon)
{
$json = json_encode($data);
$hash = hash("sha512", "{$public_key}-{$height}-{$date}-{$nonce}-{$json}-{$signature}-{$difficulty}-{$argon}");
return hex2coin($hash);
}
// exports the block data, to be used when submitting to other peers
public function export($id = "", $height = "")
{
if (empty($id) && empty($height)) {
return false;
}
global $db;
$trx = new Transaction();
if (!empty($height)) {
$block = $db->row("SELECT * FROM blocks WHERE height=:height", [":height" => $height]);
} else {
$block = $db->row("SELECT * FROM blocks WHERE id=:id", [":id" => $id]);
}
if (!$block) {
return false;
}
$r = $db->run("SELECT * FROM transactions WHERE version>0 AND block=:block", [":block" => $block['id']]);
$transactions = [];
foreach ($r as $x) {
$trans = [
"id" => $x['id'],
"dst" => $x['dst'],
"val" => $x['val'],
"fee" => $x['fee'],
"signature" => $x['signature'],
"message" => $x['message'],
"version" => $x['version'],
"date" => $x['date'],
"public_key" => $x['public_key'],
];
ksort($trans);
$transactions[$x['id']] = $trans;
}
ksort($transactions);
$block['data'] = $transactions;
// the reward transaction always has version 0
$gen = $db->row(
"SELECT public_key, signature FROM transactions WHERE version=0 AND block=:block",
[":block" => $block['id']]
);
$block['public_key'] = $gen['public_key'];
$block['reward_signature'] = $gen['signature'];
return $block;
}
//return a specific block as array
public function get($height)
{
global $db;
if (empty($height)) {
return false;
}
$block = $db->row("SELECT * FROM blocks WHERE height=:height", [":height" => $height]);
return $block;
}
}