[Knowledge] Blockchain Technology [Part 4] – Create virtual currency mining technology

December 29, 2021

Blockchain Technology [Part 4] – Create virtual currency mining technology

Welcome to Learn Tech Tips blog, Today I will continue to share how to create virtual currency mining technology. If you havn’t read part 1, part 2 and part 3, you should view back

In the Block class we add a $no, this is a variable used when calculating the Hash.

// Author: Zidane – Learn Tech Tips,
// Email: huuvi168@gmail.com
class Block
{
    public $time;
    public $data;
    public $previous_hash;
    public $hash;
    public $no;
    public $mining_time_stamp;
    public $start_mining_time;
    public $end_mining_time;
    public function __construct($time, $data, $previous_hash = ”)
    {
        $this->time = $time;
        $this->data = $data;
        $this->previous_hash = $previous_hash;
        $this->hash = $this->calc_hash();
        $this->no = 0;
        $this->mining_time_stamp = 0;
        $this->start_mining_time = 0;
        $this->end_mining_time = 0;
    }
    public function calc_hash()
    {
        $data_content = “”;
        if(is_array($this->data))
        {
            $data_content = json_encode($this->data);
        } else 
        {
            $data_content = $this->data;
        }
        $hash_string = $this->time . $data_content . $this->previous_hash . $this->no;
        return hash(‘sha256’, $hash_string); 
    }
    // mining_block: the core of algorithm mining block
    public function mining_block($nonce) {
        while (substr($this->hash, 0, $nonce) !==  str_pad(”,  $nonce, “0”) ) {
            $this->no++;
            $this->hash = $this->calc_hash();
        }
    }
}

Since we need to increase the difficulty every time the Hash, the calc_hash function remains the same, but we create a simple algorithm, that is, it does not accept the generated Hash code that does not meet the requirements.

Our requirement here is that the Hash code must start with 2 or 3 or 4 or even 5 consecutive “0”.

Since the SHA256 algorithm never changes the output for an input string, it is imperative to change the input string to find a satisfactory output Hash.

Therefore, we write a function called mining_block function to repeat the process of “mining” the Hash code for the current Block.

And this mining difficulty depends on the $nonce variable.

If you increase the number of consecutive 0 digits, it takes a long time to loop to find a satisfactory Hash string.

Example:
$nonce = 2, it takes 0.001s to find a Hash with 2 consecutive zeros at the beginning.

$nonce = 3, it takes 0.5s to find a Hash with 3 consecutive 0s at the beginning.

$nonce = 4, it takes 3s to find a Hash with 4 consecutive 0s at the beginning.

$nonce = 5, it takes 20s to find a Hash with 5 consecutive zeros at the beginning.

For the BitCoin virtual currency, the difficulty of the algorithm is adjusted so that every 10 minutes there will be a Hash code.

Of course, BitCoin’s algorithm is not as simple as the one here. So you already figured it out.

Proof-Of-Work is also abbreviated as PoW.

The PoW concept applied to the Blockchain is similar to the anti-SPAM and DDOS mechanism for a website using ReCapcha, users who want to verify that they are not an automatic robot have to spend time typing a strange string of characters.

// Author: Zidane – Learn Tech Tips,
// Email: huuvi168@gmail.com
class Blockchain extends Block
{
    public $chain = array();
    public $nonce = 0;
    public function __construct()
    {
        $this->chain[] = new Block(time(), “Genesis Block”);
        $this->nonce = 3;
    }
    public function get_latest_item()
    {
        return $this->chain[count($this->chain) – 1];
    }
    public function add_new_block($time, $data)
    {
        $previous_hash = $this->get_latest_item()->hash;
        $block = new Block($time, $data, $previous_hash);
        $start_mining_time  = microtime(true);
        $block->start_mining_time  = gmdate(“Y-m-dTH:i:sZ”,  (int)$start_mining_time);
        $block->mining_block($this->nonce);
        $end_mining_time  = microtime(true);
        $block->end_mining_time  =gmdate(“Y-m-dTH:i:sZ”,  (int)$end_mining_time);
        $mining_time_stamp = $end_mining_time * 1000 – $start_mining_time * 1000;
        $block->mining_time_stamp  = $mining_time_stamp;
        $this->chain[] = $block;   
    }
    public function validate()
    {
        for ($i = 1; $i < count($this->chain); $i++) {
            $current_block = $this->chain[$i];
            $previous_block = $this->chain[$i – 1];
            if ($current_block->hash != $current_block->calc_hash()) {
                return false;
            }
            if ($current_block->previous_hash != $previous_block->hash) {
                return false;
            }
            return true;
        }
    }
}

We need to create a variable $nonce in the Blockchain.

Then we call $block->mining_block($this->nonce); so that every time we create a new Block (add_new_block function), we have to dig a new Hash code for it.

Leave your comment if you need discuss anything about Blockchain technology

Learn Tech Tips – Zidane

Full source code you can checkout here – BlockchainsControllers_v2.php

Related Posts:

Blockchain Part 1: What is Blockchain: https://learn-tech-tips.blogspot.com/2021/12/what-is-blockchain.html

Blockchain Part 2: Using PHP develop Blockchain Technology: https://learn-tech-tips.blogspot.com/2021/12/using-php-develop-blockchain-technology.html

Blockchain Part 3: Loophples of the current Blockchain:

https://learn-tech-tips.blogspot.com/2021/12/loophples-of-the-current-blockchain.html

Blockchain Part 4: Create virtual currency mining technology:

https://learn-tech-tips.blogspot.com/2021/12/blockchain-technology-create-virtual-currency-mining-technology.html

Blockchain Part 5: How to create own bitcoin virtual currency

https://learn-tech-tips.blogspot.com/2021/12/blockchain-technology-how-to-create-own-bitcoin-virtual-currency.html