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<?php |
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/** |
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* This file is part of the O2System Framework package. |
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* |
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* For the full copyright and license information, please view the LICENSE |
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* file that was distributed with this source code. |
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* |
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* @author Steeve Andrian Salim |
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* @copyright Copyright (c) Steeve Andrian Salim |
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*/ |
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// ------------------------------------------------------------------------ |
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namespace O2System\Security\Blockchain; |
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// ------------------------------------------------------------------------ |
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use O2System\Security\Generators\Uuid; |
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use O2System\Spl\Iterators\ArrayIterator; |
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/** |
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* Class Chain |
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* @package O2System\Security\Blockchain |
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*/ |
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class Chain extends ArrayIterator |
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{ |
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/** |
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* Chain::$difficulty |
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* |
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* @var int |
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*/ |
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protected $difficulty; |
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// ------------------------------------------------------------------------ |
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/** |
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* Chain::__construct |
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* |
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* @param int $difficulty |
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*/ |
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public function __construct($difficulty = 4) |
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{ |
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parent::__construct(); |
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$this->difficulty = $difficulty; |
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// Creating Genesis Block |
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$this->addBlock(new Block(0, strtotime("now"), 'GENESIS_BLOCK ' . Uuid::generate())); |
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} |
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// ------------------------------------------------------------------------ |
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/** |
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* Chain::addBlock |
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* |
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* @param \O2System\Security\Blockchain\Block $block |
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*/ |
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public function addBlock(Block $block) |
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{ |
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if ($this->count()) { |
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$lastBlock = $this->last(); |
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if ($lastBlock instanceof Block) { |
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$block->setPreviousHash($lastBlock->getHash()); |
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$this->mine($block); |
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$this->push($block); |
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} |
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} else { |
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$this->push($block); |
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} |
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} |
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// ------------------------------------------------------------------------ |
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/** |
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* Chain::mine |
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* |
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* @param \O2System\Security\Blockchain\Block $block |
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*/ |
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public function mine(Block $block) |
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{ |
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while (substr($block->getHash(), 0, $this->difficulty) !== str_repeat('0', $this->difficulty)) { |
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$block->regenerateHash(); |
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} |
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} |
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// ------------------------------------------------------------------------ |
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/** |
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* Chain::isValid |
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* |
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* Validates the blockchain's integrity. |
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* |
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* @return bool Returns FALSE if the blockchain integrity is invalid. |
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*/ |
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public function isValid() |
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{ |
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for ($i = 1; $i < $this->count(); $i++) { |
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$currentBlock = $this->offsetGet($i); |
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$previousBlock = $this->offsetGet($i - 1); |
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if ($currentBlock instanceof Block) { |
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if ($currentBlock->getHash() != $currentBlock->calculateHash()) { |
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return false; |
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} |
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if ($previousBlock instanceof Block) { |
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if ($currentBlock->getPreviousHash() != $previousBlock->getHash()) { |
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return false; |
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} |
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} |
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} |
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} |
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return true; |
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} |
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} |
o2system /
security
