126 lines
3.1 KiB
PHP
126 lines
3.1 KiB
PHP
<?php
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namespace Objects;
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class AesStream {
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private string $key;
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private string $iv;
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private $callback;
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private ?string $outputFile;
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private ?string $inputFile;
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public function __construct(string $key, string $iv) {
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$this->key = $key;
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$this->iv = $iv;
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$this->inputFile = null;
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$this->outputFile = null;
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$this->callback = null;
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if (!in_array(strlen($key), [16, 24, 32])) {
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throw new \Exception("Invalid Key Size");
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} else if (strlen($iv) !== 16) {
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throw new \Exception("Invalid IV Size");
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}
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}
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public function setInput($file) {
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$this->inputFile = $file;
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}
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public function setOutput($callback) {
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$this->callback = $callback;
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}
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public function setOutputFile(string $file) {
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$this->outputFile = $file;
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}
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private function add(string $a, int $b): string {
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// counter $b is n = PHP_INT_SIZE bytes large
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$b_arr = pack('I', $b);
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$b_size = strlen($b_arr);
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$a_size = strlen($a);
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$prefix = "";
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if ($a_size > $b_size) {
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$prefix = substr($a, 0, $a_size - $b_size);
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}
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// xor last n bytes of $a with $b
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$xor = substr($a, strlen($prefix), $b_size);
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if (strlen($xor) !== strlen($b_arr)) {
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var_dump($xor);
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var_dump($b_arr);
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die();
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}
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$xor = $this->xor($xor, $b_arr);
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return $prefix . $xor;
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}
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private function xor(string $a, string $b): string {
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$arr_a = str_split($a);
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$arr_b = str_split($b);
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if (strlen($a) !== strlen($b)) {
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var_dump($a);
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var_dump($b);
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var_dump(range(0, strlen($a) - 1));
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die();
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}
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return implode("", array_map(function($i) use ($arr_a, $arr_b) {
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return chr(ord($arr_a[$i]) ^ ord($arr_b[$i]));
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}, range(0, strlen($a) - 1)));
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}
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public function start(): bool {
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if (!$this->inputFile) {
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return false;
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}
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$blockSize = 16;
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$bitStrength = strlen($this->key) * 8;
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$aesMode = "AES-$bitStrength-ECB";
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$outputHandle = null;
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$inputHandle = fopen($this->inputFile, "rb");
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if (!$inputHandle) {
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return false;
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}
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if ($this->outputFile !== null) {
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$outputHandle = fopen($this->outputFile, "wb");
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if (!$outputHandle) {
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return false;
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}
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}
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$counter = 0;
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while (!feof($inputHandle)) {
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$chunk = fread($inputHandle, 4096);
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$chunkSize = strlen($chunk);
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for ($offset = 0; $offset < $chunkSize; $offset += $blockSize) {
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$block = substr($chunk, $offset, $blockSize);
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if (strlen($block) !== $blockSize) {
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$padding = ($blockSize - strlen($block));
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$block .= str_repeat(chr($padding), $padding);
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}
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$ivCounter = $this->add($this->iv, $counter + 1);
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$encrypted = substr(openssl_encrypt($ivCounter, $aesMode, $this->key, OPENSSL_RAW_DATA), 0, $blockSize);
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$encrypted = $this->xor($encrypted, $block);
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if (is_callable($this->callback)) {
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call_user_func($this->callback, $encrypted);
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}
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if ($outputHandle !== null) {
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fwrite($outputHandle, $encrypted);
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}
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}
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}
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fclose($inputHandle);
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if ($outputHandle) fclose($outputHandle);
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return true;
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}
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} |