1.3.0

core/Objects/AesStream.class.php

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