web-base/core/Objects/AesStream.class.php
2021-11-11 14:25:32 +01:00

126 lines
3.1 KiB
PHP

<?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;
}
}