Андрей

<?php
function encrypt_data($key, $text){
  $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
  $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
  $encrypted_text = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $key, $text, MCRYPT_MODE_ECB, $iv);
  return $encrypted_text;
}

function decrypt_data($key, $text){
  global $encryptionkey;
  $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
  $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
  $decrypted_text = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $key, $text, MCRYPT_MODE_ECB, $iv);
  return $decrypted_text;
}

$key = 'This is a very secret key';
$text = "Meet me at 11 o'clock behind the monument.";
echo $text .':'. mb_strlen ($text)."\n";

$crypttext = encrypt_data ($key,$text);

$decrypttext = decrypt_data ($key, $crypttext) ;
echo  $decrypttext.':'. mb_strlen ($decrypttext)."\n";
var_dump($decrypttext);

[AGvin@localhost public]$ php test.php 
Meet me at 11 o'clock behind the monument.:42
Meet me at 11 o'clock behind the monument.:64
string(64) "Meet me at 11 o'clock behind the monument.\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"

<?php
function decrypt_data($key, $text){
  global $encryptionkey;
  $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
  $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
  $decrypted_text = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $key, $text, MCRYPT_MODE_ECB, $iv);
  return rtrim($decrypted_text, '\0');;
}

$(function() {
  $.ajax({
    url : 'kp.php',
    data : {
      imageURL : 'http://st.kinopoisk.ru/images/film_big/602829.jpg'
    }
  }).done(function(img) {
    $('body').append('<img src="' + img + '" />');
  })
})

<?php

$url = $_GET['imageURL'];
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_REFERER, "");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$result = curl_exec($ch);
curl_close($ch);

echo 'data:image/jpeg;base64,' . base64_encode($result);

?>