diff --git a/bootstrap.php b/bootstrap.php
index de4cbfb6..f5cbeeff 100644
--- a/bootstrap.php
+++ b/bootstrap.php
@@ -2,5 +2,4 @@
 
 define('ROOT_DIR', __DIR__);
 date_default_timezone_set('Etc/UTC');
-
-include ROOT_DIR . '/autoload.php';
+require ROOT_DIR . '/autoload.php';
\ No newline at end of file
diff --git a/controller/action/DownloadActions.class.php b/controller/action/DownloadActions.class.php
index afda9134..fe17cf71 100644
--- a/controller/action/DownloadActions.class.php
+++ b/controller/action/DownloadActions.class.php
@@ -25,7 +25,7 @@ class DownloadActions extends Actions
 
   public static function executeGetDaemonRedirect(string $os)
   {
-    $uri = null;
+    $uri  = null;
     $oses = Os::getAll();
 
     if (isset($oses[$os]))
@@ -38,8 +38,8 @@ class DownloadActions extends Actions
 
   public static function executeGet()
   {
-    $email = Request::getParam('e');
-    $user = [];
+    $email = static::getEmailParam();
+    $user  = [];
 
     if ($email)
     {
@@ -147,7 +147,7 @@ class DownloadActions extends Actions
   public static function prepareSignupPartial(array $vars)
   {
     return $vars + [
-      'defaultEmail'    => Request::getParam('e'),
+      'defaultEmail'    => static::getEmailParam(),
       'allowInviteCode' => true,
       'referralCode'    => Request::getParam('r', '')
     ];
@@ -209,4 +209,24 @@ class DownloadActions extends Actions
       return OS::OS_WINDOWS;
     }
   }
+
+  protected static function getEmailParam()
+  {
+    $email = Request::getParam('e');
+
+    if (!$email)
+    {
+      $encoded = Request::getParam('ec');
+      if ($encoded)
+      {
+        $email = Smaz::decode(Encoding::base64DecodeUrlsafe($encoded), Smaz::CODEBOOK_EMAIL);
+        if (!filter_var($email, FILTER_VALIDATE_EMAIL))
+        {
+          $email = null;
+        }
+      }
+    }
+
+    return $email;
+  }
 }
diff --git a/lib/tools/Smaz.class.php b/lib/tools/Smaz.class.php
new file mode 100644
index 00000000..c27b7bee
--- /dev/null
+++ b/lib/tools/Smaz.class.php
@@ -0,0 +1,211 @@
+<?php
+
+/**
+ * SMAZ - compression for very small strings
+ *
+ * https://github.com/zhenhao/smaz.php (PHP port of https://github.com/antirez/smaz)
+ *
+ * <pre>Smaz is a simple compression library for compressing very short
+ * strings. General purpose compression libraries will build the state needed
+ * for compressing data dynamically, in order to be able to compress every kind
+ * of data. This is a very good idea, but not for a specific problem: compressing
+ * small strings will not work.</pre>
+ */
+class Smaz
+{
+  const CODEBOOK_DEFAULT = 'default';
+  const CODEBOOK_EMAIL   = 'email';
+
+  const VERBATIM_CHAR = 254;
+  const VERBATIM_STR  = 255;
+
+  protected static $encodeBooks = [];
+  protected static $decodeBooks = [
+    self::CODEBOOK_DEFAULT => [
+      " ", "the", "e", "t", "a", "of", "o", "and", "i", "n", "s", "e ", "r", " th",
+      " t", "in", "he", "th", "h", "he ", "to", "\r\n", "l", "s ", "d", " a", "an",
+      "er", "c", " o", "d ", "on", " of", "re", "of ", "t ", ", ", "is", "u", "at",
+      "   ", "n ", "or", "which", "f", "m", "as", "it", "that", "\n", "was", "en",
+      "  ", " w", "es", " an", " i", "\r", "f ", "g", "p", "nd", " s", "nd ", "ed ",
+      "w", "ed", "http://", "for", "te", "ing", "y ", "The", " c", "ti", "r ", "his",
+      "st", " in", "ar", "nt", ",", " to", "y", "ng", " h", "with", "le", "al", "to ",
+      "b", "ou", "be", "were", " b", "se", "o ", "ent", "ha", "ng ", "their", "\"",
+      "hi", "from", " f", "in ", "de", "ion", "me", "v", ".", "ve", "all", "re ",
+      "ri", "ro", "is ", "co", "f t", "are", "ea", ". ", "her", " m", "er ", " p",
+      "es ", "by", "they", "di", "ra", "ic", "not", "s, ", "d t", "at ", "ce", "la",
+      "h ", "ne", "as ", "tio", "on ", "n t", "io", "we", " a ", "om", ", a", "s o",
+      "ur", "li", "ll", "ch", "had", "this", "e t", "g ", "e\r\n", " wh", "ere",
+      " co", "e o", "a ", "us", " d", "ss", "\n\r\n", "\r\n\r", "=\"", " be", " e",
+      "s a", "ma", "one", "t t", "or ", "but", "el", "so", "l ", "e s", "s,", "no",
+      "ter", " wa", "iv", "ho", "e a", " r", "hat", "s t", "ns", "ch ", "wh", "tr",
+      "ut", "/", "have", "ly ", "ta", " ha", " on", "tha", "-", " l", "ati", "en ",
+      "pe", " re", "there", "ass", "si", " fo", "wa", "ec", "our", "who", "its", "z",
+      "fo", "rs", ">", "ot", "un", "<", "im", "th ", "nc", "ate", "><", "ver", "ad",
+      " we", "ly", "ee", " n", "id", " cl", "ac", "il", "</", "rt", " wi", "div",
+      "e, ", " it", "whi", " ma", "ge", "x", "e c", "men", ".com"
+    ],
+    self::CODEBOOK_EMAIL   => [ // WARNING: only add to the end, or existing compressions will be messed up
+      // single chars
+      'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
+      '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '_', '+', '.', '@',
+      // common domains
+      '@gmail', '@hotmail', '@yahoo', '@comcast', '@aol', '@msn', '@live', '@verizon', '@me', '@shaw', '@outlook', '@gmx',
+      // common TLDs
+      '.com', '.net', '.edu', '.org', '.ca', '.de', '.fr', '.org', '.au', '.ru',
+      // top 100 two-letter combos (local part only)
+      'an','er','ar','on','in','ma','le','en','el','ri','ch','re','ll','ha','ra','al','st','li','ne','te','la','at','is','he','ro','am',
+      'es','or','th','ke','ic','nd','il','ie','be','da','de','na','mi','as','so','ng','co','ck','n.','sh','ca','se','nn','tt','ol','ni',
+      'sa','ti','me','ac','to','ey','et','ea','ho','br','ns','ia','rt','ee','it','jo','lo','ta','e.','ka','ad','ja','ur','ba','im','nt',
+      'ge','au','sc','mo','os','ss','vi','hi','ul','rd','em','rs','pa','ki','ve','us','wa','do','ga','ry','a.','rr',
+      // top 50 three-letter combos (local part only)
+      'and','son','ell','man','ill','cha','ste','mar','ris','ter','han','ann','ing','lle','the','lin','ich','che','lan','har','ber','all',
+      'her','ton','ick','dan','lli','mat','ale','att','ard','an.','ric','ers','art','ran','ley','ani','ren','ine','ath','tin','sha','der',
+      'car','nne','nic','ian','nie','dav','bit',
+      // common four-letter combos (local part only)
+      'chri','andr','john','matt','davi','drew','icha','stin','mich','nder','illi','elle','will','rian','bert',
+      'ryan','anie','rick','alex','ster','nson','ande','coin',
+    ]
+  ];
+
+  protected static function getEncodeBook($codebook)
+  {
+    if (!isset(static::$encodeBooks[$codebook]))
+    {
+      static::$encodeBooks[$codebook] = array_flip(static::getDecodeBook($codebook));
+    }
+    return static::$encodeBooks[$codebook];
+  }
+
+  protected static function getDecodeBook($codebook)
+  {
+    if (!static::$decodeBooks[$codebook])
+    {
+      throw new Exception('decodebook ' . $codebook . ' does not exist');
+    }
+    if (count(static::$decodeBooks[$codebook]) > static::VERBATIM_CHAR)
+    {
+      throw new Exception('decodebook ' . $codebook . ' must be at most ' . static::VERBATIM_CHAR . 'entries');
+    }
+    return static::$decodeBooks[$codebook];
+  }
+
+
+  /**
+   * @param string $str
+   * @param string $codebook
+   *
+   * @return string
+   */
+  public static function encode($str, $codebook = self::CODEBOOK_DEFAULT)
+  {
+    $encodeBook = static::getEncodeBook($codebook);
+
+    $inLen      = strlen($str);
+    $inIdx      = 0;
+    $output     = '';
+    $verbatim   = '';
+    $maxItemLen = max(array_map('strlen', array_keys($encodeBook)));
+
+    while ($inIdx < $inLen)
+    {
+      $encode = false;
+
+      for ($j = min($maxItemLen, $inLen - $inIdx); $j > 0; $j--)
+      {
+        $code = isset($encodeBook[substr($str, $inIdx, $j)]) ? $encodeBook[substr($str, $inIdx, $j)] : null;
+        if ($code !== null)
+        {
+//          echo substr($str, $inIdx, $j) . " = $code\n";
+          if (strlen($verbatim))
+          {
+            $output .= static::flushVerbatim($verbatim);
+            $verbatim = '';
+          }
+          $output .= chr($code);
+          $inIdx += $j;
+          $encode = true;
+          break;
+        }
+      }
+
+      if (!$encode)
+      {
+//        echo "VERBATIM\n";
+        $verbatim .= $str[$inIdx];
+        $inIdx++;
+        if (strlen($verbatim) == 255) // any longer, and we can't represent the length as a single char
+        {
+          $output .= static::flushVerbatim($verbatim);
+          $verbatim = '';
+        }
+      }
+    }
+
+    if (strlen($verbatim))
+    {
+      $output .= static::flushVerbatim($verbatim);
+    }
+    return $output;
+  }
+
+  /**
+   * @param string $str
+   * @param string $codebook
+   *
+   * @return string
+   */
+  public static function decode($str, $codebook = self::CODEBOOK_DEFAULT)
+  {
+    $decodeBook = static::getDecodeBook($codebook);
+
+    $output = '';
+    $i      = 0;
+
+    while ($i < strlen($str))
+    {
+      $code = ord($str[$i]);
+      if ($code == static::VERBATIM_CHAR)
+      {
+        $output .= $str[$i + 1];
+        $i += 2;
+      }
+      elseif ($code == static::VERBATIM_STR)
+      {
+        $len = ord($str[$i + 1]);
+        $output .= substr($str, $i + 2, $len);
+        $i += 2 + $len;
+      }
+      elseif (!isset($decodeBook[$code]))
+      {
+        return null; // decode error. throw exception?
+      }
+      else
+      {
+        $output .= $decodeBook[$code];
+        $i++;
+      }
+    }
+    return $output;
+  }
+
+  protected static function flushVerbatim($verbatim)
+  {
+    $output = '';
+    if (!strlen($verbatim))
+    {
+      return $output;
+    }
+
+    if (strlen($verbatim) > 1)
+    {
+      $output .= chr(static::VERBATIM_STR);
+      $output .= chr(strlen($verbatim));
+    }
+    else
+    {
+      $output .= chr(static::VERBATIM_CHAR);
+    }
+    $output .= $verbatim;
+    return $output;
+  }
+}
\ No newline at end of file