diff --git a/class.smtp.php b/class.smtp.php
index e5d86bc1..ddb624a6 100644
--- a/class.smtp.php
+++ b/class.smtp.php
@@ -414,10 +414,81 @@ class SMTP {
             return false;
         }
         break;
+      case 'CRAM-MD5':
+        // Start authentication
+        fputs($this->smtp_conn,"AUTH CRAM-MD5" . $this->CRLF);
+
+        $rply = $this->get_lines();
+        $code = substr($rply,0,3);
+
+        if($code != 334) {
+          $this->error =
+            array("error" => "AUTH not accepted from server",
+                  "smtp_code" => $code,
+                  "smtp_msg" => substr($rply,4));
+          if($this->do_debug >= 1) {
+            $this->edebug("SMTP -> ERROR: " . $this->error["error"] . ": " . $rply . $this->CRLF . '<br />');
+          }
+          return false;
+        }
+
+		// Get the challenge
+		$challenge = base64_decode(substr($rply,4));
+
+		// Build the response
+		$response = $username . ' ' . $this->hmac($challenge, $password);
+
+        // Send encoded credentials
+        fputs($this->smtp_conn, base64_encode($response) . $this->CRLF);
+
+        $rply = $this->get_lines();
+        $code = substr($rply,0,3);
+
+        if($code != 334) {
+          $this->error =
+            array("error" => "Credentials not accepted from server",
+                  "smtp_code" => $code,
+                  "smtp_msg" => substr($rply,4));
+          if($this->do_debug >= 1) {
+            $this->edebug("SMTP -> ERROR: " . $this->error["error"] . ": " . $rply . $this->CRLF . '<br />');
+          }
+          return false;
+        }
+        break;
     }
     return true;
   }
 
+  /**
+   * Works like hash_hmac('md5', $data, $key) in case that function is not available
+   * @access private
+   * @return string
+   */
+  private function hmac($data, $key) {
+	  if (function_exists('hash_hmac')) {
+		  return hash_hmac('md5', $data, $key);
+	  }
+
+	  // The following borrowed from http://php.net/manual/en/function.mhash.php#27225
+
+	  // RFC 2104 HMAC implementation for php.
+	  // Creates an md5 HMAC.
+	  // Eliminates the need to install mhash to compute a HMAC
+	  // Hacked by Lance Rushing
+
+	  $b = 64; // byte length for md5
+	  if (strlen($key) > $b) {
+  		$key = pack("H*",md5($key));
+	  }
+	  $key  = str_pad($key, $b, chr(0x00));
+	  $ipad = str_pad('', $b, chr(0x36));
+	  $opad = str_pad('', $b, chr(0x5c));
+	  $k_ipad = $key ^ $ipad ;
+	  $k_opad = $key ^ $opad;
+
+	  return md5($k_opad  . pack("H*",md5($k_ipad . $data)));
+  }
+
   /**
    * Returns true if connected to a server otherwise false
    * @access public