dragffy.com

I was getting the above error from CodeIgniter after urlencoding some base64 encoded binary data and passing it as a URI parameter to CodeIgniter. I looked in the config.php file and found that percent signs were allowed here:
$config['permitted_uri_chars'] = 'a-z 0-9~%.:_\-';

After some hunting around I found that CodeIgniter is not accepting this in the URI because the actual characters (that are encoded) fall outside the ASCII range. CodeIgniter is actually decoding the characters before testing them. The fix was quite simple, open up libraries/URI.php and go to line 189 where it says:
if ( ! preg_match("|^[".preg_quote($this->config->item('permitted_uri_chars'))."]+$|i", $str))
and change it to:

if ( ! preg_match("|^[".preg_quote($this->config->item('permitted_uri_chars'))."]+$|i", rawurlencode($str)))

Basically wrapping $str in the urlencode() function.