Even if a mobile device is not equipped with a QR-code reader, there are some add-on tools that decode QR codes simply by positioning the device in front of the code. The decoding is carried out automatically within the streaming flw; the user does not have to take a picture of the QR code. Examples are QuickMark and i-nigma readers, two free tools that use this technique and are available for many manufactured models and devices. QuickMark also provides extension functionalities to QR codes by allowing partial or entire encryption of codes (Sakamura and
Koshizuka, 2005)