STK as it appears on the phone menu and left after its opened SIM Application Toolkit (commonly referred to as STK ) is a standard of the Global System for Mobile ( GSM) system which enables the Subscriber Identity Module (SIM) to initiate actions which can be used for various value-added services. Most of the mobile banking solutions use STK (SIM application toolkit) to create secure, verifiable channels for transactions. Although STK is claimed to be more secure, it has the limitation that changes and upgrades require either that the SIM be exchanged or that the SIM, phone and network is set up to use secure SMS SIM updating in other words The STK technology has limited independent development support available. Maybe that explains why we have had an exodus of networks moving to the USSD codes. USSD (Unstructured Supplementary Service Data) is a Global System for Mobile (GSM) communication technology that is used to send text between a mobile phone and
