XXTEA, an alternative replacement of KASUMI cipher algorithm in A5/3 GSM and f8, f9 UMTS data security functions

Mobile communication networks are nowadays rather known as Wi-Fi for internet networks and less the classical radio voice communications networks. The most used mobile networks remains however the well known and a little bit old from now GSM/2G (Global System for Mobile Communication/2
^nd
Generation) and the ,,former” new entry, but full used UMTS/3G (Universal Mobile Telecommunication System/3
^rd
Generation). Of course, the trend is now going to make changes for 4G and 5G mobile networks. Opposite to this extraordinary progress of the mobile communication networks, is now rising a hidden danger against the users, especially when they use to access the bank accounts via mobile terminals. The probability to eavesdropping conversations is only the top of the iceberg. More important is how to protect the data exchange information against third party interceptors when a banking operation is done via mobile communication terminal. Thus, it seems that even nowadays, we can deal with the weaknesses of some embedded security algorithms still in use: A5/3 for GSM (2G) networks and f8 and f9 for UMTS (3G) networks. The paper shows an alternative for these algorithms, in order to improve the crypto protection of the data (and voice) in such mobile networks.