While it's alive to the challenges of providing a secure mobile banking platform, Commonwealth Bank is playing its cards close to its chest about exactly how it is achieving that goal.Adam Bennett, chief information officer of the retail bank, will only say that a number of security measures have been taken, including strong authentication and proactive monitoring of the Kaching platform.Speaking at yesterday's Kaching launch, Bennett said: "Information is all stored in the data centres" not the smartphone itself and "to access you need to log in using Netbank or a PIN".In addition, access to the service will be locked to specific devices. "If you lose the phone you can call the bank and we can immediately disable any future transactions," he said.The bank also intends to identify and track patterns of activity and the use of the app for Facebook payments, which will be important to identify and stop any money-laundering attempts. For payments made to Facebook friends, the recipient will have to be sent a special code separately, via SMS or email, for example, which they will then input, along with their bank account details, to complete the transaction and have the funds transferred.For users who opt to buy a near-field communication enabled case to use alongside Kaching, the bank is extending its 100 per cent PayPass guarantee, so "if someone else uses it fraudulently we will reimburse the customer", says Bennett, as long as steps have been taken to swiftly alert the bank. The app has also been tuned so the NFC capability switches itself off after 60 seconds. Down the track, the bank is considering harnessing other smartphone functions, such as the camera. It has already raised the possibility of using a photo captured on a smartphone for biometric authentication.