CommonwealthBank, in Australia, Barclays, in the United Kingdom, Chase and Citibank, in the United States and now Ita, in Brazil are the only banks in the world that have a mobile application in which transfers can be made as whoever sends a message on whatsapp.
The application just launched by Ita, one of the largest Brazilian banks, is compatible with both android and iphone. His name is Tokpag, an application that is associated with a telephone number and checking account so that, after informing the corresponding password, you can send money to any other user of the same bank who also has the application installed.
You just have to select the desired user, indicate the amount and press send, without further bureaucracy, following the philosophy of the thousands of instant messaging applications that are invading the official markets of the companies.
According to those responsible for the system in g1, the security is similar to that used in your Internet Bank. The password used is the same, and the care to be performed is similar. The only thing they have done is isolate the most used functionality of their system (the transfer) and offer an application that helps users to pay and collect in a simple and practical way.
You can take a look at its Android (here) and iOS (here) versions.