A technique for conducting secure financial and informational transactions via portable smart devices is disclosed, in which two transaction devices, e.g. an ATM and a smartphone or other smart connected device are both substantially simultaneously accessible by the user and are both independently connected with the account server by a secure connection between the transaction device for the ATM and a secure connection between the smartphone and a cellphone tower. Thus, authentication is provided by secure login on the two devices, i.e. the transaction device and the cellphone. Once the devices are both connected to the account server, handshaking between the two devices to confirm pairing of the right two devices is prompted, at which point, a transaction may proceed.