A cash register cloud server (150) for supporting an electronic payment based on an interaction between a mobile merchant communication device (120) and a customer payment device (110) is disclosed. The cash register cloud server (150) comprises a processing circuitry (151) configured to implement a plurality of cash register applications (151a). Moreover, the cash register cloud server (150) comprises a communication interface (153) configured to receive electronic payment data based on an user input from the mobile merchant communication device (120) via a secure channel. The processing circuitry (151) is further configured to assign the electronic payment data to one of the plurality of cash register applications (151a) and to generate an authentication request for requesting further processing of the electronic payment, wherein the authentication request comprises authentication information based on a cryptographic key of the one of the plurality of cash register applications (151a). The communication interface (153) is further configured to transmit the authentication request to the mobile merchant communication device (120) and/or a payment cloud server (140) via a further secure channel.