A method and apparatus for establishing a trust relationship between users is disclosed. The apparatus includes at least two user devices containing the Application, a service provider server (SPS) comprising an application programming interface (API), a network communicably coupling the sender device, the receiver device and the SPS, and an out-of-band (OOB) channel, separate from the network, communicably coupling the sender device and the receiver device. The method includes obtaining a receiver's Public Key provided by an Application Programming Interface (API) on an service provider server, encrypting a verification message with the Receiver's Public key and the Sender's Private Key, sending the encrypted verification message from the Sender's device to the Receiver's device through the out-of-band channel, decrypting the encrypted verification message using Receiver's Private Key and Sender's Public Key, and communicating decrypted verification message via out-of-band channel.