A system and method for enabling secure device-to-device (D2D) communication between a plurality of user devices. The method includes providing public and private keys for each of the user devices, the private key arranged to decrypt data encrypted by the corresponding public key. A sender user device creates a digital signature using its private key. The sender double-encrypts a transmission using both the public keys of a recipient user device and a first relay user device. The transmission is transmitted from the sender to the recipient through a plurality of relay user devices. Each relay user device receives the transmission, decrypts a first layer of encryption with its private key, encrypts the transmission with the public key of a subsequent user device; and forwards the data transmission to the subsequent user device. The recipient authenticates the digital signature of the sender using the public key of the sender.