In response to at least one message received by a processor of a gateway server from a user device wherein each message requests that an encryption key be downloaded to the user device, the processor generates at least one unique encryption key for each message and sends the at least one generated encryption key to the user device, but does not store any of the generated encryption keys in the cloud. For each encryption key having been sent to the user device, the processor receives each encryption key returned from the user device. For each encryption key received from the user device, the processor stores each received encryption key in the cloud.