A system and method for sharing files securely includes server software on a first device configured to communicate with server software operating on one or more other preauthorized devices, such as a second device. The servers communicate with each other securely using cryptographic information exchanged during a preauthorization phase using a range-limited communication channel. The server on the first device obtains file information from the other preauthorized device(s) and combines the information with local file information from the first device. This combined file information is sent to client software operating on the machine, which presents the combined file information to users.