US Patent 11483140 Secure out-of-band symmetric encryption key delivery

Trusted nodes in a network perform secure out-of-band symmetric encryption key delivery to user devices. A first trusted node receives a request from a first user device to deliver symmetric encryption keys to the first user device and a second user device, as a pair of user devices. The first trusted node delivers a second symmetric encryption key to the second user device, via trusted nodes. The first trusted node receives confirmation of delivery of the second symmetric encryption key. Responsive to the confirmation of delivery, the first trusted node delivers the first symmetric encryption key to the first user device.