Patent ID: 9246672
Filing Date: 2016-01-26
CPC Classification: H04L

Claim Text:
1. A method for facilitating secure communication between a first device and a second device, the method comprising, at a third device: receiving, from the first device, an encrypted first message and a first index, said encrypted first message specifying the second device as a destination; selecting a master key; forming a decrypted first message by using a first message key to decrypt the encrypted first message, wherein the first message key comprises a sequence of bits of a key length selected from the master key starting at a first location in the master key referenced by the first index and moving in a first direction; determining a previously recorded second index to a second location in the master key; forming a re-encrypted first message by using a second message key to encrypt the decrypted first message, the second message key comprising a sequence of bits of the key length selected from the master key moving in a direction opposite to the first direction and stopping at the second location in the master key referenced by the second index; and transmitting, to the second device, the re-encrypted first message and the second index; wherein no portion of the master key is used more than once.