Patent ID: 8250363

Claim:
A method of provisioning a plurality of devices with respective new one-time pad data for use in interacting with an apparatus holding the same one-time pad data, the method comprising: provisioning a first device with new one-time pad data including a block of secret random data that is, or will become, available to said apparatus, wherein the block of secret random data is logically divided into pages of predetermined size; distributing the secret random data received by the first device between said devices in a hierarchical distribution pattern headed by the first device; each device, other than those at an end of the distribution hierarchy, retaining a part of the secret random data it receives and passing on respective parts of the remaining data to each device dependent from it in the distribution hierarchy, the parts of the secret random data that are retained or passed on being whole pages, using that part of the secret random data retained by each device to provide the device with its said new one-time pad data, wherein at least one said device has pre-existing one-time pad data, the device using the secret random data it has retained to provide said new one-time pad data by combining the retained secret random data with the pre-existing one-time pad data.