# US 8,542,828 B2 · Cryptographic secret key distribution

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 8,542,828 B2
- Document ID: US8542828B2
- Status: Granted
- Kind: B2
- Application number: 13/058,556
- Filed: 2009-08-06
- Published: 2011-06-09
- Granted: 2013-09-24
- Earliest claimed: 2008-08-14
- Assignees: Koninklijke Philips N.V.
- Applicants: Philip Andrew Rudland; Bas Driesen; Philip Anthony Jamieson
- Inventors: Philip Andrew Rudland; Bas Driesen; Philip Anthony Jamieson
- Web page: https://patentgrep.com/patent/US8542828B2

## CPC

- H04L 9/0841: {involving Diffie-Hellman or related key agreement protocols}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

The present invention relates to cryptographic secret key distribution, wherein a value for a number of iterations can be individually set, so that the number of messages to be exchanged during generating a cryptographic secret key can be varied based on the set value of the iteration number.

## Claims

### Claim 1

An apparatus for transmitting or receiving data securely using a cryptographic secret key, said apparatus comprising:
a setting unit which provides a setting function for setting an iteration number, wherein a value for a number of iterations corresponding to the iteration number can be individually set; and
a key generation controller for controlling a number of messages to be exchanged during generating said cryptographic secret key, wherein the number of messages to be exchanged can be varied based on a set value of said iteration number, and wherein the messages comprise test RSSI (T_rssi) messages, marginal readings (MR) messages, key material (KM) messages or key transport (KT) messages.

### Claim 2 (depends on 1)

The apparatus according to claim 1, wherein said setting unit is arranged to generate or provide said iteration number in response to an initiation of a key establishment.

### Claim 3 (depends on 1)

The apparatus according to claim 1, wherein said setting unit is arranged to generate said iteration number based on an input operation at said apparatus.

### Claim 4 (depends on 1)

The apparatus according to claim 1, wherein said setting unit is arranged to generate said iteration number based on a type of said data.

### Claim 5 (depends on 1)

The apparatus according to claim 1, wherein said setting unit is arranged to receive said iteration number from another transmission side.

### Claim 6 (depends on 1)

The apparatus according to claim 1, wherein said apparatus comprises a transmitter arranged to transmit said iteration number to another transmission side.

### Claim 7 (depends on 1)

The apparatus according to claim 1, further comprising a memory for storing a value of said iteration number.

### Claim 8 (depends on 1)

The apparatus according to claim 1, further comprising a counter for counting said number of messages to be exchanged during said generating said cryptographic secret key.

### Claim 9 (depends on 1)

The apparatus according to claim 1, wherein said apparatus is arranged to generate said cryptographic secret key based on a combination of randomly generated numbers obtained from said number of messages to be exchanged.

### Claim 10 (depends on 9)

The apparatus according to claim 9, wherein said combination is an exclusive-or combination.

### Claim 11

A method for transmitting or receiving encrypted data using a cryptographic secret key, said method comprising:
providing, via a setting unit, a setting function for setting an iteration number, wherein a value for a number of iterations corresponding to the iteration number can be individually set; and
controlling, via a key generation controller, a number of messages to be exchanged during generating said cryptographic secret key, wherein the number of messages to be exchanged can be varied based on a set value of said iteration number, and wherein the messages comprise test RSSI (T_rssi) messages, marginal readings (MR) messages, key material (KM) messages or key transport (KT) messages.

### Claim 12 (depends on 1)

A system for distributing a cryptographic secret key, said system comprising at least one first device having an apparatus according to claim 1 for transmitting said iteration number, and at least one second device for receiving said transmitted iteration number and for generating said cryptographic secret key based on said received iteration number.

### Claim 13 (depends on 11)

A non-transitory computer-readable medium embodied with a computer program comprising code executable by a computer device for producing the steps of the method of claim 11 when run on the computer device.