Method of Encrypted Communication with Restricted Rate of Stored Encryption Key Retrievals

a technology of encrypted communication and encryption key, applied in the field of secure communication, can solve the problems of home refill operation or clone manufacture in countries with weak industrial property protection, consumer to blame system manufacturer and not admit the use of non-authorized consumables, and slightly complicate matters, so as to frustrate the attacker and reduce nois

Inactive Publication Date: 2011-03-31
ZAMTEC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0024]Preferably, the generation of each of the variant keys using the one-way function is a calculation that has several separate terms, and the device is configured to use random arrangements of the terms. This frustrates the attacker by making it harder to combine multiple power consumption waveforms to reduce noise.

Problems solved by technology

However this does not stop home refill operations or clone manufacture in countries with weak industrial property protection.
For example, poorly filtered ink may clog print nozzles in an ink jet printer, causing the consumer to blame the system manufacturer and not admit the use of non-authorized consumables.
This slightly complicates matters in that refilling must be possible, but not via unauthorized home refill or clone refill means.
Typically, correct bits within the signature cause many logic states to change and so the power spikes.

Method used

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  • Method of Encrypted Communication with Restricted Rate of Stored Encryption Key Retrievals
  • Method of Encrypted Communication with Restricted Rate of Stored Encryption Key Retrievals
  • Method of Encrypted Communication with Restricted Rate of Stored Encryption Key Retrievals

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Embodiment Construction

[0106]Particular embodiments of the invention will now be described with reference to the Applicant's Memjet™ printing system. However, the skilled worker will understand that the invention is not restricted to use in a printing system and may be employed in a wide range of applications requiring encrypted communication and authentication of related entities.

Side Channel Behaviour of Prior Art QA Chip

[0107]The invention builds on the key management mechanisms presented in U.S. Pat. No. 7,557,941 cross referenced above and therefore adheres to the same terminology. Each ink cartridge in a Memjet™ Printer contains a QA (Quality Assurance) Chip that stores and uses a valuable base key to authenticate itself to software running in the Print Engine Controller (SOPEC) chip. Compromise of this key would allow an attacker to build clone ink cartridges that are accepted by any printer of the appropriate model.

[0108]The prior art or unimproved QA Chip will, in response to an attacker's comman...

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PUM

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Abstract

A method of encrypted communication between entities in a manner that frustrates side channel attacks attempting to determine an encryption key. The method involves providing a device with an encryption key stored in memory, providing an external entity with identity data for transmission to the device, applying a one way function to the encryption key and the identity data to generate a variant key, authenticating communications between the device and the external entity with the variant key and limiting the number of times the encryption key is retrieved from the first memory in a given period of time.

Description

FIELD OF THE INVENTION[0001]The present invention relates to the field of secure communication. The invention has been developed primarily to enable communication between various integrated circuits in a printer, including cartridges for use with the printer, and will be described with reference to this application. However, it will be appreciated that the invention has broad application in the general field, including use in software, hardware and combinations of the two.CO-PENDING APPLICATIONS[0002]Various methods, systems and apparatus relating to the present invention are disclosed in the following co-pending applications filed by the applicant or assignee of the present invention simultaneously with the present application:PLT095USPLT096USPLT097USPLT098USPLT099US[0003]The disclosures of these co-pending applications are incorporated herein by cross-reference.RELATED SYSTEMS, METHODS AND DEVICES[0004]Various methods, systems and apparatus relating to the present invention are di...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): H04L9/00
CPCH04L9/003H04L9/3247H04L9/0897G06F21/62H04L9/16H04L9/32
Inventor STARR, MATTHEW RAYMONDPRICE-WHITE, STEPHEN CAMERON
Owner ZAMTEC
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