Validation protocol and system

• US 7,249,108 B1
• Filed: 03/02/2000
• Issued: 07/24/2007
• Est. Priority Date: 07/15/1997
• Status: Expired due to Fees

• Current Assignee: Memjet Technology Ltd. (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Lapstun, Paul, Walmsley, Simon Robert
• Primary Examiner(s): NGUYEN, NGA B
• Application Number:
  US09/517,539
• Time in Patent Office: 2,700 Days
• Field of Search: 705/16, 705/17, 705/18, 705/41, 705/64, 705/65, 705/71, 705/67, 380/24, 380/25, 380/30, 380/46, 380/23, 380/9, 380/51, 380/259, 380/277, 235/379, 235/380, 713/155, 713/159, 713/167, 713/168, 713/170, 713/176, 713/182, 713/189
• US Class Current: 705/64
• CPC Class Codes: B41J 2/165 Preventing or detecting of nozzle clogging, e.g. cleaning, capping or moistening for nozzles
• CPC Class Codes: B41J 2/175 Ink supply systems ; Circuit parts therefor
• CPC Class Codes: B41J 2/17546 electronically
• CPC Class Codes: B41J 2/17596 Ink pumps, ink valves
• CPC Class Codes: B41J 3/42 Two or more complete typewriters coupled for simultaneous operation
• CPC Class Codes: B41J 3/44 Typewriters or selective printing mechanisms having dual functions or combined with, or coupled to, apparatus performing other functions
• CPC Class Codes: G06Q 30/01 Customer relationship services
• CPC Class Codes: G06Q 30/0185 Product, service or business identity fraud
• CPC Class Codes: G09C 1/00 Apparatus or methods whereby a given sequence of signs, e.g. an intelligible text, is transformed into an unintelligible sequence of signs by transposing the signs or groups of signs or by replacing them by others according to a predetermined system cryptographic typewriters G09C3/00
• CPC Class Codes: H04L 2209/043 of tables, e.g. lookup, substitution or mapping
• CPC Class Codes: H04L 2209/26 Testing cryptographic entity, e.g. testing integrity of encryption key or encryption algorithm
• CPC Class Codes: H04L 9/003 for power analysis, e.g. differential power analysis [DPA] or simple power analysis [SPA]
• CPC Class Codes: H04L 9/0662 with particular pseudorandom sequence generator
• CPC Class Codes: H04L 9/3242 involving keyed hash functions, e.g. message authentication codes [MACs], CBC-MAC or HMAC
• CPC Class Codes: H04L 9/3271 using challenge-response
• CPC Class Codes: H04L 9/50 using hash chains, e.g. blockchains or hash trees
• CPC Class Codes: H04N 1/21 Intermediate information storage H04N1/387, H04N1/41 take precedence ; for control between transmitter and receiver or between image input and image output device H04N1/32358; indexing, editing G11B27/00
• CPC Class Codes: H04N 1/2112 using still video cameras
• CPC Class Codes: H04N 1/2154 the still video camera incorporating a hardcopy reproducing device, e.g. a printer
• CPC Class Codes: H04N 2101/00 Still video cameras
• CPC Class Codes: H04N 23/00 : Cameras or camera modules comprising electronic image sensors; Control thereof
• CPC Class Codes: H04N 5/2628 : Alteration of picture size, shape, position or orientation, e.g. zooming, rotation, rolling, perspective, translation

Abstract

This invention concerns a validation protocol for determining whether an untrusted authentication chip is valid, or not. The protocol may be used to determine the physical presence of a valid authentication chip and from that determine whether a consumable containing the chip is valid. In another aspect the invention also concerns a system for validating the chip. The invention involves generating a random number in a trusted authentication chip, then applying a keyed one way function to the random number in both the trusted authentication chip and an untrusted authentication chip and comparing the outcomes. A match indicates that the untrusted chip is valid.

Claims

1. A validation protocol performed in a system for determining whether an untrusted authentication chip in communication with the system is valid, or not, including the steps of:

generating a random number in a trusted authentication chip in communication with the system;

applying, in the trusted authentication chip, a keyed one way function to the random number using a first secret key from the trusted authentication chip to produce a first encrypted outcome;

applying, in the untrusted authentication chip, a keyed one way function to the random number using a second secret key from the untrusted authentication chip to produce a second encrypted outcome;

comparing, using the system, the first encrypted outcome and the second encrypted outcome, without knowledge of the first and second secret keys, and in the event of a match considering the untrusted chip to be valid;

otherwise considering the untrusted chip to be invalid.

2. A validation protocol according to claim 1, where the domain of the random numbers generated is non-deterministic.

3. A validation protocol according to claim 1, where the keyed one-way function is a symmetric cryptograph, a random number sequence, or a message authentication code.

4. A validation protocol according to claim 1, where the first and second keys have a minimum size of 128 bits where the one-way function is a symmetric cryptographic function.

5. A validation system for determining whether an untrusted authentication is valid, or not, where the system comprises:

a random number generator to generate a random number;

a trusted authentication chip, the trusted authentication chip including a keyed one-way function and a first secret key for the one-way function, the trusted authentication chip applying the keyed one way function to the random number using the first secret key to produce a first encrypted outcome;

an untrusted authentication chip, the untrusted authentication chip including the keyed one way function and a second secret key, the untrusted authentication chip applying the keyed one way function to the random number using the second secret key to produce a second encrypted outcome; and

comparison means to compare the first encrypted outcome and the second encrypted outcome, without knowledge of the first and second secret keys;

whereby, in the event of a match between the outcomes from the trusted chip and the untrusted chip, the untrusted chip is considered to be valid.

6. A validation system according to claim 5, where the trusted authentication chip contains a random function to produce random numbers from a seed, and the function advances after every random number is produced so that the next random number will be produced from a new seed.

7. A validation system according to claim 5, where each trusted authentication chip contains a random function to produce random numbers from a seed, and for a group of authentication chips, each chip has a different initial seed, so that the first call to each chip requesting a random number will produce different results for each chip in the group.

8. A validation system according to claim 6, where the domain of the random numbers generated is non-deterministic.

9. A validation system according to claim 5, where the keyed one-way functions is a symmetric cryptograph, a random number sequence, or a message authentication code.

10. A validation system according to claim 5, where the first or second keys for the keyed one-way function have at least 128 bits where the one-way function is a symmetric cryptographic function.