Document Authentication Using Diffie-Hellman Protocol

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Solution Overview

Problem

Existing Password Authenticated Key Exchange (PAKE) protocols, such as PACE, are not optimized for high execution speed, limiting their suitability for time-critical applications like contactless chip card transactions, and alternative algorithms like MIFARE or Legic offer lower security for many applications.

Innovation Solution

A method using the Diffie-Hellman protocol with a static and ephemeral key exchange to authenticate a document to a reading device, where a first set of parameters is stored in the reading device and dynamically derived parameters are used for secure key agreement, reducing the number of request-response cycles and enhancing security.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PACE protocol is used for authentication, then security level is improved, but execution speed deteriorates

Engineering Contradiction:
Improvesecurity levelVSAvoidexecution speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent pre-calculates and stores the first Diffie-Hellman key pair and first authentication value in the card during initialization. This preliminary action eliminates the need to perform these computationally intensive operations during the actual authentication process, thereby maintaining high security while significantly reducing execution time during contactless transactions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The authentication process is divided into two distinct phases: a preparation phase where computationally intensive operations are performed and stored, and an execution phase where only lightweight verification operations are needed. This segmentation allows the system to maintain high security requirements while achieving the speed necessary for contactless applications.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If contactless chip card authentication is performed, then convenience is improved, but authentication speed deteriorates

Engineering Contradiction:
ImproveconvenienceVSAvoidauthentication time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The card performs and stores the results of computationally intensive authentication operations in advance. During contactless authentication, only lightweight verification operations are required, making the process fast and convenient for users while maintaining high security standards.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates and stores copies of authentication data (first key pair and first authentication value) in the card's memory during initialization. These pre-computed copies enable rapid authentication during contactless transactions without requiring repeated computation of the same cryptographic values.

Inventive Principle:
Principle #26Copying

3Reliability

If multiple authentication query steps are performed, then security is improved, but processing time increases

Engineering Contradiction:
Improveauthentication securityVSAvoidprocessing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The card pre-computes and stores the first authentication value during initialization. This eliminates the need for the terminal to query the card for this value and perform time-consuming computations during the authentication process, reducing the number of interactive query steps while maintaining security through the use of pre-validated authentication data.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2880810B1Authentication of a document to a reading device
Publication Date: 2018.05.16 BUNDESDRUCKEREI GMBH
  • EP2880810B1 patent drawingFigure 1
  • EP2880810B1 patent drawingFigure 2a
  • EP2880810B1 patent drawingFigure 2b

AI summary

The invention relates to a method for authenticating a document (ICC, 501) to a reader (IFD, 550) using a Diffie-Hellman protocol, comprising: - production (102, 234, 334, 334', 434, 434') of a first data value (RND.ICC) by the document; - calculation (104, 236, 336, 336', 436, 436') of a ciphertext (E(s)) that contains at least the first data value (RND.ICC) by the document using a secret key (SK); - transmission (106) of the ciphertext (E(s)) from the document to the reader; - decryption (108, 238, 338, 338', 438, 438') of the ciphertext E(s) by the reader using the secret key (SK); - first performance (110) of the Diffie-Hellman protocol to agree a first shared secret (H); - second performance (112) of the Diffie-Hellman protocol to agree a second shared secret (H); - authentication (122) of the document to the reader using the second secret (H').