Method for authenticating payment data, corresponding devices and programs

Patent metadata

Field	Value
Publication number	US-10922679-B2
Application number	US-201716314174-A
Country	US
Kind code	B2
Filing date	Jun 30, 2017
Priority date	Jun 30, 2016
Publication date	Feb 16, 2021
Grant date	Feb 16, 2021

Abstract

A method for authenticating data, implemented during a payment transaction between a merchant's communications terminal and a user device of the type including authentication by the communications terminal of at least one message generated by the user device, by using near field communications wireless data. The method includes the following acts by the user's device: obtaining an authentication code from the message, a piece of random data and a hash function; obtaining a first signature component from the message, the random piece of data, a public key of the communications terminal, a first private key of the user device and the authentication code; obtaining a second signature component from the message, the random piece of data, the public key of the communications terminal, a second private key of the user device and the authentication code; and transmitting the authentication code and of the two signature components to the communications terminal.

First claim

The invention claimed is:

1. A method of authenticating at least one piece of data, implemented during a payment transaction taking place between a communications terminal and a user device of the type comprising authentication by the communications terminal of at least one message m generated by the user device, by using a near field communications wireless data link, the method comprising the following acts performed by the user device:
calculating an authentication code S 1 from the message m, a piece of random data t and a hash function H;
calculating a first signature component S 2 from the message m, the random piece of data t, a public key Z of the communications terminal, a first private key x of the user device and from the authentication code S 1 ;
calculating a second signature component S 3 from the message m, the random piece of data t, the public key of Z of the communications terminal, a second private key y of the user device and from the authentication code S 1 ; and
transmitting, to the communications terminal, the authentication code S 1 and the two signature components S 2 and S 3 .

2. The method of authentication according to claim 1 , comprising the following acts performed by the communications terminal:
obtaining a first reference value denoted as U [r1] from the first signature component S 2 , a public key X of the user device, a private key z of the communications terminal and the authentication code S 1 ;
obtaining a second reference value denoted as U [r2] from the second signature component S 3 , a public key Y of the user device, the private key z, and the authentication code S 1 ; and
verifying that the first reference value U [r1] is equal to the second reference value U [r2] ;
and, when the two values are equal:
verifying that the value H(U [r2] ) and/or H(U [r1] ) is equal to S 1 ; and
issuing an assertion of authentication when the preceding verification step is positive.

3. The method of authentication according to claim 2 , comprising, for said communications terminal and prior to the communications terminal obtaining a first reference value, a phase of determining a set of encryption parameters performed by the communication terminal comprising:
obtaining a Schnorr group (G) and a generator of this group (g);
obtaining the private key (z), said private key being an element of the group G;
computing, from the private key (z), of a public key Z such that Z is an exponentiation of the generator −g by the private key z, Z=gz.

4. The method of authentication according to claim 3 , wherein:
the act of obtaining the first reference value U[r1] implements the following computation: U[r1]=s2X−zs1;
the act of obtaining the second reference value U[r2] implements the following computation: U[r2]=s3Y−zs1.

5. The method of authentication according to claim 1 , comprising, for said user device, prior to the user device obtaining an authentication code, a phase of determining a set of encryption parameters performed by the user device comprising:
obtaining a Schnorr group (G) and a generator of this group (g);
obtaining the first private key (x), said private key being an element of the group G;
obtaining the second private key (y), said private key being an element of the group G;
computing, from the first private key (x), of a public key X such that X is an exponentiation of the generator g by the private key x, X=gx;
computing, from the first private key (y), of a public key Y such that Y is an exponentiation of the generator g by the private key y, Y=gy.

6. The method of authentication according to claim 5 , wherein:
the act of obtaining the authentication code S 1 implements the following computation: S 1 =H(m∥t), where ∥ is the concatenation operator;
the act of obtaining the first signature component S 2 implements the following computation: S2=(m∥t)·Z·x·S 1 ;
the act of obtaining the second signature component S 3 implements the following computation: S 3 =(M∥t)·Z·y·S 1 .

7. A user device comprising:
a general processing unit;
a memory;
a secured processing unit;
a secured memory; and
at least one reconfigurable circuit formed by the general processing unit and the secured processing unit for processing payment transactions with a communications terminal, said reconfigurable circuit configuring the user device to perform acts comprising:
calculating an authentication code S 1 from the message m, a piece of random data t and a hash function H;
calculating a first signature component S 2 from the message m, the random piece of data t, a public key Z of the user terminal, a first private key x of the user device and the authentication code S 1 ;
calculating a second signature component S 3 from the message m, the random piece of data t, the public key Z of the communications terminal, a second private key y of the user device and the authentication code S 1 ; and
transmitting, to the communications terminal, the authentication code S 1 , and the two signature components S 2 and S 3 .

8. A non-transitory computer readable medium comprising a computer program product stored thereon which comprises program code instructions for executing a method of authenticating at least one piece of data, when the instructions are executed by a user's device during a payment transaction taking place between a communications terminal and the user device of the type comprising authentication by the communications terminal of at least one message m generated by the user device, by using a near field communications wireless data link, the method comprising the following acts performed by the user device:
calculating an authentication code S 1 from the message m, a piece of random data t and a hash function H;
calculating a first signature component S 2 from the message m, the random piece of data t, a public key Z of the communications terminal, a first private key x of the user device and the authentication code S 1 ;
calculating a second signature component S 3 from the message m, the random piece of data t, the public key of Z of the communications terminal, a second private key y of the user device and the authentication code S 1 ; and
transmitting, to the communications terminal, the authentication code S 1 and the two signature components S 2 and S 3 .

Assignees

• Ingenico Group

Inventors

• Geraud Remi

Classifications

• G06Q20/352 Primary

  Contactless payments by cards · CPC title

• H04L9/3066

  involving algebraic varieties, e.g. elliptic or hyper-elliptic curves · CPC title

• H04L2209/72

  Signcrypting, i.e. digital signing and encrypting simultaneously · CPC title

• G06Q20/40975

  using encryption therefor · CPC title

• G06Q20/3823

  combining multiple encryption tools for a transaction · CPC title