Patent ID: 8824670

Claim:
Method of control of a device by a controller on the basis of a password; said method comprising the following steps, at the device or at the controller: /1/ determining on the basis of a random value r 1 a point P(X,Y) on an elliptic curve, in a finite field F q , q being an integer, of equation (1): E a,b ( x,y ): x 3 +ax+b=y 2 /2/ obtaining first and second parameters k and k′, such that P ( X,Y )= F ( k,k ′) where F is a surjective function of F q ×F q′ F q , /3/ encrypting the first and second parameters as a function of the password to obtain encrypted first and second parameters; and /4/ transmitting said encrypted first and second parameters to the controller; in which the function F is such that, regardless of z and z′ input elements of F q , F(z,z′) is a point on the elliptic curve, and the input elements do not satisfy equation (1).