Method for securely transmitting a secret data to a user of a terminal

A method for securely transmitting a secret data from a user to a secure processor, comprising:

• securely displaying a secret challenge to a user by a user terminal, the displayed secret challenge being secured by:
• receiving, by the user terminal from a secure processor, a software component configured to generate sets of pixels, each set of pixels having a visible state and an invisible state, of which respective probabilities in the visible state or the invisible state being less than 100%;
• executing, by the user terminal, the software component at a rate corresponding to a frame display refresh rate to generate the sets of pixels at the frame display refresh rate;
• inserting the sets of pixels generated by each execution of the software component into one respective image frame;
• and
• activating display of the image frames at the frame display refresh rate, each image frame including information corresponding to the secret challenge and which is specific to the software component and machine non-recognizable as being formed of the sets of pixels, the information becoming visibly recognizable to a user at the frame display refresh rate based on a human visual system;
• acquiring data input by the user in relation with the displayed secret challenge;
• transmitting, by the user terminal, the data input by the user to the secure processor, and
• determining, by the secret processor, a secret data known by the user from the data input by the user in view of the secret challenge, the secret challenge being such that the secret data is determinable from the data input by the user only in view of the secret challenge,
• wherein the software component is encoded as a circuit including:
• circuit inputs, circuit outputs, logic gates and wires, each logic gate having two inputs and one output, each wire having a first end connected to one of the circuit inputs or to the one output of one of the logic gates and a second end connected to one of the two inputs of one of the logic gates or to one of the circuit outputs;
• and
• a respective generation circuit for each generated set of pixels, each generation circuit including a first logic gate and a set of second logic gates, the first logic gate combines a first input data to a randomly selected second data, and provides an output data to a first input of each of the second logic gates, a second input of each of the second logic gates receiving a third input data, each of the outputs of the second logic gates providing a respective pixel value of one pixel of the set of pixels.

A user terminal, comprising:

• a processor;
• and
• a memory for storing information to be executed by the processor, the processor is configured to:
• receive a software component configured to generate sets of pixels having a respective probability lower than 100% to be in a visible state or an invisible state;
• execute the software component, at a rate corresponding to a frame display refresh rate, to generate the sets of pixels at the frame display refresh rate;
• insert the sets of pixels, generated by each execution of the software component, into one respective image frame;
• and
• activate display of the image frames at the frame display refresh rate, each of the image frames including information which is specific to the software component and machine non-recognizable as being formed of the sets of pixels, the information becoming visibly recognizable to a user at the frame display refresh rate based on a human visual system,
• wherein the software component is encoded as a circuit including:
• circuit inputs, circuit outputs, logic gates and wires, each logic gate having two inputs and one output, each wire having a first end connected to one of the circuit inputs or to the one output of one of the logic gates and a second end connected to one of the two inputs of one of the logic gates or to one of the circuit outputs;
• and
• a respective generation circuit for each generated set of pixels, each generation circuit including a first logic gate and a set of second logic gates, the first logic gate combines a first input data to a randomly selected second data, and provides an output data to a first input of each of the second logic gates, a second input of each of the second logic gates receiving a third input data, each of the outputs of the second logic gates providing a respective pixel value of one pixel of the set of pixels.

A secure element, comprising:

• a secure processor configured to:
• generate a software component configured to generate sets of pixels having a respective probability lower than 100% to be in a visible state or an invisible state, the software component being executed at a rate corresponding to a frame display refresh rate to generate the sets of pixels at the frame display refresh rate, the sets of pixels generated by each execution of the software component being inserted into one respective image frame, each image frame including information which is specific to the software component and machine non-recognizable as being formed of the sets of pixels, the information becoming visibly recognizable to a user when the image frames are displayed at the frame display refresh rate based on a human visual system;
• and
• transmit the software component to a user terminal,
• wherein the software component is encoded as a circuit including:
• circuit inputs, circuit outputs, logic gates and wires, each logic gate having two inputs and one output, each wire having a first end connected to one of the circuit inputs or to the one output of one of the logic gates and a second end connected to one of the two inputs of one of the logic gates or to one of the circuit outputs;
• and
• a respective generation circuit for each generated set of pixels, each generation circuit including a first logic gate and a set of second logic gates, the first logic gate combines a first input data to a randomly selected second data, and provides an output data to a first input of each of the second logic gates, a second input of each of the second logic gates receiving a third input data, each of the outputs of the second logic gates providing a respective pixel value of one pixel of the set of pixels.

A non-transitory computer-readable medium carrying code portions which, when carried out by a computer, configure the computer to carry out operations of:

• receive a software component configured to generate sets of pixels, each set of pixels having a visible state and an invisible state, of which respective probabilities in the visible state or the invisible state being less than 100%;
• execute the software component at a rate corresponding to a frame display refresh rate to generate the sets of pixels at the frame display refresh rate;
• insert the sets of pixels generated by each execution of the software component into one respective image frame;
• and
• activate display of the image frames at the frame display refresh rate, each image frame including information which is specific to the software component and machine non-recognizable as being formed of the sets of pixels, the information becoming visible recognizable to a user at the frame display refresh rate based on a human visual system,
• wherein the software component is encoded as a circuit including:
• circuit inputs, circuit outputs, logic gates and wires, each logic gate having two inputs and one output, each wire having a first end connected to one of the circuit inputs or to the one output of one of the logic gates and a second end connected to one of the two inputs of one of the logic gates or to one of the circuit outputs;
• and
• a respective generation circuit for each generated set of pixels, each generation circuit including a first logic gate and a set of second logic gates, the first logic gate combines a first input data to a randomly selected second data, and provides an output data to a first input of each of the second logic gates, a second input of each of the second logic gates receiving a third input data, each of the outputs of the second logic gates providing a respective pixel value of one pixel of the set of pixels.