Authentication device, system and method

An authentication device comprising:

• a light sensor;
• and
• a transmitter;
• wherein the authentication device is configured to:
• receive a unique identifier from a user device by sensing, with the light sensor, a visual element encoding the unique identifier that is displayed on a display of the user device;
• transmit, to a server, the unique identifier;
• receive, from the server, a cryptographic key corresponding to the unique identifier;
• transmit, with the transmitter to the user device, the cryptographic key for decryption of an electronic message corresponding to the unique identifier;
• receive a sender's identification by scanning a second visual element encoding the sender's identification that is displayed on the display of the user device;
• and
• transmit, to the server, the sender's identification.

A computer-implemented method for encrypting an electronic message, comprising:

• receiving a receiver's identification at an authentication device from a user device by sensing, with a light sensor of the authentication device, a visual element of the electronic message that is displayed on a display of the user device, the visual element encoding the receiver's identification;
• generating, at the authentication device, a cryptographic key and a unique identifier;
• transmitting, by the authentication device, the cryptographic key and the unique identifier to the user device for encryption of the electronic message;
• transmitting, by the authentication device and over a secure channel, the cryptographic key, the unique identifier and the receiver's identification to a server;
• receiving, by the user device, the cryptographic key and the unique identifier from the authentication device;
• encrypting, by the user device and using the cryptographic key, a payload of the electronic message to generate an encrypted electronic message;
• inserting, by the user device, a second visual element into the encrypted electronic message, the second visual element encoding the unique identifier;
• and
• transmitting, by the user device, the encrypted electronic message to a receiver associated with the receiver's identification.

A computer-implemented method for decrypting an electronic message, comprising:

• (a) receiving a unique identifier from a user device by sensing, with a light sensor of an authentication device, a visual element of the electronic message that encodes the unique identifier and which is displayed on a display of the user device;
• (b) transmitting the received unique identifier, by the authentication device, over a secure channel to a server;
• (c) receiving, by the authentication device, a cryptographic key over the secure channel from the server, the cryptographic key corresponding to the unique identifier;
• (d) transmitting, by the authentication device, the cryptographic key to the user device for decryption of the electronic message;
• and
• before operation a) or operation b):
• receiving, via a user input device of the authentication device, biometric information and/or a secret code from a user;
• determining, by the authentication device, whether the biometric information and/or the secret code corresponds to an authorized user;
• and
• in the negative, aborting the decryption of the electronic message.