Secure data transfer on a handheld communications device
A handheld communications device comprises a display device, and a data processor that is in communication with the display device. The data processor is configured to generate an encryption key, and vary a visual output of the display device in accordance with a bit sequence of the encryption key. The varying visual output comprises a sequence of colors rendered on the display device and/or brightness levels output by the display device.
1. A method of initiating secure communications using a portable authenticator, the portable authenticator comprising a light sensor and a data processor in communication with the light sensor, the method comprising:
detecting a sequence of colours and light brightness levels over a period of time via the light sensor;
recovering a bit sequence from the sequence of colours and light brightness levels via the data processor;
generating a first encryption key from the bit sequence via the data processor;
receiving a temporary encryption key via a wireless interface of the portable authenticator;
grouping bits of the temporary encryption key into a bit grouping based on colours and brightness sequence levels;
computing a public encryption key from the temporary encryption key and the first encryption key; and
saving the public encryption key in the memory.
2. The method according to claim 1 , wherein:
the sequence of colours and light brightness levels includes varying intensities of light and a sequence of brightness levels; and
the bit sequence is recovered from the sequence of brightness levels.
3. The method according to claim 2 , wherein:
the sequence of colours and light brightness levels comprises a sequence of brightness levels and a sequence of colours contemporaneously with the sequence of brightness levels; and
the bit sequence is recovered from the sequence of brightness levels and the sequence of colours.
4. The method according to claim 1 , wherein:
the sequence of colours and light brightness levels includes varying intensities of light and a sequence of colours; and
the bit sequence is recovered from the sequence of colours.
5. The method according to claim 1 , wherein:
the sequence of colours and light brightness levels has a varying background colour, which is detected from over the period of time.
6. The method according to claim 1 , wherein:
the sequence of colours and light brightness levels has a varying predominant colour in an image, which is detected from over the period of time.
7. The method according to claim 1 , wherein:
the sequence of colours and light brightness levels has a varying intensity controlled by varying a display light, which is detected from over the period of time.
8. The method according to claim 1 , wherein:
the bit grouping is a di-bit grouping; and
the sequence of colours and light brightness levels comprises four brightness levels.
9. A portable authenticator comprising:
a light sensor;
a wireless interface;
a memory; and
a data processor in communication with the light sensor, the data processor being configured to:
recover a bit sequence from a sequence of colours and light brightness levels over a period of time detected at the light sensor; and
generate a first encryption key from the bit sequence;
the data processor being further configured to
communicate with the wireless interface and the memory;
receive a temporary encryption key via the wireless interface;
group bits of the temporary encryption key into a bit grouping based on colours and brightness sequence levels;
compute a public encryption key from the temporary encryption key and the first encryption key; and
save the public encryption key in the memory;
and
the data processor being further configured to
receive incoming data via the wireless interface;
decrypt the incoming data with the public encryption key into decrypted data;
compare the decrypted data with reference data stored in the memory;
generate an authorization message based on an outcome of the comparing; and
transmit the authorization message via the wireless interface.
10. The portable authenticator according to claim 9 , wherein:
the sequence of colours and light brightness levels includes varying intensities of light and a sequence of brightness levels; and
the data processor is configured to recover the bit sequence from the sequence of brightness levels.
11. The portable authenticator according to claim 10 , wherein:
the sequence of colours and brightness levels comprises a sequence of brightness levels and a sequence of colours contemporaneously with the sequence of brightness levels; and
the data processor is configured to recover the bit sequence from the sequence of brightness levels and the sequence of colours.
12. The portable authenticator according to claim 9 , wherein:
the sequence of colours and light brightness levels includes varying intensities of light and a sequence of colours; and
the data processor is configured to recover the bit sequence from the sequence of colours.
13. The portable authenticator according to claim 9 , wherein:
the sequence of colours and light brightness levels has a varying background colour, which is detected from over the period of time.
14. The portable authenticator according to claim 9 , wherein:
the sequence of colours and light brightness levels has a varying predominant colour in an image, which is detected from over the period of time.
15. The portable authenticator according to claim 9 , wherein:
the sequence of colours and light brightness levels has a varying intensity controlled by varying a display light, which is detected from over the period of time.
16. The portable authenticator according to claim 9 , wherein:
the bit grouping is a di-bit grouping; and
the sequence of colours and light brightness levels comprises four brightness levels.