Coloured visual cryptography using fixed size meaningful share

Abstract

Visual cryptography is a useful technique for sharing secret information on a public channel. One of the major strengths of visual cryptography is that the hidden secret, once extracted, can be visualized by the human eye without going through complex computations for decoding. In this paper, a novel visual cryptography scheme is offered that encodes a colour secret image into two meaningful shares. Our proposal provides improvements that allow the size of the meaningful share to stay fixed. This keeps the image from the attention of possible attackers during the transmission. In addition, our new scheme provides three patterns which produce better visual equality for each meaningful share. It also allows a user to produce a different secret image/share with the desired visual effects. Experimental results have demonstrated the practicability and effectiveness of our new scheme.

Keywords:

• visual secret sharing
• visual cryptography
• halftone technique
• meaningful share

2000 AMS Subject Classification :

• 68U10