A Lossless Tagged Visual Cryptography SchemeAbstract: -Visual Cryptography is based on cryptography where n images are encoded in a way that only the human visual system can decrypt the hidden message without any cryptographic computations when all shares are stacked together. As one of the most efficient multi-secret visual cryptography (MVC) schemes. The tagged visual cryptography (TVC) is capable of hiding tag images into randomly selected shares. However, the encoding processes of TVC and other MVC schemes bring distortion to shares, which denitely lowers the visual quality of the decoded secret image. This letter proposes an extended TVC scheme, named as lossless TVC (LTVC). Specically, lossless means that the proposed LTVC scheme encodes the tag image without affecting the rebuilt secret image. A multi-secret sharing scheme is a protocol to share m arbitrarily related secrets s 1,..., s m among a set of participants. Pixel expansion and the quality of the reconstructed secret image has been a major issue of visual secret sharing (VSS) schemes. A number of probabilistic VSS schemes with minimum pixel expansion have been proposed for black and white (binary) secret images. This paper presents a probabilistic (2, 3)-SS scheme for gray scale images. Its pixel expansion is larger in size but the quality of the image is perfect when its reconstructed. The construction of the shadow images (transparent shares) is based on the binary OR operation

Existing System:- Transmission times for documents encrypted using public key cryptography are significantly slower then symmetric cryptography. In fact, transmission of very large documents is prohibitive. The key sizes must be significantly larger than symmetric cryptography to achieve the same level of protection. Public key cryptography is susceptible to impersonation attacks

Proposed System:- The proposed LTVC scheme encodes the tag image without affecting the rebuilt secret image We propose a tagged VC (TVC) scheme in which more secret images can be revealed by the folding up operation. we propose the probabilistic LTVC (P-LTVC) to solve the potential security problem of LTVC The superiority of the proposed scheme is experimentally veried.

Hardware Requirements:-

SYSTEM: Pentium IV 2.4 GHz HARD DISK: 40 GB RAM: 256 MB

Software Requirements:- Operating system : Windows XP Professional IDE : Microsoft Visual Studio .Net 2008 Database : Sql server Coding Language: C#.NET