Design and Implementation of Hierarchical Visual cryptography with Expansion less Shares
This work addresses secure image sharing for applications like data protection, but it appears incremental as it builds upon existing visual cryptography with hierarchical levels.
The paper tackles the problem of secret image sharing by introducing hierarchical visual cryptography with expansionless shares, which retains the original secret size across levels and removes the greying effect during decryption, resulting in a method that generates four shares where any three can reveal the secret without visual clues.
Novel idea of hierarchical visual cryptography is stated in this paper. The key concept of hierarchical visual cryptography is based upon visual cryptography. Visual cryptography encrypts secret information into two pieces called as shares. These two shares are stacked together by logical XOR operation to reveal the original secret. Hierarchical visual cryptography encrypts the secret in various levels. The encryption in turn is expansionless. The original secret size is retained in the shares at all levels. In this paper secret is encrypted at two different levels. Four shares are generated out of hierarchical visual cryptography. Any three shares are collectively taken to form the key share. All shares generated are meaningless giving no information by visual inspection. Performance analysis is also obtained based upon various categories of secrets. The greying effect is completely removed while revealing the secret Removal of greying effect do not change the meaning of secret.