A Novel Approach to Key Management Using Visual Cryptography

Received: 12 May 2019 Accepted: 6 August 2019 Visual Cryptography encrypts the secret or key into ‘n’ shares or portions and distributes them to a group of ‘n’ participants. The secret is recovered only when shares of all the participants in the group are stacked upon one another depending on the method used. This technique eliminates complex computations during decryption. It uses simple OR or XOR Boolean operations. Once the secret is revealed, it is no more a secret. So, a new secret acts as a key, that is to be again shared confidentially. The same process is performed and new shares are generated and distributed. The generation and distribution of shares must be done every time when a new secret or a combinational key is shared. In this paper, a trusted third party generates the shares and distributes it to the group of participants. It also generates an extra share for itself. To reveal the secret, the third party’s share is also used along with other participants shares. Every time when the secret is to be changed, the third party regenerates its share only, instead of generating shares for all participants. This method reduces the overhead of regeneration and redistribution of shares to all participants with every change of the secret or key. This method of key management also retains the perfect contrast and security. The OR based method leads to noise during recovery. XOR based operations during recovery recovers lossless image. So, XOR operation is more preferable during recovery of the secret.