Date Added: May 2012
In this paper, the authors analyze application of Selective Encryption with Automatic Variable Key (AVK) for text based documents in Koyama Public Key Cryptosystem (PKC). In this paper, a new robust and simple PKC based singular cubic curve cryptosystem over the ring Zn, using selective encryption with Automatic Variable Key (AVK), is proposed. In the proposed algorithm, selected parts of text document are encrypted/decrypted using any public key cryptosystem e.g. RSA algorithm based singular cubic curve with AVK approach. The key is configured every time as Automatic Variable Key.