Reverse Circle Cipher for personal and network security

Many data encryption techniques have been employed to ensure both personal data security and network security. But few have been successful in merging both under one roof. The block cipher techniques commonly used for personal security such as DES and AES run multiple passes over each block making them ineffective for real time data transfer. Also, ciphers for network security such as Diffie-Hellman and RSA require large number of bits. This paper suggests a simple block cipher scheme to effectively reduce both time and space complexities and still provide adequate security for both security domains. The proposed Reverse Circle Cipher uses `circular substitution' and `reversal transposition' to exploit the benefits of both confusion and diffusion. This scheme uses an arbitrarily variable key length which may even be equal to the length of the plaintext or as small as a few bits coupled with an arbitrary reversal factor. This method of encryption can be utilized within stand alone systems for personal data security or even streamed into real time packet transfer for network security. This paper also analyses the effectiveness of the algorithm with respect to the size of the plaintext and frequency distribution within the ciphertext.