ABSTRACT

In this paper, variable block length based character/bit level transformation has been proposed for encryption and decryption, where a block of characters /few bits has taken into account. The originated text is transformed into decimal values and passed to encoder module. In this module values are cluttered using binary operations present in most systems with keys. This routine is based on feistel iteration using large number of rounds for security justification to certain intensity and passed to the security module. This module performs conversion of values into octal base values and then padded with a vector. When compared with other encryption schemes it provides more security even though keys are revealed. Since, one parameter namely vector ai alone been kept secret. The receiver passes the received cipher text to security module and yields the cipher decimal values. These values are transformed into a form of originated text.