Proposed FPGA based technique considers a message as a binary string on which ROBAST is applied. A block of n-bits is taken as an input stream, where n ranges from 8 to 256 – bit, then ROBAST is applied in each block to generate intermediate stream, any one intermediate stream is considered as a cipher text. The same operation is performed repeatedly on various block sizes. It is a kind of block cipher and symmetric in nature hence decoding is done in similar manner. This paper also presents an efficient hardware realization of the proposed technique using state-of-the-art Field Programmable Gate Array (FPGA). The technique is also coded in C programming language and Very High Speed Integrated Circuit Hardware Description Language (VHDL). Various results and comparisons have been performed against industrially accepted RSA and TDES. A satisfactory results and comparisons are found.