Data security has always been important in all aspects of life. Data may contain several form of information that we want to secure from any unauthorized access. It can be all the more important as technology continues to control various operations in our day to day life Reprogrammable devices are highly attractive options for hardware implementations of encryption algorithms as they provide cryptographic algorithm agility, physical security, and potentially much higher performance, therefore this paper investigates a hardware design to efficiently implement a special type block ciphers in VHDL and its comparative analysis in different parameter variation. This hardware design is applied to the new secret and variable size key block cipher called Blowfish designed to meet the requirements of the previous known standard and to increase security and to improve performance. The proposed algorithm will be used a variable key size.