Security Enhancement of Blowfish Block Cipher
Rajan Patel, Pariza Kamboj · Communications in computer and information science · 2016
Cryptography is the first line of defense to protect the data from intruder. Symmetric cryptography and asymmetric cryptography are two cryptographic based algorithms that serve the security goals: confidentiality, availability, authentication and integrity. Asymmetric algorithms are known as public key cryptography that uses two keys: one public key for encryption and second private for decryption while symmetric algorithms are known as private key cryptography that uses the single private key for encryption and decryption. Symmetric algorithms are less costly compare to asymmetric algorithms. Normally asymmetric algorithms are used to distribute the secret sharing key of symmetric algorithm and symmetric algorithms are used for data encryption. Wide range of symmetric algorithms exists like Blowfish, DES, 3DES, AES, Twofish, RC2, RC5, CAST-128, and IDEA. Among these symmetric algorithms, AES and Blowfish give better throughput compare to other symmetric ciphers. In this article, we proposed the scheme to enhance the Blowfish block cipher security. In proposed scheme, total numbers of Blowfish rounds are altered by skipping few Blowfish rounds using round key. As a result, proposed scheme increase additional Blowfish cipher security against brute-force attack apart from minimum to maximum size of Blowfish key. In addition to that the proposed scheme also decreases encryption and decryption execution time of Blowfish cipher.