Computational Complexity of Modified Blowfish Cryptographic Algorithm on Video Data

Background: The technological revolution has allowed users to exchange data and information in various fields, and this is one of the most prevalent uses of computer technologies. However, in a world where third parties are capable of collecting, stealing, and destroying information without authorization, cryptography remains the primary tool that assists users in keeping their information secure using various techniques. Blowfish is an encryption process that is modest, protected, and proficient, with the size of the message and the key size affecting its performance. Aim: the goal of this study is to design a modified Blowfish algorithm by changing the structure of the F function to encrypt and decrypt video data. After which, the performance of the normal and modified Blowfish algorithm will be obtained in terms of time complexity and the avalanche effect. Methods: To compare the encryption time and security, the modified Blowfish algorithm will use only two S-boxes in the F function instead of the four used in Blowfish. Encryption and decryption times were calculated to compare Blowfish to the modified Blowfish algorithm, with the findings indicating that the modified Blowfish algorithm performs better. Results: The Avalanche Effect results reveal that normal Blowfish has a higher security level for all categories of video file size than the modified Blowfish algorithm, with 50.7176% for normal Blowfish and 43.3398% for the modified Blowfish algorithm of 187 kb; hence, it is preferable to secure data and programs that demand a high level of security with Blowfish. Conclusions: From the experimental results, the modified Blowfish algorithm performs faster than normal Blowfish in terms of time complexity with an average execution time of 250.0 ms for normal Blowfish and 248.4 ms for the modified Blowfish algorithm. Therefore, it can be concluded that the modified Blowfish algorithm using the F-structure is time-efficient while normal Blowfish is better in terms of security.publishedVersio

Blowfish Privacy: Tuning Privacy-Utility Trade-offs using Policies

Privacy definitions provide ways for trading-off the privacy of individuals in a statistical database for the utility of downstream analysis of the data. In this paper, we present Blowfish, a class of privacy definitions inspired by the Pufferfish framework, that provides a rich interface for this trade-off. In particular, we allow data publishers to extend differential privacy using a policy, which specifies (a) secrets, or information that must be kept secret, and (b) constraints that may be known about the data. While the secret specification allows increased utility by lessening protection for certain individual properties, the constraint specification provides added protection against an adversary who knows correlations in the data (arising from constraints). We formalize policies and present novel algorithms that can handle general specifications of sensitive information and certain count constraints. We show that there are reasonable policies under which our privacy mechanisms for k-means clustering, histograms and range queries introduce significantly lesser noise than their differentially private counterparts. We quantify the privacy-utility trade-offs for various policies analytically and empirically on real datasets.Comment: Full version of the paper at SIGMOD'14 Snowbird, Utah US

Optimasi Metode Blowfish untuk Mengamankan Password pada Kriptografi

Berkembangnya ilmu komputerisasi, isu mengenai keamanan data baik dalam bentuk file maupun password menjadi sangat penting. Untuk menjaga keamanan pada data tersebut, makadikenal salah satu teknik yaitu kriptografi. Adapun algoritma yang digunakan adalah Algoritma Blowfish. Blowfish merupakan algoritma yang aman, sederhana, kuat dan cepat denganmenggunakan 16 putaran, dengan blok cipher 64-bit yang merupakan panjang dari kunci variabel. Keunggulan blowfish yaitu mempunyai dua bagian yaitu perluasan kunci atau keyexpansion dan enkripsi data. Blowfish disebut juga dengan algoritma kunci simetrik cipher blok yang dikenal dengan istilah “OpenPGP.Cipher.4”. Pesan tanpakunci yang dienkripsi oleh blowfish belum bisa dibongkar oleh kriptanalis sampai sekarang. Hasil dari implementasi blowfish ini menunjukkan bahwa aplikasi dapat menjalankan fungsipada proses enkripsi dan dekripsi data dengan baik dalam mengamankan password dalam ranah kunci heksa string dan alfabet

Dynamic Selection of Symmetric Key Cryptographic Algorithms for Securing Data Based on Various Parameters

Most of the information is in the form of electronic data. A lot of electronic data exchanged takes place through computer applications. Therefore information exchange through these applications needs to be secure. Different cryptographic algorithms are usually used to address these security concerns. However, along with security there are other factors that need to be considered for practical implementation of different cryptographic algorithms like implementation cost and performance. This paper provides comparative analysis of time taken for encryption by seven symmetric key cryptographic algorithms (AES, DES, Triple DES, RC2, Skipjack, Blowfish and RC4) with variation of parameters like different data types, data density, data size and key sizes.Comment: 8 pages, 4 figures, Fifth International Conference on Communications Security & Information Assurance (CSIA 2014) May 24~25, 2014, Delhi, Indi

Kombinasi Steganografi Bit Matching dan Kriptografi Playfair Cipher, Hill Cipher dan Blowfish

Abstract - To secure data, cryptographic techniques are needed, but many cryptographic methods are vulnerable that require attacks. But not with the Blowfish method which includes a symmetric key algorithm that has the same key to encrypt and decrypt data. The blowfish algorithm is a block cipher and until now. Blowfish is still superior in the field of strength endurance will receive attacks from outside by people who are not responsible. In this study, a test will be carried out to see the time used to make a suitable steganographic combination and to combine several cryptographic methods such as Playfair, hill cipher, and blowfish. The average embedding average 28.275 seconds embedding extraction 27.843 seconds and for imaging the average embedding 13.0208 seconds and extraction 12.7986 seconds.Keywords  -   Steganography, Playfair, Hill Cipher, Blowfish. Bit Matching Abstrak - Untuk melakukan pengamanan data dibutuhkan tekhnik kriptografi akan tetapi sudah banyak metode-metode kriptografi yang rentan terkena serangan. Namun tidak dengan metode Blowfish yang termasuk algoritma kunci simetris yang memiliki kunci yang sama untuk mengenkripsi dan mendekripsi suatu data. Algoritma Blowfish merupakan cipher blok dan sampai saat ini algoritma Blowfish masih unggul dibidang ketahanannya yang kuat akan menerima serangan dari luar oleh orang-orang yang tidak bertanggung jawab. Pada penelitian kali ini akan dilakukan pengujian untuk melihat waktu yang dipakai untuk melakukan kombinasi steganografi bit matching serta mengkombinasikan beberapa metode kriptografi seperti playfair, hill cipher dan blowfish. Hasilnya ialah untuk citra hitam putih diperoleh waktu rata-rata embedding 28.275 detik ekstraksi 27.843 detik dan untuk citra berwarna waktu rata-rata embedding 13.0208 detik dan ekstraksi 12,7986 detik.Kata Kunci - Steganografi, Playfair, Hill Cipher, Blowfish, Bit Matching

STUDI DAN PERBANDINGAN ALGORITMA IDEA DAN ALGORITMA BLOWFISH

Algoritma International Data Encryption Algorithm (IDEA) dan Algoritma Blowfish adalah algoritma kriptografi simetris dengan kategori cipher blok. Kedua algoritma ini beroperasi dalam bentuk blok bit, dengan ukuran blok sebesar 64 bit. Kedua algoritma ini juga dikenal sangat tangguh dalam mengamankan informasi. Studi dan perbandingan antara algoritma IDEA dan algoritma Blowfish dilakukan untuk membandingkan kinerja algoritma IDEA dan Blowfish dalam hal kecepatan proses dan penggunaan memori pada saat proses enkripsi dan dekripsi suatu file. Untuk dapat membandingkan kinerja algoritma IDEA dan algoritma Blowfish, maka penulis membangun sebuah program enkripsi dan dekripsi file dengan menggunakan bahasa pemrograman JAVA. Dari hasil uji coba program terhadap sampel file teks, file dokumen, file image, file audio, dan file video, terlihat bahwa algoritma IDEA lebih cepat dari algoritma Blowfish dan pemakaian memori kedua algoritma relatif sama