# Computational Complexity of Modified Blowfish Cryptographic Algorithm on Video Data
###### Abstract  
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. title: **Applied and Computational Complexity of Modified Blowfish Cryptographic Algorithm on Video Data**  
**[PERSON] 1, 2022, 15, 373. [[https://doi.org/10.3390/a15100373](https://doi.org/10.3390/a15100373)]([https://doi.org/10.3390/a15100373](https://doi.org/10.3390/a15100373))**  
**Citation:** [PERSON]; [PERSON]; [PERSON]; [PERSON]. Computational Complexity of Modified Blowfish Cryptographic Algorithm on Video Data. _Algorithms_ **2022**, 15, 373.  
integrity, and availability. This is a security paradigm and guides companies to keep their secret data secure from illegal access and data exfiltration, often known as the CIA trio [2]. Privacy protection prevents unauthorized employees from gaining access to data; integrity ensures that the information is correct, complete, and dependable; and availability ensures that data are both available and accessible to meet specified requirements. Due to the obvious rapid development of diverse multimedia technology, a large number of audiovisual data are created and conveyed in the medical, advertisement, and military domains, which may contain sensitive information that should not be accessed by normal users or should only be partially disclosed to them [3; 4; 5]. Privacy and security have grown in importance while several encryption techniques have been employed to enable secure video transmission [6]. While a great number of multimedia encryption systems have been presented in the literature, and some have been implemented in real products, cryptanalytic work has revealed that most of the proposed multimedia encryption schemes have security issues and other flaws. Cryptography is the science of securing data, used to solve important security issues concerning confidentiality, integrity, and authentication [7; 8]. Its goal is to safely send sensitive information via vulnerable networks such as the internet [9]. To prevent others from accessing an encrypted message, the sender only discloses the decoding process to the intended recipients.