# Computational Complexity of Modified Blowfish Cryptographic Algorithm on Video Data
## 2 Materials and Methods  
This research compares the Blowfish algorithm with the modified Blowfish algorithm to assess the security, effectiveness, and overall performance of both cryptographic algorithms. The S-Box preparation, sub-key creation, and encryption are the three primary aspects of Blowfish. This research adjusted the structure of the F-function by utilizing fewer S-Boxes to improve the existing Blowfish method. The modified Blowfish encryption algorithm was implemented using the Blowfish library in Python 3.8 version, Flask micro web framework, and JavaScript Programming language. All development, testing, and design processes were implemented on a windows 10 operating system of intel core i5 (7 th generation) with processing power of 2.7 GHz CPU with 8 GB RAM. The study was evaluated in three stages: the time complexity of the Blowfish with respect to video data, the time complexity of the modified Blowfish algorithm, the security performance of the Blowfish algorithm using avalanche effects, and the performance evaluation of Blowfish and the modified Blowfish algorithm when applied to video data. Throughput is another metric that may be used to evaluate Blowfish and the modified Blowfish algorithm's performances. \[\text{Throughput}=\text{Data (in kb)}/(\text{Process end time}-\text{Process start time}) \tag{1}\]  
The final parameter used for the performance evaluation is the avalanche effect of the encryption algorithms. This parameter will be used to test the security levels of Blowfish and modified Blowfish algorithms. The behavior of mathematical functions employed in encryption is described by the \"avalanche effect.\" One of the desirable elements of any encryption technique is the avalanche effect. The cipher text should change drastically if \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**S/N** & **Authors** & **Algorithms** & **Parameter** & **Outcome** & **Gap** \\ \hline
3 & [PERSON] and [PERSON] [18] & Modified Blowfish & Text Data & The study captures the runtime of encrypting the plaintext. & The study did not specify how the algorithm was modified \\  & [PERSON], [PERSON], and [PERSON] [19] & Blowfish and Steganography & Text Data and Audio File & The study encrypts text data using Blowfish and embeds the cipher text in an audio file using discrete wavelet transform The algorithm seems to be better for IoT devices in terms of execution time, memory usage, throughput, power consumption, and security & The method used is secure; however, it is not time efficient. \\  & & & & & \\
5 & [PERSON] and [PERSON] [20] & Blowfish Algorithm & Text Data on IoT devices & The algorithm block size and key length were reduced because it was used on devices with limited resources. \\  & & & & & \\
6 & [PERSON] and [PERSON] [21] & Modified Blowfish & Image Data & The difficulty of the modified algorithm was applied to encrypt the image. & The complexity of the modified algorithm was greatly increased. \\  & & & & & \\
7 & [PERSON], [PERSON], and [PERSON] [22] & Blowfish-128 & Text Data & The modifications improved performance and execution time & The complexity and diffusion of the algorithm were increased. \\  & & & Encryption quality, correlation & The study used XOR to update the F function so as & The study did not specify the type of parameter used for either text, image, or audio data. \\
8 & [PERSON], [PERSON], and [PERSON] [23] & Improved Blowfish & Text and Image & Blowfish is better for text data while AES is better for image data. & The experiment was simulated on a system with limited memory space. \\  & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._the plain text or key is changed slightly. This characteristic is termed the avalanche effect. In simple words, it quantifies the impact of a slight change in plain text or the key on the ciphertext.