## 4 Experimental Results and Discussion
### Performance Comparison of NTSA with TEA, XTEA and XXTEA
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**KEY SIZE** & \multicolumn{4}{c}{**DECRYPTION TIME (in milliseconds)**} \\ \hline
**(IN BITS)** & **TEA** & **XTEA** & **BLOCK TEA (OXTEA)** & **NTSA** \\ \hline
32 & 0.124 & 0.281 & 0.146 & 0.068 \\
48 & 0.136 & 0.257 & 0.15 & 0.087 \\
64 & 0.123 & 0.214 & 0.152 & 0.088 \\
96 & 0.123 & 0.259 & 0.158 & 0.091 \\
128 & 0.125 & 0.276 & 0.179 & 0.090 \\
160 & 0.113 & 0.267 & 0.155 & 0.101 \\
192 & 0.126 & 0.26 & 0.159 & 0.119 \\
240 & 0.123 & 0.259 & 0.157 & 0.119 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Time for file size 0.95 kB. definitely enable IoT devices with varying computational and storage capabilities to efficiently and securely transmit text files through the network. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**KEY SIZE** & \multicolumn{4}{c}{**ENCRYPTION TIME (in milliseconds)**} \\ \hline
**(IN BITS)** & **TEA** & **XTEA** & **BLOCK TEA (XXTEA)** & **NTSA** \\ \hline
32 & 2.253 & 4.459 & 2.339 & 1.772 \\
48 & 1.883 & 3.734 & 2.111 & 1.789 \\
64 & 1.933 & 3.349 & 2.485 & 1.812 \\
96 & 2.812 & 4.856 & 2.246 & 1.856 \\
128 & 2.209 & 5.207 & 2.224 & 1.825 \\
160 & 2.925 & 3.687 & 2.731 & 1.887 \\
192 & 1.869 & 4.562 & 1.958 & 1.662 \\
240 & 1.989 & 4.213 & 2.43 & 1.912 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Time for file size 26.7 kB. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**KEY SIZE** & \multicolumn{4}{c}{**ENCRYPTION TIME (in milliseconds)**} \\ \hline
**(IN BITS)** & **TEA** & **XTEA** & **BLOCK TEA (XXTEA)** & **NTSA** \\ \hline
32 & 1.173 & 2.287 & 1.649 & 1.009 \\
48 & 1.178 & 2.572 & 1.393 & 1.010 \\
64 & 1.248 & 2.089 & 1.178 & 1.006 \\
96 & 1.208 & 2.32 & 1.502 & 1.10 \\
128 & 1.067 & 2.301 & 1.534 & 1.04 \\
160 & 1.137 & 2.608 & 1.076 & 1.03 \\
192 & 1.39 & 2.327 & 1.148 & 1.11 \\
240 & 1.439 & 2.866 & 1.413 & 1.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Time for file size 12.2 kB. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**KEY SIZE** & \multicolumn{4}{c}{**ENCRYPTION TIME (in milliseconds)**} \\ \hline
**(IN BITS)** & **TEA** & **XTEA** & **BLOCK TEA (XXTEA)** & **NTSA** \\ \hline
32 & 1.177 & 2.249 & 1.641 & 1.08 \\
48 & 1.195 & 2.572 & 1.396 & 1.083 \\
64 & 1.241 & 2.084 & 1.179 & 1.112 \\
96 & 1.226 & 2.299 & 1.477 & 1.117 \\
128 & 1.029 & 2.265 & 1.583 & 1.020 \\
160 & 1.093 & 2.645 & 1.074 & 1.025 \\
192 & 1.363 & 2.278 & 1.163 & 1.155 \\
240 & 1.402 & 2.827 & 1.414 & 1.388 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Decryption time for file size 12.2 kB. From the results presented in Tables 2-11, it is very evident that the NTSA algorithm give better performance compared to all the existing algorithms with variable file sizes and key sizes. NTSA gave much lower encryption and decryption times for variable size text files using multiple key sizes in IoT networks. This is due to the simple and efficient design of NTSA. One of the most important features of NTSA is that it provides enhanced security to all the applications in IoT devices with lower encryption and decryption times. Thus, the proposed approach NTSA can be used for efficient and secure transfer of text files between devices in IoT networks.