## 4 Experimental Results and Discussion
### Avalanche Effect  
The avalanche effect is the property wherein a very small change in input results in significant changes on the output. An encryption algorithm is considered good if a one-bit change in key results in significant changes in the cipher text. With reference to the avalanche effect, we compared the strength of NTSA and TEA algorithms. Experiment 1: an encryption was performed for NTSA and TEA algorithms using keys with varying key sizes of 48, 64 and 128 bits and same plaintext. Then one bit was changed on the key and the experiment was repeated. It is observed that for every 64-bit block, a one-bit change in key resulted in significant changes on the cipher text. Drastic changes were observed for the NTSA algorithm when compared to TEA. Figure 7 shows, for every 64-bit block, a change in one bit of the key with various key sizes and the corresponding change in cipher text for NTSA and TEA. From Figure 7, it is very evident that when a bit in the key was changed, the cipher text generated using NTSA algorithm had more drastic change than the cipher text created using TEA. This shows the increased security offered by the NTSA algorithm compared to TEA. Experiment 2: an encryption was performed for NTSA and TEA algorithms using keys with varying key sizes 48, 64 and 128 bits. Then one bit was changed on the plaintext and the experiment is repeated. It was observed that for every 64-bit block, one-bit change in plaintext resulted in significant changes on the cipher text. Drastic changes were observed for the NTSA algorithm when compared to TEA. Experiment 3: an encryption was performed for NTSA and TEA algorithms using keys with varying key sizes 48, 64 and 128 bits. Then one bit was changed on the plaintext and the experiment is repeated. It was observed that for every 64-bit block, one-bit change in plaintext resulted in significant changes on the cipher text. Drastic changes were observed for the NTSA algorithm when compared to TEA. Experiment 4: an encryption was performed for NTSA and TEA algorithms using keys with varying key sizes 48, 64 and 128 bits. Then one bit was changed on the plaintext and the experiment is repeated. It was observed that for every 64-bit block, one-bit change in plaintext resulted in significant changes on the cipher text. Drastic changes were observed for the NTSA algorithm when compared to TEA. Experiment 5: an encryption was performed for NTSA and TEA algorithms using keys with varying key sizes 48, 64 and 128 bits. Then one bit was changed on the plaintext and the experiment is repeated. It was observed that for every 64-bit block, one-bit change in plaintext resulted in significant changes on the cipher text. Drastic changes were observed for the NTSA algorithm when compared to TEA. Experiment 6: an encryption was performed for NTSA and TEA algorithms using keys with varying key sizes 48, 64 and 128 bits. Then one bit was changed on the plaintext and the experiment is repeated. It was observed that for every 64-bit block, one-bit change in plaintext resulted in significant changes on the cipher text. Drastic changes were observed for the NTSA algorithm when compared to TEA. Experiment 7: an encryption was performed for NTSA and TEA algorithms using keys with varying key sizes 48, 64 and 128 bits. Then one bit was changed on the plaintext and the experiment is repeated. It was observed that for every 64-bit block, one-bit change in plaintext resulted in significant changes on the cipher text. Drastic changes were observed for the NTSA algorithm when compared to TEA. Experiment 8: an encryption was performed for NTSA and TEA algorithms using keys with varying key sizes 48, 64 and 128 bits. Then one bit was changed on the plaintext and the experiment is repeated. It was observed that for every 64-bit block, one-bit change in plaintext resulted in significant changes on the cipher text. Drastic changes were observed for the NTSA algorithm when compared to TEA.