added lab2 questions

IS/Lab/Lab2/des_vs_aes256.py

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+from Crypto.Cipher import DES, AES
+from Crypto.Util.Padding import pad, unpad
+import time
+from bokeh.plotting import figure, show
+from bokeh.models import ColumnDataSource
+from bokeh.io import output_file
+
+
+def benchmark_encryption_decryption(cipher_func, data, key):
+    # Measure encryption time
+    start_time = time.time()
+    encrypted = cipher_func(data, key)
+    encrypt_time = time.time() - start_time
+
+    # Measure decryption time
+    start_time = time.time()
+    decrypted = cipher_func(encrypted, key, decrypt=True)
+    decrypt_time = time.time() - start_time
+
+    return encrypt_time, decrypt_time
+
+
+def des_cipher(data, key, decrypt=False):
+    cipher = DES.new(key.encode('utf-8'), DES.MODE_ECB)
+    if decrypt:
+        return unpad(cipher.decrypt(data), DES.block_size).decode('utf-8')
+    else:
+        padded_data = pad(data.encode('utf-8'), DES.block_size)
+        return cipher.encrypt(padded_data)
+
+
+def aes_cipher(data, key, decrypt=False):
+    cipher = AES.new(key.encode('utf-8'), AES.MODE_ECB)
+    if decrypt:
+        return unpad(cipher.decrypt(data), AES.block_size).decode('utf-8')
+    else:
+        padded_data = pad(data.encode('utf-8'), AES.block_size)
+        return cipher.encrypt(padded_data)
+
+
+def main():
+    message = "Performance Testing of Encryption Algorithms"
+
+    # Test with different key sizes
+    des_key = "12345678"  # 8 bytes for DES
+    aes_key = "12345678901234567890123456789012"  # 32 bytes for AES-256
+
+    # Benchmark DES
+    des_encrypt_time, des_decrypt_time = benchmark_encryption_decryption(des_cipher, message, des_key)
+
+    # Benchmark AES-256
+    aes_encrypt_time, aes_decrypt_time = benchmark_encryption_decryption(aes_cipher, message, aes_key)
+
+    # Print results
+    print("Performance Results:")
+    print("-" * 40)
+    print(f"DES Encryption: {des_encrypt_time:.9f} seconds")
+    print(f"DES Decryption: {des_decrypt_time:.9f} seconds")
+    print(f"AES-256 Encryption: {aes_encrypt_time:.9f} seconds")
+    print(f"AES-256 Decryption: {aes_decrypt_time:.9f} seconds")
+
+    # Create Bokeh visualization
+    algorithms = ['DES', 'AES-256']
+    encrypt_times = [des_encrypt_time, aes_encrypt_time]
+    decrypt_times = [des_decrypt_time, aes_decrypt_time]
+
+    # Create the plot
+    p = figure(x_range=algorithms, height=400, title="Encryption/Decryption Performance Comparison",
+               toolbar_location=None, responsive=True)
+
+    p.vbar(x='algorithm', top='encrypt_time', width=0.4, color='blue', alpha=0.7, legend_label="Encryption",
+           source=ColumnDataSource(data=dict(algorithm=algorithms, encrypt_time=encrypt_times)))
+    p.vbar(x='algorithm', top='decrypt_time', width=0.4, color='red', alpha=0.7, legend_label="Decryption",
+           source=ColumnDataSource(data=dict(algorithm=algorithms, decrypt_time=decrypt_times)))
+
+    p.legend.location = "top_right"
+    p.xaxis.axis_label = "Algorithm"
+    p.yaxis.axis_label = "Time (seconds)"
+    p.title.text_font_size = "14px"
+
+    # Save and show the plot
+    output_file("encryption_performance.html")
+    show(p)
+
+
+if __name__ == '__main__':
+    main()