Vigenere Cipher: Encryption, Decryption, and Testing - كتاب الأمن السيبراني - الصف 12 - الفصل 1 - المملكة العربية السعودية

plaintext_int = [ord(i) for i in plaintext] ciphertext = "" # Loop over each character in the plaintext for i in range(len(plaintext_int)): # Calculate the new character by adding the ASCII value of the plaintext # character and the corresponding keyword character (modulo 26) value = (plaintext_int[i] + keyword_as_int[i % keyword_length]) % 26 # Convert the new character back to a string and append it to the ciphertext # Adding 65 converts the value to its ASCII representation as an uppercase letter ciphertext += chr(value + 65) return ciphertext --- SECTION: فك تشفير الرسالة (Decrypting the Message) --- فك تشفير الرسالة (Decrypting the Message) def vigenere_decrypt(ciphertext, keyword): # Calculate the length of the keyword keyword_length = len(keyword) # Convert each character in the keyword to its ASCII value keyword_as_int = [ord(i) for i in keyword] # Convert each character in the ciphertext to its ASCII value ciphertext_int = [ord(i) for i in ciphertext] plaintext = "" # Loop over each character in the ciphertext for i in range(len(ciphertext_int)): # Calculate the original character by subtracting the ASCII value of the # corresponding keyword character from the ciphertext character (modulo 26) value = (ciphertext_int[i] - keyword_as_int[i % keyword_length]) % 26 # Convert the original character back to a string and append it to the plaintext # Adding 65 converts the decrypted value back to its ASCII representation as an uppercase letter plaintext += chr(value + 65) return plaintext --- SECTION: اختبار التشفير (Testing the Cipher) --- اختبار التشفير (Testing the Cipher) encrypted_message = vigenere_encrypt("THERE ARE TWENTY THREE ITEMS IN THE INVENTORY", "LEMON") print(encrypted_message) decrypted_message = vigenere_decrypt(encrypted_message, "LEMON") print(decrypted_message) ELQFREEDSGEAQBGJXFVEPIFWGPQEHVYXFVREMZJRYXAFL THERETARETTWENTYTHREEITEMSTINTTHETINVENTORY وزارة التعليم Ministry of Education 2023 - 1447 122 --- VISUAL CONTEXT --- **IMAGE**: Ministry of Education Logo Description: A logo consisting of a stylized green abstract design resembling a plant or a cluster of dots, accompanied by the text 'وزارة التعليم' in Arabic and 'Ministry of Education 2023 - 1447' in English. Context: Identifies the publisher or educational authority of the textbook.