خوارزمية تشفير فيجنر - كتاب الأمن السيبراني - الصف 12 - الفصل 1 - المملكة العربية السعودية

خوارزمية تشفير فيجنر Vigenère Cipher Algorithm يُعد هذا التشفير امتدادًا لخوارزمية تشفير قيصر، حيث يتم إزاحة كل حرف بناءً على كلمة مفتاحية لتشفير الرسائل، وهي مثل خوارزمية تشفير قيصر ولكنها أكثر تعقيدًا منها، ورغم ذلك لا يُعد هذا التعقيد كافيًا للاستخدام في أنظمة الإنتاج. --- SECTION: شكل 3.8: تمثيل خوارزمية تشفير فيجنر --- شكل 3.8: تمثيل خوارزمية تشفير فيجنر --- SECTION: مثال: --- مثال: افترض أن النص غير المشفر (الرسالة الأصلية) هو "HELLO"، وسيتم استخدام الكلمة الأساسية "KEY". أولاً، ستقوم بمحاذاة الكلمة الأساسية مع النص غير المشفر الخاص بك، وتكرر الكلمة الأساسية حسب الضرورة: نص غير مشفر HELLO ||||| KEYKE الكلمة المفتاحية لذلك، بالنسبة إلى كلمتك الأساسية "KEY"، ستكون الإزاحات K = 10 ، E = 4 ، Y = 24. يؤدي تطبيق هذه الإزاحات على كل حرف في "HELLO" إلى تحقيق ما يلي: "H" (تم إزاحتها بمقدار 10 مواضع) لتصبح "R". "E" (تم إزاحتها بمقدار 4 مواضع) لتصبح "I". وزارة التعليم Ministry of Education 2025 - 1447 120 --- VISUAL CONTEXT --- **TABLE**: تمثيل خوارزمية تشفير فيجنر Description: A 26x26 grid, known as the Vigenère square or tabula recta, used for encryption. The top row (A-Z) represents the key characters, and the leftmost column (A-Z) represents the plaintext characters. Each subsequent row is a Caesar cipher shifted version of the previous row. The intersection of a key column and a plaintext row gives the ciphertext character. The diagram includes labels pointing to 'المفتاح' (Key), 'الحرف المشفر' (Ciphertext character), and 'الحرف غير المشفر' (Plaintext character). Table Structure: Headers: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z Rows: Row 1: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z Row 2: B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | A Row 3: C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | A | B Row 4: D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | A | B | C Row 5: E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | A | B | C | D Row 6: F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | A | B | C | D | E Row 7: G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | A | B | C | D | E | F Row 8: H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | A | B | C | D | E | F | G Row 9: I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | A | B | C | D | E | F | G | H Row 10: J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | A | B | C | D | E | F | G | H | I Row 11: K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | A | B | C | D | E | F | G | H | I | J Row 12: L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | A | B | C | D | E | F | G | H | I | J | K Row 13: M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | A | B | C | D | E | F | G | H | I | J | K | L Row 14: N | O | P | Q | R | S | T | U | V | W | X | Y | Z | A | B | C | D | E | F | G | H | I | J | K | L | M Row 15: O | P | Q | R | S | T | U | V | W | X | Y | Z | A | B | C | D | E | F | G | H | I | J | K | L | M | N Row 16: P | Q | R | S | T | U | V | W | X | Y | Z | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O Row 17: Q | R | S | T | U | V | W | X | Y | Z | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P Row 18: R | S | T | U | V | W | X | Y | Z | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q Row 19: S | T | U | V | W | X | Y | Z | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R Row 20: T | U | V | W | X | Y | Z | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S Row 21: U | V | W | X | Y | Z | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T Row 22: V | W | X | Y | Z | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U Row 23: W | X | Y | Z | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V Row 24: X | Y | Z | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W Row 25: Y | Z | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X Row 26: Z | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y Calculation needed: The table is a reference for Vigenère cipher encryption, where the intersection of a plaintext row and a key column yields the ciphertext character. X-axis: المفتاح (Key) Y-axis: الحرف غير المشفر (Plaintext character) Context: This table is the fundamental tool for understanding and performing the Vigenère cipher, showing all possible shifts for each letter combination. **DIAGRAM**: محاذاة الكلمة الأساسية مع النص غير المشفر Description: A textual diagram illustrating the alignment of the plaintext 'HELLO' with the repeated key 'KEYKE'. Vertical lines indicate the one-to-one correspondence between each plaintext character and its respective key character for the encryption process. Key Values: نص غير مشفر, HELLO, KEYKE, الكلمة المفتاحية Context: This diagram visually represents the initial step of the Vigenère cipher, which involves repeating the key to match the length of the plaintext and aligning them for character-by-character encryption. **TABLE**: تشفير الحرف H باستخدام المفتاح K Description: A partial Vigenère cipher table demonstrating the encryption of the plaintext character 'H' using the key character 'K'. The row corresponding to 'H' and the column corresponding to 'K' are highlighted, showing their intersection at the ciphertext character 'R'. Table Structure: Headers: A | B | C | D | E | F | G | H | I | J | K Rows: Row 1: A | B | C | D | E | F | G | H | I | J | K Row 2: B | C | D | E | F | G | H | I | J | K | L Row 3: C | D | E | F | G | H | I | J | K | L | M Row 4: D | E | F | G | H | I | J | K | L | M | N Row 5: E | F | G | H | I | J | K | L | M | N | O Row 6: F | G | H | I | J | K | L | M | N | O | P Row 7: G | H | I | J | K | L | M | N | O | P | Q Row 8: H | I | J | K | L | M | N | O | P | Q | R Calculation needed: This table visually demonstrates the encryption of a single character 'H' using 'K' as the key, resulting in 'R'. Context: This visual aids in understanding the specific application of the Vigenère square for encrypting the first character of the example plaintext 'HELLO'. **TABLE**: تشفير الحرف E باستخدام المفتاح E Description: A partial Vigenère cipher table demonstrating the encryption of the plaintext character 'E' using the key character 'E'. The row corresponding to 'E' and the column corresponding to 'E' are highlighted, showing their intersection at the ciphertext character 'I'. Table Structure: Headers: A | B | C | D | E Rows: Row 1: A | B | C | D | E Row 2: B | C | D | E | F Row 3: C | D | E | F | G Row 4: D | E | F | G | H Row 5: E | F | G | H | I Calculation needed: This table visually demonstrates the encryption of a single character 'E' using 'E' as the key, resulting in 'I'. Context: This visual aids in understanding the specific application of the Vigenère square for encrypting the second character of the example plaintext 'HELLO'.