什麼是 維吉尼亞密碼？
免費線上維吉尼亞密碼工具。使用維吉尼亞密碼表加密或解密文字。
為什麼要使用 維吉尼亞密碼？
- Keyword-based polyalphabetic encryption and decryption
- Autokey mode for stronger encryption
- Character-by-character key visualization
- Index of Coincidence (IC) statistical analysis
- Random secure key generator using crypto.getRandomValues
- Key space up to 26^n for an n-letter keyword
如何使用 維吉尼亞密碼 — 逐步教學
1
Enter your keyword (letters only, case-insensitive).
2
Type your plaintext or ciphertext.
3
Choose Encrypt or Decrypt mode.
4
Toggle Autokey mode to use plaintext as key extension.
5
Enable Key Visualization to see per-character key mapping.
6
Check the IC value to analyze the output statistically.
維吉尼亞密碼適合誰？
- 學習密碼學的學生
- CTF 玩家
- 謎題解謎者
- 密碼學愛好者
維吉尼亞密碼 — 常見問題
Vigenère 相較於 Caesar 的優勢是什麼？
Vigenère uses a keyword to apply different shifts to each letter, making it a polyalphabetic cipher. This resists simple frequency analysis because the same plaintext letter can encrypt to different ciphertext letters depending on position.
什麼是自動金鑰模式？
Autokey mode uses the plaintext itself to extend the keyword. After the keyword is exhausted, the plaintext characters are used as the key for subsequent positions. This prevents the repeating pattern that makes standard Vigenère vulnerable to Kasiski examination.
如何解讀重合指數？
IC measures how likely two randomly selected letters are identical. For English text, IC ≈ 0.0667. For random text, IC ≈ 0.0385. A Vigenère-encrypted text with a short keyword will have IC closer to 0.0385, while a value above 0.045 suggests the text may be monoalphabetic or the keyword is very long.
準備好使用 維吉尼亞密碼 了嗎？
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