簡單替換與維吉尼亞密碼技術解析

def hackSimpleSubstitution(ciphertext):
    # 初始化空白對映
    intersectedMap = blankLetterMapping()
    cipherwordList = nonLettersOrSpacePattern.sub('', ciphertext.upper()).split()
    
    for cipherword in cipherwordList:
        newMap = blankLetterMapping()
        wordPattern = getWordPattern(cipherword)
        
        if wordPattern not in wordPatterns.allPatterns:
            continue
        
        # 更新字母對映
        for candidate in wordPatterns.allPatterns[wordPattern]:
            newMap = addLettersToMapping(newMap, cipherword, candidate)
        
        # 交叉驗證對映
        intersectedMap = intersectMappings(intersectedMap, newMap)
    
    return removeSolvedLettersFromMapping(intersectedMap)

def decryptWithCipherletterMapping(ciphertext, letterMapping):
    key = ['x'] * len(LETTERS)
    
    for cipherletter in LETTERS:
        if len(letterMapping[cipherletter]) == 1:
            keyIndex = LETTERS.find(letterMapping[cipherletter][0])
            key[keyIndex] = cipherletter
        else:
            ciphertext = ciphertext.replace(cipherletter.lower(), '_')
            ciphertext = ciphertext.replace(cipherletter.upper(), '_')
    
    key = ''.join(key)
    return simpleSubCipher.decryptMessage(key, ciphertext)

def vigenere_cipher(plaintext, key):
    # 將金鑰轉換為子金鑰列表
    subkeys = [ord(k.upper()) - ord('A') for k in key]
    
    # 初始化密鑰
    ciphertext = ""
    
    # 遍歷明文的每個字元
    for i, char in enumerate(plaintext):
        if char.isalpha():
            # 取得對應的子金鑰
            subkey = subkeys[i % len(subkeys)]
            
            # 進行凱撒密碼加密
            if char.isupper():
                ciphertext += chr((ord(char) - ord('A') + subkey) % 26 + ord('A'))
            else:
                ciphertext += chr((ord(char) - ord('a') + subkey) % 26 + ord('a'))
        else:
            ciphertext += char
    
    return ciphertext

# 範例使用
plaintext = "Common sense is not so common."
key = "PIZZA"
ciphertext = vigenere_cipher(plaintext, key)
print(ciphertext)

# Vigenere Cipher (Polyalphabetic Substitution Cipher)

import pyperclip

LETTERS = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'

def main():
    myMessage = """Alan Mathison Turing was a British mathematician..."""
    myKey = 'ASIMOV'
    myMode = 'encrypt' # 設定為 'encrypt' 或 'decrypt'

    if myMode == 'encrypt':
        translated = encryptMessage(myKey, myMessage)
    elif myMode == 'decrypt':
        translated = decryptMessage(myKey, myMessage)

    print('%sed message:' % (myMode.title()))
    print(translated)
    pyperclip.copy(translated)
    print()
    print('訊息已複製到剪貼簿。')

def encryptMessage(key, message):
    return translateMessage(key, message, 'encrypt')

def decryptMessage(key, message):
    return translateMessage(key, message, 'decrypt')

def translateMessage(key, message, mode):
    translated = [] # 儲存加密/解密後的訊息字串

    keyIndex = 0
    key = key.upper()

    for symbol in message: # 對訊息中的每個字元進行迴圈
        num = LETTERS.find(symbol.upper())
        if num != -1: # -1 表示 symbol.upper() 不在 LETTERS 中
            if mode == 'encrypt':
                num += LETTERS.find(key[keyIndex]) # 如果是加密則加上金鑰
            elif mode == 'decrypt':
                num -= LETTERS.find(key[keyIndex]) # 如果是解密則減去金鑰

            num %= len(LETTERS) # 處理可能的環繞

            # 將加密/解密後的符號新增到 translated 的末尾
            if symbol.isupper():
                translated.append(LETTERS[num])
            elif symbol.islower():
                translated.append(LETTERS[num].lower())

            keyIndex += 1 # 移至金鑰中的下一個字母
            if keyIndex == len(key):
                keyIndex = 0
        else:
            # 如果符號不在 LETTERS 中，則按原樣新增到 translated
            translated.append(symbol)

    return ''.join(translated)

if __name__ == '__main__':
    main()

def translateMessage(key, message, mode):
    translated = []
    keyIndex = 0
    key = key.upper()

    for symbol in message:
        num = LETTERS.find(symbol.upper())
        if num != -1:
            if mode == 'encrypt':
                num += LETTERS.find(key[keyIndex])
            elif mode == 'decrypt':
                num -= LETTERS.find(key[keyIndex])
            num %= len(LETTERS)
            # 取得加密/解密後的字母
            if symbol.isupper():
                translated.append(LETTERS[num])
            else:
                translated.append(LETTERS[num].lower())
            keyIndex = (keyIndex + 1) % len(key)
        else:
            translated.append(symbol)
    return ''.join(translated)