150 lines
3.9 KiB
Python
150 lines
3.9 KiB
Python
import string
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def _process_vigenere_char(char, key_char, mode):
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if not char.isalpha():
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return char
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start = ord('A') if char.isupper() else ord('a')
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shift = ord(key_char) - ord('A')
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if mode == "encrypt":
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processed_char_code = (ord(char) - start + shift) % 26 + start
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elif mode == "decrypt":
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processed_char_code = (ord(char) - start - shift) % 26 + start
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else:
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raise ValueError("无效的模式，必须是 'encrypt' 或 'decrypt'")
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return chr(processed_char_code)
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def vigenere_encrypt(plaintext, key):
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"""
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维吉尼亚加密
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Args:
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plaintext: 明文字符串
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key: 密钥字符串
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Returns:
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加密后的字符串
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"""
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processed_key = ''.join(filter(str.isalpha, key.upper()))
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if not processed_key:
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raise ValueError("密钥不能为空")
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ciphertext_chars = []
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key_length = len(processed_key)
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key_index = 0
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for char in plaintext:
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if char.isalpha():
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encrypted_char = _process_vigenere_char(char, processed_key[key_index % key_length], "encrypt")
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ciphertext_chars.append(encrypted_char)
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key_index += 1
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else:
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ciphertext_chars.append(char)
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return ''.join(ciphertext_chars)
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def vigenere_decrypt(ciphertext, key):
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"""
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维吉尼亚解密
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Args:
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ciphertext: 密文字符串
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key: 密钥字符串
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Returns:
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解密后的字符串
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"""
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processed_key = ''.join(filter(str.isalpha, key.upper()))
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if not processed_key:
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raise ValueError("密钥不能为空")
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plaintext_chars = []
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key_length = len(processed_key)
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key_index = 0
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for char in ciphertext:
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if char.isalpha():
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decrypted_char = _process_vigenere_char(char, processed_key[key_index % key_length], "decrypt")
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plaintext_chars.append(decrypted_char)
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key_index += 1
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else:
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plaintext_chars.append(char)
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return ''.join(plaintext_chars)
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def display_vigenere_table():
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"""
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显示维吉尼亚加密表
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"""
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alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
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print("维吉尼亚加密表:")
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print(" " + ' '.join(alphabet))
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print(" +" + "-" * 51)
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for i, row_start in enumerate(alphabet):
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row = []
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for j in range(26):
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# 计算每个位置的字符
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char = chr((ord(row_start) - ord('A') + j) % 26 + ord('A'))
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row.append(char)
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print(f"{row_start} | {' '.join(row)}")
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print()
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def main():
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"""
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主函数：交互式界面
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"""
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print("=== 维吉尼亚加密工具 ===")
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while True:
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print("\n请选择操作:")
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print("1. 加密")
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print("2. 解密")
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print("3. 显示加密表")
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print("4. 退出")
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choice = input("请输入选择 (1-4): ").strip()
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if choice == '1':
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plaintext = input("请输入明文: ").strip()
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key = input("请输入密钥: ").strip()
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try:
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ciphertext = vigenere_encrypt(plaintext, key)
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print(f"加密结果: {ciphertext}")
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except Exception as e:
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print(f"加密错误: {e}")
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elif choice == '2':
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ciphertext = input("请输入密文: ").strip()
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key = input("请输入密钥: ").strip()
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try:
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plaintext = vigenere_decrypt(ciphertext, key)
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print(f"解密结果: {plaintext}")
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except Exception as e:
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print(f"解密错误: {e}")
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elif choice == '3':
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display_vigenere_table()
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elif choice == '4':
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print("退出程序。")
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break
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else:
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print("无效选择，请重新输入。")
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if __name__ == "__main__":
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main() |