栅栏密码(Fence crypto)

栅栏密码(Fence crypto)

• 加密对象: 所有字符

• 原理:

  • 该密码是一种移位密码，将明文的顺序按照某种规则打乱

  • 该密码需要一个秘钥，即在加密过程中需要使用到的列数，将明文按顺序排成列,例如：列数为4，明文为: “i will beat you this day”,

    i		w	i
    l	l		b
    e	a	t
    y	o	u
    t	h	i	s
    	d	a	y

  • 然后按照列顺序组成明文，如表密文为: ileyt  laohdw tuiaib  sy

• 代码:

  # write by 2021/8/5
  # 栅栏密码def encrypt_fence(string, key):ciphertext = ""temp = []for i in range(key):temp.append("")for index, i in enumerate(string):temp[index % key] += i# print("".join(temp))ciphertext = "".join(temp)return ciphertextdef decrypt_fence(string, key):plaintext = ""length = len(string)min_row = length // keymax_num = length % keytemp = []index = 0for i in range(key):if i < max_num:temp.append(string[index:index+min_row+1])index += min_row + 1else:temp.append(string[index:index+min_row])index += min_row# print(temp)for i in range(length):plaintext += temp[i % key][i // key]return plaintextif __name__ == '__main__':key_ = 4ciphertext_ = encrypt_fence("i will beat you this day", key_)plaintext_ = decrypt_fence(ciphertext_, key_)print(f"{plaintext_} : {ciphertext_}")