检查符号和 upper/lower-case 以使用凯撒密码进行加密？

Question

我尝试了几个小时来制作一个简单的 ceasar 密码加密程序。它终于奏效了。但它只能加密没有空格和符号的文本。我不知道如何将这些东西的检查部分实现到代码中。对使代码更清洁和 DRY 的批评者表示赞赏。谢谢

我尝试实现功能的代码：

#Taking Input String + converting to list
message = input("Enter the message for encrypting: ")
message_list = list(message)

#Taking Input Cipher
cipher = int(input("Enter shifting value (1-26): "))

#Alphabet
alphabet = ["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"]

#Defining variable
encrypted_message = []

#Shifting
for letter in message_list:
    if letter not in alphabet:
        encrypted_message.append(letter)
    else:
        #Getting Index of the letter in alphabet
        letter_position = alphabet.index(letter)
        #Getting the shifting value for the letter
        shifting_value = letter_position + cipher
        #Getting the shifted letter
        shifted_letter = alphabet[shifting_value]
        #Adding the corresponding letter to the encrypted message
        encrypted_message.append(shifted_letter)

#Output
print("Original Message: " + message)
print("Encrypted Message: " + str(encrypted_message))
print("Cipher: " + str(cipher))

它应该做什么： 用空格和符号加密消息（凯撒密码），

它在做什么： 发生异常：IndexError 列表索引超出范围

Answer 1

IndexError list index out of range 错误是因为您忘记了模数。没有模数，

shifting_value = letter_position + cipher

此行的值将高于您正在编制索引的数组。记住，凯撒密码是

c = p + 3 mod 26

所以该行必须是

shifting_value = (letter_position + 密码) % 26

注意 1：密码在这里不是一个好的变量名。应该是shiftAmount.
注2：如果要将列表合并成字符串，使用

str1 = ''.join(encrypted_message)

Answer 2

考虑到给出的评论，这是一个可以说更简洁的方法。

#Taking Input String + converting to list
message = input("Enter the message for encrypting: ")
message_list = list(message)

#Taking Input Cipher
cipher = int(input("Enter shifting value (1-26): "))

#Defining variable
encrypted_message = ''

#Shifting
for letter in message_list:
    code_point = ord(letter)
    if code_point > ord('z') or code_point < ord('a') :
        encrypted_message += letter
    else:
        #Getting Index of the letter in alphabet
        letter_position = code_point - ord('a')
        #Getting the shifting value for the letter
        shifting_value = (letter_position + cipher) % 26
        #Getting the shifted letter
        shifted_letter = chr(ord('a') + shifting_value)
        #Adding the corresponding letter to the encrypted message
        encrypted_message += shifted_letter

#Output
print("Original Message: " + message)
print("Encrypted Message: " + str(encrypted_message))
print("Cipher: " + str(cipher))

当然可以把ord('a') 和ord('z') 换成各自的值这样就不用计算了，但是有利于理解

Python 2.7 用raw_input

替换输入

原来的工作版本：

#Taking Input String + converting to list
message = input("Enter the message for encrypting: ")
message_list = list(message)

#Taking Input Cipher
cipher = int(input("Enter shifting value (1-26): "))

#Alphabet
alphabet = ["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"]

#Defining variable
encrypted_message = ''

#Shifting
for letter in message_list:
    if letter not in alphabet:
        encrypted_message += letter
    else:
        #Getting Index of the letter in alphabet
        letter_position = alphabet.index(letter)
        #Getting the shifting value for the letter
        shifting_value = (letter_position + cipher) % 26
        #Getting the shifted letter
        shifted_letter = alphabet[shifting_value]
        #Adding the corresponding letter to the encrypted message
        encrypted_message += shifted_letter

#Output
print("Original Message: " + message)
print("Encrypted Message: " + str(encrypted_message))
print("Cipher: " + str(cipher))

检查符号和 upper/lower-case 以使用凯撒密码进行加密？

Checking for symbols and upper/lower-case for encrypting with ceasar cipher?

python

encryption

python-3.x

caesar-cipher