python之有时在加密数据时我的代码返回带有奇怪符号的特定结果

我正在用 python3 学习密码学

现在我正在研究凯撒密码，这是我的问题

我尝试使用 key 16 加密“hdjdyueeeje” 这就是结果 "zwzt??uuzu"

你能解释一下我做错了什么以及如何解决吗

我的代码:

print("\n----------------Caesar_Cipher----------------\n") 
 
print('  1) Crypt mode') 
print("  2) Decrypt mode") 
 
try: 
    mode = int(input('\n  [#]  Enter number what you need (1,2) : ')) 
 
    if mode == 1: 
        print("\n--------Crypting process is starting---------") 
        key = int(input("\n  [#]  Enter here key which will be used to crypt data \n       (number from 1 to 25 including) --> ")) 
 
        if 1 >= key or key > 25: 
            print("   You choosed wrong number. I will make it 1 automatically")   
            key = 1 
        else: 
            pass 
 
        msg = input("\n  [#]  Now enter your message what you wanna crypt \ 
                \n    -->") 
        print("") 
 
        msgc = "" 
        for letter in msg: 
            x = ord(letter) 
            y = chr(x + key) 
            msgc += y 
 
        print('\n Crypted data -->',msgc) 
    elif mode == 2: 
        print("\n-------Decrypting process is starting--------") 
 
        key = int(input("\n  [#]  Enter here key which will be used to decrypt data \n       (number from 1 to 25 including) --> ")) 
 
        if 1 >= key or key > 25: 
            print("   You choosed wrong number. I will make it 1 automatically")   
            key = 1 
        else: 
            pass 
 
        msg = input("\n  [#]  Now enter your message what you wanna decrypt \ 
                \n    -->") 
        print("") 
        msgd = "" 
        for letter in msg: 
            x = ord(letter) 
            y = chr(x - key) 
            msgd += y 
 
        print('\n Decrypted data -->',msgd) 
    else: 
        print("Number not defined") 

就这样

请您参考如下方法:

你的问题在这里:

x = ord(letter) 
y = chr(x + key) # <- problem 
msgc += y 

如果没有足够的字母留下更高的代码，字母表需要环绕。例如，当您尝试加密 y 时，您只能加 1 才能得到 z。如果 key 为 2，则需要环绕并返回到 a。这种“环绕”可以很容易地通过减去字母表的长度来完成。此版本的代码有效:

x = ord(letter) 
y = x + key 
if y > ord('z'): 
    y -= 26 
msgc += chr(y) 

请注意，这仅适用于小写字母。