加密和解密密码会引发 ValueError

Question

我正在制作一个程序，该程序应该对您传入的密码进行加密。但是，每当我运行它时，它都会引发错误：

Password = float(input('Enter Password: '))

ValueError: could not convert string to float: 'Banana'（我为这个测试选择的词）

这是我的代码：

#Macchiat0
#10 May 2016
#This program will encrypt and decrypt user passwords.

#init
encryptionlist = (('a','q'),
                  ('b','w'),
                  ('c','e'),
                  ('d','r'),
                  ('e','t'),
                  ('f','y'),
                  ('g','u'),
                  ('h','i'),
                  ('i','o'),
                  ('j','p'),
                  ('k','a'),
                  ('l','s'),
                  ('m','d'),
                  ('n','f'),
                  ('o','g'),
                  ('p','h'),
                  ('q','j'),
                  ('r','k'),
                  ('s','l'),
                  ('t','z'),
                  ('u','x'),
                  ('v','c'),
                  ('w','v'),
                  ('x','b'),
                  ('y','n'),
                  ('z','m'))

print('This program will encrypt and decrypt user passwords')

#Program Menu
ans = True

while True:
    print('1. Enter 1 to encrypt a password: ')
    print('2. Enter 2 to decrypt a password: ')
    print('3. Exit/Quit')
    ans = input('What do you want to do? ')

    if ans == "1":
        print("\n Enter 1 to encrypt a password: ")

        Password = float(input('Enter Password: '))
        print('Your new encryptid password is:', Password)
    if ans == "2":
        print("\n Enter 2 to decrypt a password: ")

        Password = float(input('Enter Password: '))
        print('Your new decrypted password is:', Password)
    elif ans == "3":
        print("\n Goodbye")
        break
    else:
        print("\n Not Valid Choice Try Again")

Answer 1

在 Python 3.x 中，input 将返回一个字符串。您可以在the PyDocs 中了解它。当您给 Python 输入 Banana 时，它会感到困惑。您不能将 Banana 转换为 float 类型。如果您正在考虑将字符串转换为程序的一组索引，您可以试试这个（注意我在您的代码中添加并实现的 3 个新函数）：

encryptionlist = (('a','q'),
                  ('b','w'),
                  ('c','e'),
                  ('d','r'),
                  ('e','t'),
                  ('f','y'),
                  ('g','u'),
                  ('h','i'),
                  ('i','o'),
                  ('j','p'),
                  ('k','a'),
                  ('l','s'),
                  ('m','d'),
                  ('n','f'),
                  ('o','g'),
                  ('p','h'),
                  ('q','j'),
                  ('r','k'),
                  ('s','l'),
                  ('t','z'),
                  ('u','x'),
                  ('v','c'),
                  ('w','v'),
                  ('x','b'),
                  ('y','n'),
                  ('z','m'))

print('This program will encrypt and decrypt user passwords')

def letter_index(letter):
    return ord(letter) - 97

def encrypt(text):
    lowered_text = text.lower()
    encrypted_text = [letter_index(x) for x in lowered_text]
    encrypted_text = "".join([encryptionlist[x][1] for x in encrypted_text])
    return encrypted_text

def decrypt(text):
    lowered_text = text.lower()
    # the decryption process will yield worst case speed of O(n)
    # if you were to loop through the whole thing.
    # A faster way to sort it by the value e.g.
    sorted_encryptionlist = sorted(encryptionlist, key=lambda x: x[1])
    decrypted_text = [letter_index(x) for x in lowered_text]
    decrypted_text = "".join([sorted_encryptionlist[x][0] for x in decrypted_text])
    return decrypted_text


#Program Menu
ans = True

while True:
    # Get user input
    print('1. Enter 1 to encrypt a password: ')
    print('2. Enter 2 to decrypt a password: ')
    print('3. Exit/Quit')
    ans = input('What do you want to do? ')

    if ans == "1":
        print("\nEnter 1 to encrypt a password: ")

        Password = input('Enter Password: ')

        print('Your new encryptid password is:', encrypt(Password))
    if ans == "2":
        print("\nEnter 2 to decrypt a password: ")

        Password = input('Enter Password: ')

        print('Your new decrypted password is:', decrypt(Password))
    elif ans == "3":
        print("\nGoodbye")
        break
    else:
        print("\nNot Valid Choice Try Again")

当然，这是一个弱加密，如果你想要更好的加密（专业人士使用的东西），看看pycrypto。