尝试加密/解密时发生vigenere密码错误

Question

我运行程序时收到此错误：

Traceback (most recent call last):
File "C:/Users/####/PycharmProjects/hw5/Homework5_Cepero.py", line 112, in <module>
decrypt()
File "C:/Users/####/PycharmProjects/hw5/Homework5_Cepero.py", line 78, in decrypt
encrypted.append({stringlist[i] - keylist[i]} % 29)
TypeError: list indices must be integers, not str

Process finished with exit code 1

代码如下：

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", ",", ".", "-"]

def encrypt():
    count = 0
    i = 0
    output = []
    encrypted = []
    keylist = []
    stringlist = []
    string = raw_input("Please enter a string to encrypt: ")
    string = string.replace(' ', '')
    key = raw_input("Please enter the key you'd like to use: ")
    keylength = len(key)
    stringlength = len(string)
    overlap = stringlength % keylength
    leftovers = key[:overlap]
    random = stringlength - overlap
    random = stringlength / keylength
    key = (int(random) * key) + leftovers

    #convert Key to uppercase
    for i in key:
        number = Alphabet.index(i.upper())
        keylist.append(number)
    #convert String to uppercase
    for i in string:
        number = Alphabet.index(i.upper())
        stringlist.append(number)

    while count < stringlength:
            encrypted.append((stringlist[i] + keylist[i]) % 29)
            count += 1
            i += 1
    for N in encrypted:
        output.append(Alphabet[N])

    string = ''.join(output)
    print" "
    print"Output:"
    print" "
    print "The encoded text is:", string
    print" "


def decrypt():
    count = 0
    i = 0
    output = []
    encrypted = []
    keylist = []
    stringlist = []
    string = raw_input("Please enter a string to decrypt: ")
    string = string.replace(' ', '')
    key = raw_input("Please enter the key you'd like to use: ")
    keylength = len(key)
    stringlength = len(string)
    overlap = stringlength % keylength
    leftovers = key[:overlap]
    random = stringlength - overlap
    random = stringlength / keylength
    key = (int(random) * key) + leftovers

    #convert Key to uppercase
    for i in key:
        number = Alphabet.index(i.upper())
        keylist.append(number)
    #convert String to uppercase
    for i in string:
        number = Alphabet.index(i.upper())
        stringlist.append(number)

    while count < stringlength:
            encrypted.append({stringlist[i] - keylist[i]} % 29)
            count += 1
            i += 1
    for N in encrypted:
        output.append(Alphabet[N])

    string = ''.join(output)
    print" "
    print"Output:"
    print" "
    print "The decoded text is:", string
    print" "

# main function
if __name__ == '__main__':

    selection = ''

    while selection != 3:
            selection = raw_input("\n\nEnter 1 to encrypt, 2 to decrypt, or 3 to exit: ")

            if selection == '1':
                    encrypt()
            elif selection == '2':
                    decrypt()
            elif selection == '3':
                    print "Thanks for using my program"
                    exit()

Answer 1

在这个声明中

encrypted.append((stringlist[i] + keylist[i]) % 29)

你正在使用i，它以前用于对字符串进行迭代。

for i in string:

所以，i仍然有字符串的最后一个字符。您正在使用该字符串索引列表。这就是为什么python会抛出这个错误。