在Linux Vigenere密码中将随机字符添加到字符串结尾

Question

我正在尝试创建一个Vigenere密码，我有一个问题，在字符串的末尾，它是随机添加一个随机字符，如：^ V或^ U ....这取决于字符串我我正在尝试加密或解密。我在c ++ 11中编写代码，在Linux服务器上运行它。任何输入都会很棒。谢谢！

这是我的代码：

#include "Vigenre.h"


/**
* Sets the key to use
* @param key - the key to use
* @return - True if the key is valid and False otherwise
*/
bool Vigenre::setKey(const string& key)
{
    //Make sure key provided is a string.
    if (isdigit(key[0]))
        return false;
    else
    {
        //Store length of key.
        //Convert string to ascii, subtract 97 to normalize numbers, and store as vectorKey.
        //Ex: "lemon" turns into l=11, e=4, m=12, o=14, n=13
        this->keyLength = key.length();

        for (int i = 0; i < keyLength; i++)
        {
            this->vectorKey.push_back((int)key[i] - 97);
        }
    }
    return true;
}

/**
* Encrypts a plaintext string
* @param plaintext - the plaintext string
* @return - the encrypted ciphertext string
*/
string Vigenre::encrypt(const string& plaintext)
{
    //Must setup vectors into header file.
    setupVectors(plaintext);

    //Add to encrypt values, store as ascii.
    //Also prevent ascii from leaving alphabetical value section.
    for (int i = 0; i < inputLength; i++)
    {
        this->vectorOutput.push_back(vectorInput[i] + vectorKeyLong[i] + 97);

        if (vectorOutput[i] > 122)
            vectorOutput[i] -= 26;
    }
    return readyResult();
}

/**
* Decrypts a string of ciphertext
* @param cipherText - the ciphertext
* @return - the plaintext
*/
string Vigenre::decrypt(const string& cipherText)
{
    //Must setup vectors into header file.
    setupVectors(cipherText);

    //Subtract to decrypt values, store as ascii.
    //Also prevent ascii from leaving alphabetical value section.
    for (int i = 0; i < inputLength; i++)
    {
        this->vectorOutput.push_back(vectorInput[i] - vectorKeyLong[i] + 97);

        if (vectorOutput[i] < 97)
            vectorOutput[i] += 26;
    }
    return readyResult();

}

/**
* Setup the vectors in this header file using parameter
* @param text - the plaintext from encrypt, or ciphertext from decrypt
*/
void Vigenre::setupVectors(const string & text)
{
    //Store length of plaintext.
    //Convert plaintext to ascii, subtract 97 to normalize numbers, and store as vectorInput.
    this->inputLength = text.length();

    for (int i = 0; i < inputLength; i++)
    {
        this->vectorInput.push_back((int)text[i] - 97);
    }

    //Take the key, and duplicate it over and over until each input character has a key character.
    //Ex) input: attackatdawn
    //  longkey: lemonlemonle
    for (int i = 0; i < inputLength; i++)
    {
        this->vectorKeyLong.push_back(vectorKey[i % keyLength]);
    }
}

/**
* Ready the result for output.
*/
string Vigenre::readyResult()
{
    //-REQUIRES- function setupVectors(text) and encrypt() or decrypt() to have been used.
    //Convert ascii numbers back into letters. Store as result.
    string result;
    for (int i = 0; i < inputLength; i++)
    {
        char temp = static_cast<char>(vectorOutput[i]);
        result.push_back(vectorOutput[i]);
    }
    return result;
}