Question

I am trying to make a very simple Caesar cipher algorithm to encrypt and decrypt the player’s data in my game , but i am getting some weird results.The task of the algorithm is simple, just push foward or backwards the characters in the ascii table.

std::string Encrypt(std::string in,int key)
{
    const char* chars=in.data();
    char* newchar=(char*)malloc(sizeof(char)*in.length());
    for(int c=0;c<in.length();c++)
    {
        newchar[c]=char(((int)chars[c])+key);//I suspect somewhere here is the problem
    }

    std::string out(newchar);
    return out;
}

LOGI("encrypt:%s",Encrypt("hello",10).data());
LOGI("decrypt:%s",Encrypt(Encrypt("hello",10),-10).data());

Output:

encrypt:rovvyu@ 
decrypt:hellok

I dont know much about encryption and i know less about how ascii and the whole character thing works in c

Answer 1

std::string Encrypt(const std::string & in, int key)
{
    std::string out(in);
    for(int i=0; i < in.length(); ++i)
    {
        out[i] += key;
    }
    return out;
}