I decided to try my hand at making an encryption utility, which I lovingly call "FileScrambler". FileScrambler allows the user to encrypt a file (a master-password list, personal diary, or whatever) using a password, and save the resulting jumbled mess to their computer (same folder as the executable is located). They can then decrypt the file using the same password, revealing all their hidden secrets.
Any and all comments are welcome, especially in regards to optimization and standards compliance.
Being a novice programmer, please be gentle with the criticism. This is only my second completed project.
#include <iostream>
#include <string>
#include <fstream>
#include <ctime>
#include <sstream>
#include <cstdlib>
std::string load(std::string nameOfFile){ //done
std::ifstream input;
input.open(nameOfFile.c_str());
std::string content((std::istreambuf_iterator<char>(input)), std::istreambuf_iterator<char>());
return content;
}
std::string encrypt(std::string content, std::string password){ //also decrypts! :D
std::string out;
int p = 0;
for (int index = 0; index < content.size(); ++index){
out += content[index] xor password[p] * p % 30;
++p;
if (p >= password.size())
p = 0;
}
return out;
}
void save(std::string nameOfFile, std::string content){ //saves a file with content Content
char response;
std::ifstream in(nameOfFile.c_str());
std::ofstream of;
if (!in){ //prevents a file from being overwritten unless the user says it's okay (in the nested IF statement).
in.close();
of.open(nameOfFile.c_str());
of << content;
} else{
in.close();
std::cout << "A file with that name already exists. Overwrite? (y/n)\n";
std::cin >> response;
if(response == 'y'){
of.open(nameOfFile.c_str());
of << content;
} else {
std::cout << "Save cancelled. \n";
}
}
of.close();
}
int main(){
int answer = 0;
std::string response, data, nameOfFile, password, encrypted;
char responseC;
do{
switch(answer){
case 0:
{
std::cout << "Available commands:\n";
std::cout << "'0'. list commands\n---\n";
std::cout << "'1'. load a file\n---\n";
std::cout << "'2'. save a file\n---\n";
std::cout << "'3'. encrypt a file\n---\n";
std::cout << "'4'. decrypt a file\n---\n";
std::cout << "'5'. display contents in memory\n---\n";
std::cout << "'6'. close the program\n---\n";
std::cout << "Note: You must load a file before saving, encrypting, or decrypting.\n";
break;
}
case 1: //Load a file's content into memory, stored in the 'data' variable.
{
std::cout << "enter name of file (with extension) to load:\n";
std::cin >> nameOfFile;
data = load(nameOfFile.c_str());
std::cout << "Display contents? (y/n):\n";
std::cin >> responseC;
if (responseC == 'y')
std::cout << data << "\n";
break;
}
case 2: //Save a file's content.
{
std::cout << "save file as: ";
std::cin >> response;
save(response, data);
break;
}
case 3: //Encrypt the content of 'data' by XORing it against a password.
{
std::cout << "Encrypt " << nameOfFile << "?(y/n)\n";
std::cin >> responseC;
if (responseC == 'y'){
//responseC = '\n';
std::cout << "Enter password to decrypt " << nameOfFile << ':' << "\n";
std::cin >> password;
std::cout << "Encrypting... \n";
data = encrypt(data, password);
}
break;
}
case 4: //Decrypt the content of 'data' by XORing it against a password. If the password is correct,
{ //the data actually makes sense. If it isn't, the contents will appear to be gibberish.
std::cout << "Enter password for file: ";
std::cin >> password;
std::cout << "Decrypting...\n";
data = encrypt(data, password); //uses the same same process as encryption.
std::cout << "Done.\n";
break;
}
case 5: //Display the contents of the Data variable.
std::cout << "File contents\n-----\n" << data << "\n-----\n";
break;
case 6:
{
exit(0);
}
default:
std::cout << "Unrecognized command. Enter '0' to view command list\n";
}
std::cout << "Enter command:\n";
std::cin >> answer;
}while(answer != 6);
return 0;
}
Notes:
- This code is a revision of my previous post.
- I know that this encryption method is (very) weak. I chose to use it because it's the only one I know.
- The code is also available on GitHub.
