XOR encryption

Quick and messy XOR encryptor. Reads in a string of any length and outputs a binary string of it xored with the key hardcoded in the source. See the decrypter

#include <iostream>
#include <string>
#include <cmath>
#include <vector>
using namespace std;

vector<int> to_binary(string binarify_me) {
	vector<int> return_me;

	for(int i=0; i<binarify_me.size(); i++) {
		vector<int> temp;
		int char_as_int = (int)binarify_me[i];

		while(char_as_int != 0) {
			if(char_as_int % 2 == 0)
				temp.push_back(0);

			else
				temp.push_back(1);

			char_as_int /= 2;
		}

		while(temp.size() != 8)
			temp.push_back(0);

		for(int i=temp.size()-1; i>=0; --i)
			return_me.push_back(temp[i]);
	}

	return return_me;
}

vector<int> xor_encrypt(vector<int> encrypt_me, vector<int> with_me) {
	vector<int> return_me;

	for(int i=0; i<encrypt_me.size(); i++) {
		int key_index = i;

		while(key_index > with_me.size())
			key_index = key_index-with_me.size();

		int xored = encrypt_me[i] ^ with_me[key_index];
		return_me.push_back(xored);
	}

	return return_me;
}

string from_binary(vector<int> stringify_me) {
	string return_me = "";

	for(int i=7; i<stringify_me.size(); i+=8) {
		int char_as_int = 0;

		for(int j=0; j<8; j++)
			char_as_int += stringify_me[i-j] * pow(2, j);

		return_me += (char)char_as_int;
	}

	return return_me;
}


int main() {
	string encryption_key = "this is the key.";
	vector<int> binary_key = to_binary(encryption_key);

	string encrypt_me;
	getline(cin, encrypt_me);
	vector<int> binary_encrypt_me = to_binary(encrypt_me);

	vector<int> encrypted = xor_encrypt(binary_encrypt_me, binary_key);


	for(int i=0; i<encrypted.size(); i++)
		cout << encrypted[i];

	cout << endl;
	return 0;
}