Binary File storing readable text

The following code is used to store password/key in a binary file "rs1.dat" whose sole purpose is that it shouldn't be directly readable from "rs1.dat" but, still the password is stored as a plain text in "rs1.dat" and hence is directly readable from there. pls help me to resolve it.

void changeKey(authenticate m) {

rs1.open("rs1.dat",ios::in|ios::out|ios::ate|ios::binary);
if(rs1.is_open()) {

    cout<<"\n\tEnter New Password\n";
    string s = m.getPass();
    cout<<"\n\tConfirm New Password\n";
    if(m.getPass()!=s) {
        cout<<"\n\t!!Password Doesn't match!!Pls ReEnter\n";
        system("pause");
        changeKey(m);
    }
    rs1.seekp(0,ios::beg);
    rs1.write(s.c_str(),s.size());
    cout<<"\n\tPassword changed successfully\n"; 
    rs1.close();
}else {
    cout<<"Error opening rs1.dat file!!\n";
    exit(0);
}

}

ss of "rs1.dat" file