Hi all, I have a small problem with java, i need to convert a strig key
to a privatekey

I generate a RSA keypair and i write my privatekey into a file

try
{
FileWriter out = new FileWriter ("key.txt");
out.write(myprivatekey);
out.close();
}

where myprivatekey is a string
PrivateKey kpriv = kp.getPrivate();
myprivatekey = (kpriv+"");

But now, if i want to retrive the key i have an error in cast

try {
       BufferedReader in = new BufferedReader(new
FileReader("key.txt"));
       String str,bo="";
       while ((str = in.readLine()) != null) {
           bo = bo+"\n"+str;
       }
in.close();

kpriv = (PrivateKey)bo; <-- error (crypto1.java:71: inconvertible
types)

Can anyone help me in this cast ? Thanks a lot