+ KeyPair keyPair = null;
+ File f = new File("testKeypair");
+ if (f.exists()) {
+ try (ObjectInputStream ois = new ObjectInputStream(new FileInputStream(f))) {
+ keyPair = (KeyPair) ois.readObject();
+ } catch (ClassNotFoundException e) {
+ e.printStackTrace();
+ } catch (IOException e) {
+ e.printStackTrace();
+ }
+ } else {
+ keyPair = kpg.generateKeyPair();
+ try (ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(f))) {
+ oos.writeObject(keyPair);
+ oos.close();
+ } catch (IOException e) {
+ e.printStackTrace();
+ }
+ }
+ return keyPair;