anyclass.java

private static boolean initCipherMode(int mode) {
   try {
       sKeyStore.load(null);
       switch (mode) {
           case Cipher.ENCRYPT_MODE:
               PublicKey key = sKeyStore.getCertificate(KEY_ALIAS).getPublicKey();
               PublicKey unrestricted = KeyFactory.getInstance(key.getAlgorithm()).generatePublic(new X509EncodedKeySpec(key.getEncoded()));
               OAEPParameterSpec spec = new OAEPParameterSpec("SHA-256", "MGF1", MGF1ParameterSpec.SHA1, PSource.PSpecified.DEFAULT);
               sCipher.init(mode, unrestricted, spec);
               break;

           case Cipher.DECRYPT_MODE:
               PrivateKey privateKey = (PrivateKey) sKeyStore.getKey(KEY_ALIAS, null);
               sCipher.init(mode, privateKey);
               break;
           default:
               return false;
       }
       return true;
   } catch (KeyStoreException | CertificateException | UnrecoverableKeyException | IOException | NoSuchAlgorithmException | InvalidKeyException | InvalidAlgorithmParameterException | InvalidKeySpecException e) {
       e.printStackTrace();
   }
   return false;
}