code: public boolean isPassphraseProtected() {
  		try {
  			Reader r = new StringReader(new String(formattedkey, "US-ASCII"));
  			PEMReader pem = new PEMReader(r);
  
  			return pem.getHeader().containsKey("DEK-Info");
  		} catch (IOException e) {
  			return true;
  		}
  	}
docs: /*
  (non-Javadoc)
  
  @see com.sshtools.publickey.SshPrivateKeyFile#isPassphraseProtected()