code: protected PGPPrivateKey findPrivateKey(InputStream secretKey, String password, KeyFilter<PGPSecretKey> keyFilter) throws IOException, PGPException {
      LOGGER.trace("findPrivateKey(InputStream, String, KeyFilter<PGPSecretKey>)");
      LOGGER.trace("Secret Key: {}, Password: {}, KeyFilter: {}", secretKey == null ? "not set" : "set", password == null ? "not set" : "********", keyFilter == null ? "not set" : "set");
      return findPrivateKey(findSecretKey(secretKey, keyFilter), password);
    }
docs: read a private key and unlock it with the given password
  
  @param secretKey
  the secret key stream
  @param password
  the password to use to unlock the private key
  @param keyFilter
  the filter ot find the appropriate key
  @return the appropriate private key  or null if none matches the filter
  @throws IOException
  @throws PGPException