docs: private PublicKey getRSAPublicKey(Provider provider) {
  
          try {
              RSAPublicKeySpec publicKeySpec = getRSAPublicKeySpec();
              KeyFactory factory = provider != null ? KeyFactory.getInstance("RSA", provider)
                      : KeyFactory.getInstance("RSA");
  
              return factory.generatePublic(publicKeySpec);
          } catch (GeneralSecurityException e) {
              throw new IllegalStateException(e);
          }
      }