code: @Override
      public LtiVerificationResult verifyParameters(Map<String, String> parameters, String url, String method, String secret) throws LtiVerificationException {
          OAuthMessage oam = new OAuthMessage(method, url, parameters.entrySet());
          OAuthConsumer cons = new OAuthConsumer(null, parameters.get(OAUTH_KEY_PARAMETER), secret, null);
          OAuthValidator oav = new SimpleOAuthValidator();
          OAuthAccessor acc = new OAuthAccessor(cons);
  
          try {
              oav.validateMessage(oam, acc);
          } catch (Exception e) {
              return new LtiVerificationResult(false, LtiError.BAD_REQUEST, "Failed to validate: " + e.getLocalizedMessage() + ", Parameters: " + Arrays.toString(parameters.entrySet().toArray()));
          }
          return new LtiVerificationResult(true, new LtiLaunch(parameters));
      }
docs: This method will verify a collection of parameters
  @param parameters the parameters that will be verified. mapped by key &amp; value
  @param url the url this request was made at
  @param method the method this url was requested with
  @param secret the secret to verify the propertihes with
  @return
  @throws LtiVerificationException