Dart Requires Chilkat v11.5.0+

Sign PDF using ARSS (Aruba Remote Signing Service)

See more Signing in the Cloud Examples

Demonstrates how to digitally sign a PDF using the Aruba Remote Signing Service (ARSS). The example loads a local PDF and certificate, configures the ARSS cloud signer credentials, specifies the OTP authentication type with typeOtpAuth, and creates an LTV-enabled signed PDF where the private key remains protected on the Aruba signing server.

Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // This example requires the Chilkat API to have been previously unlocked.
  // See Global Unlock Sample for sample code.

  final pdf = CkPdf();

  // Load the PDF that will be digitally signed.
  try {
    pdf.loadFile('qa_data/pdf/hello.pdf');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Signing options are specified in a JSON object.
  final json = CkJsonObject();

  // Enable LTV (Long-Term Validation).
  // When ltvOcsp is true, OCSP validation information is embedded in the PDF
  // so that signature validation can continue to succeed in the future,
  // even if the original OCSP responder is no longer available.
  json.updateBool('ltvOcsp', true);

  // Specify the visual appearance of the signature on the PDF page.
  json.updateInt('page', 1);
  json.updateString('appearance.y', 'top');
  json.updateString('appearance.x', 'left');
  json.updateString('appearance.fontScale', '10.0');

  // Text lines displayed in the visible signature appearance.
  // Special values such as "cert_cn" and "current_dt" are replaced
  // with the certificate common name and current date/time.
  json.updateString('appearance.text[0]', 'Digitally signed by: cert_cn');
  json.updateString('appearance.text[1]', 'current_dt');
  json.updateString('appearance.text[2]', 'This is an LTV-enabled signature.');

  // Load the signing certificate.
  // 
  // The private key is NOT stored locally.  Instead, the private key is
  // stored and protected on the Aruba Remote Signing Service (ARSS).
  // 
  // Even though the signing operation will occur remotely, Chilkat still
  // needs the corresponding public certificate locally so that it can
  // construct the CMS/PAdES signature and embed the certificate chain
  // in the signed PDF.
  final cert = CkCert();
  try {
    cert.loadFromFile('qa_data/certs/myCert.cer');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Configure Aruba Remote Signing Service (ARSS) credentials.
  // 
  // When SetCloudSigner is called, Chilkat is instructed to perform
  // cryptographic signing operations through the ARSS web service.
  // The PDF is assembled locally, but the actual RSA signature operation
  // is performed remotely using the private key held by Aruba.
  final jsonArss = CkJsonObject();

  // Required.  Indicates that the cloud signing provider is ARSS.
  jsonArss.updateString('service', 'ARSS');

  // The ARSS certificate identifier (for example, "AS0").
  // This identifies which remote certificate/private key pair should be used.
  // The remote certificate should correspond to the certificate loaded above.
  jsonArss.updateString('certID', 'YOUR_ARSS_CERT_ID');

  // OTP password associated with the Aruba remote-signing account.
  // Depending on the ARSS configuration, an OTP may be required to
  // authorize each signing operation.
  jsonArss.updateString('otpPwd', 'YOUR_OTP_PWD');

  // Specifies the OTP authentication environment.
  // 
  // Common values are:
  //   "demoprod" - Demo/Test environment
  //   "prod"     - Production environment
  // 
  // This value is sent to the ARSS service and determines how the OTP
  // authentication is validated.  The correct value depends on the type
  // of Aruba account and environment that has been provisioned.
  // 
  // If signing fails with an authentication-related error, verify that
  // the typeOtpAuth value matches the environment associated with the
  // ARSS account credentials being used.
  jsonArss.updateString('typeOtpAuth', 'demoprod');

  // ARSS account username.
  jsonArss.updateString('user', 'YOUR_ARSS_USERNAME');

  // ARSS account password.
  jsonArss.updateString('userPWD', 'YOUR_ARSS_PASSWORD');

  // Beginning with Chilkat v11.5.0, the ARSS endpoint can be explicitly
  // specified.  This allows the application to target a particular
  // Aruba signing service endpoint when required.
  jsonArss.updateString('endpoint', 'https://app1.firma-remota.it/ArubaSignerService/webresources/signerservice');

  try {
    cert.setCloudSigner(jsonArss);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Associate the certificate with the PDF object.
  // All subsequent signing operations will use this certificate.
  try {
    pdf.setSigningCert(cert);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Create the signed PDF.
  // 
  // Chilkat performs all PDF processing locally.  When the time comes
  // to generate the cryptographic signature value, Chilkat sends the
  // hash to ARSS, which signs it using the remote private key and returns
  // the signature.  The private key never leaves the Aruba service.
  try {
    pdf.signPdf(json, 'qa_output/hello_ltv_signed.pdf');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('The PDF has been successfully cryptographically signed with long-term validation.');
}