(Objective-C) 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.

Note: This example requires Chilkat v11.5.0 or greater.

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#import <CkoPdf.h>
#import <CkoJsonObject.h>
#import <CkoCert.h>

BOOL success = NO;

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

CkoPdf *pdf = [[CkoPdf alloc] init];

// Load the PDF that will be digitally signed.
success = [pdf LoadFile: @"qa_data/pdf/hello.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf.LastErrorText);
    return;
}

// Signing options are specified in a JSON object.
CkoJsonObject *json = [[CkoJsonObject alloc] init];

// 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" value: YES];

// Specify the visual appearance of the signature on the PDF page.
[json UpdateInt: @"page" value: [NSNumber numberWithInt: 1]];
[json UpdateString: @"appearance.y" value: @"top"];
[json UpdateString: @"appearance.x" value: @"left"];
[json UpdateString: @"appearance.fontScale" value: @"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]" value: @"Digitally signed by: cert_cn"];
[json UpdateString: @"appearance.text[1]" value: @"current_dt"];
[json UpdateString: @"appearance.text[2]" value: @"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.
CkoCert *cert = [[CkoCert alloc] init];
success = [cert LoadFromFile: @"qa_data/certs/myCert.cer"];
if (success == NO) {
    NSLog(@"%@",cert.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.
CkoJsonObject *jsonArss = [[CkoJsonObject alloc] init];

// Required.  Indicates that the cloud signing provider is ARSS.
[jsonArss UpdateString: @"service" value: @"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" value: @"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" value: @"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" value: @"demoprod"];

// ARSS account username.
[jsonArss UpdateString: @"user" value: @"YOUR_ARSS_USERNAME"];

// ARSS account password.
[jsonArss UpdateString: @"userPWD" value: @"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" value: @"https://app1.firma-remota.it/ArubaSignerService/webresources/signerservice"];

success = [cert SetCloudSigner: jsonArss];
if (success == NO) {
    NSLog(@"%@",cert.LastErrorText);
    return;
}

// Associate the certificate with the PDF object.
// All subsequent signing operations will use this certificate.
success = [pdf SetSigningCert: cert];
if (success == NO) {
    NSLog(@"%@",pdf.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.
success = [pdf SignPdf: json outFilePath: @"qa_output/hello_ltv_signed.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf.LastErrorText);
    return;
}

NSLog(@"%@",@"The PDF has been successfully cryptographically signed with long-term validation.");