Objective-C

Sign a PDF using SmartCard or HSM (Hardware Security Module)

See more PDF Signatures Examples

This example demonstrates how to a sign a PDF using a smartcard or HSM (hardware security module).

Note: This example requires Chilkat v9.5.0.88 or greater.

Objective-C

#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 a PDF to be signed.
// The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
success = [pdf LoadFile: @"qa_data/pdf/hello.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf.LastErrorText);
    return;
}

// Options for signing are specified in JSON.
CkoJsonObject *json = [[CkoJsonObject alloc] init];

// In most cases, the signingCertificateV2 and signingTime attributes are required.
[json UpdateInt: @"signingCertificateV2" value: [NSNumber numberWithInt: 1]];
[json UpdateInt: @"signingTime" value: [NSNumber numberWithInt: 1]];

// Put the signature on page 1, top left
[json UpdateInt: @"page" value: [NSNumber numberWithInt: 1]];
[json UpdateString: @"appearance.y" value: @"top"];
[json UpdateString: @"appearance.x" value: @"left"];

// Use a font scale of 10.0
[json UpdateString: @"appearance.fontScale" value: @"10.0"];

// In this example, the appearance of the digital signature will contain three lines:
// 1) The signing certificate's common name
// 2) The current date/time
// 3) Some arbitrary text.
// The keyword "cert_cn" is replaced with the Certificate's Subject Common Name.
// The keyword "current_dt" is replaced with the current date/time.
// Any number of appearance text lines can be added.
[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: @"The crazy brown fox jumps over the lazy dog."];

// Use a certificate on a smartcard or USB token.
CkoCert *cert = [[CkoCert alloc] init];

// Provide the smartcard PIN.
// Set the smartcard PIN prior to calling LoadFromSmartcard.
// If the PIN is not explicitly provided here, the Windows OS should
// display a dialog for the PIN.
cert.SmartCardPin = @"123456";

// Load the certificate on the smartcard currently in the reader (or on the USB token).
// Pass an empty string to allow Chilkat to automatically choose the CSP (Cryptographi Service Provider).
// See Load Certificate on Smartcard for information about explicitly selecting a particular CSP.
success = [cert LoadFromSmartcard: @""];
if (success == NO) {
    NSLog(@"%@",cert.LastErrorText);
    return;
}

// Tell the pdf object to use the certificate for signing.
success = [pdf SetSigningCert: cert];
if (success == NO) {
    NSLog(@"%@",pdf.LastErrorText);
    return;
}

success = [pdf SignPdf: json outFilePath: @"qa_output/hello_signed_hsm.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf.LastErrorText);
    return;
}

NSLog(@"%@",@"The PDF has been successfully cryptographically signed using an HSM.");