(Objective-C) PKCS11 Sign PDF using Certificate and Private Key on Smart Card / USB Token

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Sample code showing how to use PKCS11 to sign a PDF with a certificate and private key stored on a smart card or USB token.

Note: This example requires Chilkat v9.5.0.96 or later.

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#import <CkoPkcs11.h>
#import <NSString.h>
#import <CkoCert.h>
#import <CkoPdf.h>
#import <CkoJsonObject.h>

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

// Note: Chilkat's PKCS11 implementation runs on Windows, Linux, Mac OS X, and other supported operating systems.

CkoPkcs11 *pkcs11 = [[CkoPkcs11 alloc] init];

pkcs11.SharedLibPath = @"C:/Program Files (x86)/Gemalto/IDGo 800 PKCS#11/IDPrimePKCS1164.dll";
NSString *pin = @"0000";
int userType = 1;

// Establish a PKCS11 logged-on session using the driver (.so, .dylib, or .dll) as specified in the SharedLibPath above.
BOOL success = [pkcs11 QuickSession: [NSNumber numberWithInt: userType] pin: pin];
if (success == NO) {
    NSLog(@"%@",pkcs11.LastErrorText);
    return;
}

// Get the certificate (on the smart card) that has a private key.
// There are other ways to locate a certificate on the HSM.
// This example assumes there is a single certificate w/ private key.
CkoCert *cert = [[CkoCert alloc] init];
success = [pkcs11 FindCert: @"privateKey" partValue: @"" cert: cert];
if (success == YES) {
    NSLog(@"%@%@",@"Cert with private key: ",cert.SubjectCN);
}
else {
    NSLog(@"%@",@"No certificates having a private key were found.");
    success = [pkcs11 CloseSession];
    return;
}

// --------------------------------------------------------------------------
// At this point, we have the cert to be used for signing.
// Our PDF signing code is the same as for a cert obtained from any other source..

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

// Load a PDF to be signed.
success = [pdf LoadFile: @"qa_data/pdf/hello.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf.LastErrorText);
    success = [pkcs11 CloseSession];
    return;
}

CkoJsonObject *json = [[CkoJsonObject alloc] init];

[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"];
[json UpdateString: @"signingAlgorithm" value: @"pss"];
[json UpdateString: @"hashAlgorithm" value: @"sha256"];

int i = 0;
json.I = [NSNumber numberWithInt: i];
[json UpdateString: @"appearance.text[i]" value: @"Digitaly signed by: Xyz Widgets, Inc."];
i = i + 1;
json.I = [NSNumber numberWithInt: i];
[json UpdateString: @"appearance.text[i]" value: @"current_dt"];
i = i + 1;
json.I = [NSNumber numberWithInt: i];
[json UpdateString: @"appearance.text[i]" value: @"blah blah blah"];

// The certificate is internally linked to the Pkcs11 object, which is currently in an authenticated session.
success = [pdf SetSigningCert: cert];

success = [pdf SignPdf: json outFilePath: @"qa_output/out.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf.LastErrorText);
    success = [pkcs11 CloseSession];
    return;
}

// --------------------------------------------------------------------------

// Revert to an unauthenticated session by calling Logout.
success = [pkcs11 Logout];
if (success == NO) {
    NSLog(@"%@",pkcs11.LastErrorText);
    success = [pkcs11 CloseSession];
    return;
}

// When finished, close the session.
// It is important to close the session (memory leaks will occur if the session is not properly closed).
success = [pkcs11 CloseSession];
if (success == NO) {
    NSLog(@"%@",pkcs11.LastErrorText);
    return;
}

NSLog(@"%@",@"Success.");