(Objective-C) Sign PDF using USB Token or Smartcard on iOS iPhone

Demonstrates how to sign a PDF using an HSM (USB token or smart card) connected to an iPhone.

Note: This example requires Chilkat v10.0.0 or greater.

Chilkat Objective-C Library Downloads MAC OS X (Cocoa) Libs iOS Libs

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

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

// When signing with a USB token or smartcard, the only coding difference is how the certificate
// gets loaded.  To load the default certificate from the connected USB token or smartcard, just call
// LoadFromSmartcard with an empty string argument.
// 
// This requires Chilkat v10.0.0 or later.
// 
// ------------------------------------------------------------------------------------------------------------------------------------------------------
// Important: In your Xcode project, you'll need to add the "com.apple.token" entitlement.
// Also, adding the com.apple.token in the "Project > Signing & Capabilities" will actually add $(AppIdentifierPrefix)com.apple.token, which does not work. 
// Edit the entitlements file directly and add only com.apple.token
// If using a Yubikey, you'll only find the certificate if it is added in the Yubikey app as Public.
// ------------------------------------------------------------------------------------------------------------------------------------------------------
CkoCert *cert = [[CkoCert alloc] init];
BOOL success = [cert LoadFromSmartcard: @""];
if (success == NO) {
    NSLog(@"%@",cert.LastErrorText);
    return;
}

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

// Wherever the PDF file is located..
// Modify to specify the actual path to the PDF.
NSString *pdfFilePath = @"....";

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

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

// Optionally create an LTV-enabled signature
[json UpdateBool: @"ltvOcsp" value: YES];

// Define the appearance of the signature.
[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: @"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."];

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

// Modify to specify the actual path to the output file (i.e. the signed PDF).
NSString *signedPdfOutputFilePath = @"....";
success = [pdf SignPdf: json outFilePath: signedPdfOutputFilePath];
if (success == NO) {
    NSLog(@"%@",pdf.LastErrorText);
    return;
}

NSLog(@"%@",@"PDF successfully signed using USB token on iOS");