Objective-C

Certify a PDF and Lock the Entire Document

See more PDF Signatures Examples

This example demonstrates how to a sign a certify a PDF and lock the entire document. Normally this is intended to seal the document with a final approving (or dissapproving) signature; usually after a review workflow is completed and normally reserved for the creator or author of a document. 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 certified and locked.
//  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]];

//  The only coding difference with certifying and locking a PDF
//  as compared with an approval signature (also known as recipient signature)
//  is to add the "lockAfterSigning" and "docMDP.add" to the json.
[json UpdateBool: @"lockAfterSigning" value: YES];
[json UpdateBool: @"docMDP.add" value: YES];

//  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."];

//  Load the signing certificate. (Use your own certificate.)
CkoCert *cert = [[CkoCert alloc] init];
success = [cert LoadPfxFile: @"qa_data/pfx/myPdfSigningCert.pfx" password: @"secret"];
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.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf.LastErrorText);
    return;
}

NSLog(@"%@",@"The PDF has been successfully certified and locked.");