Objective-C

Create CMS Signed File (PDF) with Multiple Signing Certificates

See more Digital Signatures Examples

Demonstrates how to sign a file by adding multiple signatures (multiple certificates). This example signs a PDF file to produce an output file that is a CMS signature wrapping the original PDF. (Note: This is different than modifying a PDF by injecting a signature into the PDF file format.)

Note: This example requires Chilkat v9.5.0.83 or greater.

Objective-C

#import <CkoCrypt2.h>
#import <CkoCert.h>
#import <NSString.h>

BOOL success = NO;

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

CkoCrypt2 *crypt = [[CkoCrypt2 alloc] init];

//  ------------ This example requires Chilkat v9.5.0.83 or greater.

CkoCert *cert1 = [[CkoCert alloc] init];
success = [cert1 LoadPfxFile: @"qa_data/pfx/cert_test123.pfx" password: @"test123"];
if (success != YES) {
    NSLog(@"%@",cert1.LastErrorText);
    return;
}

CkoCert *cert2 = [[CkoCert alloc] init];
success = [cert2 LoadPfxFile: @"qa_data/pfx/test_secret.pfx" password: @"secret"];
if (success != YES) {
    NSLog(@"%@",cert2.LastErrorText);
    return;
}

//  ------------ This example requires Chilkat v9.5.0.83 or greater.

//  Tell the crypt component to use both certificates for signing. 
//  When we create the signature, it will be signed by both certificates.
success = [crypt AddSigningCert: cert1];
if (success != YES) {
    NSLog(@"%@",crypt.LastErrorText);
    return;
}

success = [crypt AddSigningCert: cert2];
if (success != YES) {
    NSLog(@"%@",crypt.LastErrorText);
    return;
}

//  The CadesEnabled property applies to all methods that create PKCS7 signatures. 
//  To create a CAdES-BES signature, set this property equal to true. 
crypt.CadesEnabled = YES;

crypt.HashAlgorithm = @"sha256";

//  We can sign any type of file, creating a .p7s as output.
//  The .p7s contains the signature and also embeds the data of the file that is signed.
NSString *inFile = @"qa_data/pdf/sample.pdf";
NSString *p7sFile = @"qa_output/sample.pdf.p7s";

//  Create the CAdES-BES attached signature, which contains the original data.
//  Note: Chilkat's function naming is not accurate.  CreateP7M creates a PKCS7 signature where the signed file
//  is contained within the signature.  CreateP7S creates a detached PKCS7 signature where the signed file
//  is NOT contained within the signature.  We want the data to be contained in the signature, therefore
//  we call CreateP7M even though we are naming our output file .p7s.
success = [crypt CreateP7M: inFile p7mPath: p7sFile];
if (success == NO) {
    NSLog(@"%@",crypt.LastErrorText);
    return;
}

//  Verify the .p7s file and extract the original file from the .p7s. 
NSString *extractedToFilePath = @"qa_output/sample.pdf";
success = [crypt VerifyP7M: p7sFile destPath: extractedToFilePath];
if (success == NO) {
    NSLog(@"%@",crypt.LastErrorText);
    return;
}

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