(Objective-C) Convert PDF to pdf.p7s (Digitally Signed)

Demonstrates how to convert a PDF into a .p7s file that contains the PDF within a PKCS7 signature (the .p7s format).

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

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

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

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

// Tell the crypt component to use this cert.
success = [crypt SetSigningCert: cert];
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";

// -----------------------------------------------------------------------------------------
// Also see Chilkat's online tool to examine a .p7m and generate code to duplicate the .p7m
// -----------------------------------------------------------------------------------------

// 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!");