(C) Create CMS Signed File (PDF) with Multiple Signing Certificates

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.

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#include <C_CkCrypt2.h>
#include <C_CkCert.h>

void ChilkatSample(void)
    {
    HCkCrypt2 crypt;
    HCkCert cert1;
    BOOL success;
    HCkCert cert2;
    const char *inFile;
    const char *p7sFile;
    const char *extractedToFilePath;

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

    crypt = CkCrypt2_Create();

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

    cert1 = CkCert_Create();
    success = CkCert_LoadPfxFile(cert1,"qa_data/pfx/cert_test123.pfx","test123");
    if (success != TRUE) {
        printf("%s\n",CkCert_lastErrorText(cert1));
        CkCrypt2_Dispose(crypt);
        CkCert_Dispose(cert1);
        return;
    }

    cert2 = CkCert_Create();
    success = CkCert_LoadPfxFile(cert2,"qa_data/pfx/test_secret.pfx","secret");
    if (success != TRUE) {
        printf("%s\n",CkCert_lastErrorText(cert2));
        CkCrypt2_Dispose(crypt);
        CkCert_Dispose(cert1);
        CkCert_Dispose(cert2);
        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 = CkCrypt2_AddSigningCert(crypt,cert1);
    if (success != TRUE) {
        printf("%s\n",CkCrypt2_lastErrorText(crypt));
        CkCrypt2_Dispose(crypt);
        CkCert_Dispose(cert1);
        CkCert_Dispose(cert2);
        return;
    }

    success = CkCrypt2_AddSigningCert(crypt,cert2);
    if (success != TRUE) {
        printf("%s\n",CkCrypt2_lastErrorText(crypt));
        CkCrypt2_Dispose(crypt);
        CkCert_Dispose(cert1);
        CkCert_Dispose(cert2);
        return;
    }

    // The CadesEnabled property applies to all methods that create PKCS7 signatures. 
    // To create a CAdES-BES signature, set this property equal to true. 
    CkCrypt2_putCadesEnabled(crypt,TRUE);

    CkCrypt2_putHashAlgorithm(crypt,"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.
    inFile = "qa_data/pdf/sample.pdf";
    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 = CkCrypt2_CreateP7M(crypt,inFile,p7sFile);
    if (success == FALSE) {
        printf("%s\n",CkCrypt2_lastErrorText(crypt));
        CkCrypt2_Dispose(crypt);
        CkCert_Dispose(cert1);
        CkCert_Dispose(cert2);
        return;
    }

    // Verify the .p7s file and extract the original file from the .p7s. 
    extractedToFilePath = "qa_output/sample.pdf";
    success = CkCrypt2_VerifyP7M(crypt,p7sFile,extractedToFilePath);
    if (success == FALSE) {
        printf("%s\n",CkCrypt2_lastErrorText(crypt));
        CkCrypt2_Dispose(crypt);
        CkCert_Dispose(cert1);
        CkCert_Dispose(cert2);
        return;
    }

    printf("Success!\n");


    CkCrypt2_Dispose(crypt);
    CkCert_Dispose(cert1);
    CkCert_Dispose(cert2);

    }