(Unicode C) Sign a Byte Array to Create an Opaque Signature in a Byte Array

Signs data contained in a byte array to produce an opaque signature (also in a byte array). An opaque signature is a PKCS7 signature (also known as CAdES) that embeds the signed data. Also shows how to verify the signature and extract the original data.

Chilkat C/C++ Library Downloads
MS Visual C/C++ Linux/CentOS C/C++ Alpine Linux C/C++ MAC OS X C/C++	armhf/aarch64 C/C++ C++ Builder iOS C/C++ Android C/C++	Solaris C/C++ MinGW C/C++

#include <C_CkCertW.h>
#include <C_CkFileAccessW.h>
#include <C_CkByteData.h>
#include <C_CkCrypt2W.h>

void ChilkatSample(void)
    {
    HCkCertW cert;
    BOOL success;
    HCkFileAccessW fac;
    HCkByteData fileBytes;
    HCkCrypt2W crypt;
    HCkByteData sigBytes;
    HCkByteData originalData;

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

    cert = CkCertW_Create();
    success = CkCertW_LoadPfxFile(cert,L"qa_data/pfx/cert_test123.pfx",L"test123");
    if (success == FALSE) {
        wprintf(L"%s\n",CkCertW_lastErrorText(cert));
        CkCertW_Dispose(cert);
        return;
    }

    fac = CkFileAccessW_Create();

    fileBytes = CkByteData_Create();
    success = CkFileAccessW_ReadEntireFile(fac,L"qa_data/pdf/sample.pdf",fileBytes);
    if (CkFileAccessW_getLastMethodSuccess(fac) != TRUE) {
        wprintf(L"%s\n",CkFileAccessW_lastErrorText(fac));
        CkCertW_Dispose(cert);
        CkFileAccessW_Dispose(fac);
        CkByteData_Dispose(fileBytes);
        return;
    }

    crypt = CkCrypt2W_Create();

    success = CkCrypt2W_SetSigningCert(crypt,cert);

    // We can sign any type of file.

    sigBytes = CkByteData_Create();
    success = CkCrypt2W_OpaqueSignBytes(crypt,fileBytes,sigBytes);
    if (CkCrypt2W_getLastMethodSuccess(crypt) != TRUE) {
        wprintf(L"%s\n",CkCrypt2W_lastErrorText(crypt));
        CkCertW_Dispose(cert);
        CkFileAccessW_Dispose(fac);
        CkByteData_Dispose(fileBytes);
        CkCrypt2W_Dispose(crypt);
        CkByteData_Dispose(sigBytes);
        return;
    }

    success = CkFileAccessW_WriteEntireFile(fac,L"qa_output/sample.pdf.p7m",sigBytes);
    if (CkFileAccessW_getLastMethodSuccess(fac) != TRUE) {
        wprintf(L"%s\n",CkFileAccessW_lastErrorText(fac));
        CkCertW_Dispose(cert);
        CkFileAccessW_Dispose(fac);
        CkByteData_Dispose(fileBytes);
        CkCrypt2W_Dispose(crypt);
        CkByteData_Dispose(sigBytes);
        return;
    }

    // We can verify the opaque signature and extract the original data like this
    originalData = CkByteData_Create();
    success = CkCrypt2W_OpaqueVerifyBytes(crypt,sigBytes,originalData);
    if (CkCrypt2W_getLastMethodSuccess(crypt) != TRUE) {
        wprintf(L"%s\n",CkCrypt2W_lastErrorText(crypt));
        CkCertW_Dispose(cert);
        CkFileAccessW_Dispose(fac);
        CkByteData_Dispose(fileBytes);
        CkCrypt2W_Dispose(crypt);
        CkByteData_Dispose(sigBytes);
        CkByteData_Dispose(originalData);
        return;
    }

    success = CkFileAccessW_WriteEntireFile(fac,L"qa_output/sample.pdf",originalData);
    if (CkFileAccessW_getLastMethodSuccess(fac) != TRUE) {
        wprintf(L"%s\n",CkFileAccessW_lastErrorText(fac));
        CkCertW_Dispose(cert);
        CkFileAccessW_Dispose(fac);
        CkByteData_Dispose(fileBytes);
        CkCrypt2W_Dispose(crypt);
        CkByteData_Dispose(sigBytes);
        CkByteData_Dispose(originalData);
        return;
    }

    wprintf(L"Signature is verified and the original data was extracted.\n");


    CkCertW_Dispose(cert);
    CkFileAccessW_Dispose(fac);
    CkByteData_Dispose(fileBytes);
    CkCrypt2W_Dispose(crypt);
    CkByteData_Dispose(sigBytes);
    CkByteData_Dispose(originalData);

    }