Sample code for 30+ languages & platforms
Unicode C++

Duplicate OpensSSL to Sign File and Output Binary DER

See more OpenSSL Examples

This example duplicates the following:
openssl smime -sign -in INPUT.xml -signer SIGN.PEM -passin pass:MYPASS -outform der -binary -nodetach -out SIGNED.P7M

Note: Although "smime" is the OpenSSL command, it's not actually producing S/MIME. The arguments "-outform der -binary" indicates that the output is binary DER (i.e. the PKCS7 binary signature). The input can be any type of file: XML, PDF, JPG, ... *anything*...

Chilkat Unicode C++ Downloads

Unicode C++
#include <CkCrypt2W.h>
#include <CkPemW.h>
#include <CkPrivateKeyW.h>
#include <CkCertW.h>

void ChilkatSample(void)
    {
    bool success = false;

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

    CkCrypt2W crypt;

    // Load the PEM containing cert + private key.
    CkPemW pem;
    success = pem.LoadPemFile(L"qa_data/pem/myPem.pem",L"password");
    if (success == false) {
        wprintf(L"%s\n",pem.lastErrorText());
        return;
    }

    CkPrivateKeyW privkey;
    success = pem.PrivateKeyAt(0,privkey);
    if (success == false) {
        wprintf(L"%s\n",pem.lastErrorText());
        return;
    }

    CkCertW cert;
    success = pem.CertAt(0,cert);
    if (success == false) {
        wprintf(L"%s\n",pem.lastErrorText());
        return;
    }

    success = crypt.SetSigningCert2(cert,privkey);
    if (success == false) {
        wprintf(L"%s\n",crypt.lastErrorText());
        return;
    }

    // Alternatively, we could use a .pfx/.p12 file.
    // (Chilkat also supports other formats/sources for cert/private keys...)
    CkCertW certFromP12;
    success = certFromP12.LoadPfxFile(L"qa_data/p12/myP12.p12",L"password");
    if (success == false) {
        wprintf(L"%s\n",certFromP12.lastErrorText());
        return;
    }

    // The certificate, when loaded from a .pfx/.p12, will automatically 
    // include the associated private key, assuming it's present in the .p12.
    // We don't have to explicitly provide the private key as in the
    // lines of code above that use the PEM file.
    success = crypt.SetSigningCert(certFromP12);
    if (success == false) {
        wprintf(L"%s\n",crypt.lastErrorText());
        return;
    }

    // Create the opaque signature (PKCS7 binary DER that contains both the signature and original file data).
    success = crypt.CreateP7M(L"qa_data/infile.anything",L"qa_output/outfile.p7m");
    if (success == false) {
        wprintf(L"%s\n",crypt.lastErrorText());
        return;
    }

    wprintf(L"Success.\n");
    }