(.NET Core C#) Duplicate OpensSSL Command that Decrypts Binary DER

This example duplicates the following:

openssl smime -decrypt -in INPUT_FILE -inform der -binary -out OUTPUT_FILE -recip PEM_CERT_AND_KEY -passin pass:PRIVKEY_PASSWORD

Note: Although "smime" is the OpenSSL command, we're not really dealing with S/MIME. The arguments "-inform der -binary" indicate that the input is simply the binary DER (i.e. the PKCS7 binary encrypted object). The output can be any type of file (whatever was encrypted).

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

Chilkat.Crypt2 crypt = new Chilkat.Crypt2();

crypt.CryptAlgorithm = "pki";

Chilkat.Pem pem = new Chilkat.Pem();
bool success = pem.LoadPemFile("qa_data/pem/myPem.pem","password");
if (success != true) {
    Debug.WriteLine(pem.LastErrorText);
    return;
}

Chilkat.PrivateKey privkey = pem.GetPrivateKey(0);
if (pem.LastMethodSuccess != true) {
    Debug.WriteLine(pem.LastErrorText);
    return;
}

Chilkat.Cert cert = pem.GetCert(0);
if (pem.LastMethodSuccess != true) {

    Debug.WriteLine(pem.LastErrorText);
    return;
}

success = crypt.SetDecryptCert2(cert,privkey);
if (success != true) {

    Debug.WriteLine(crypt.LastErrorText);
    return;
}

success = crypt.CkDecryptFile("qa_data/infile.enc","qa_output/outfile.dat");
if (success != true) {
    Debug.WriteLine(crypt.LastErrorText);
    return;
}

Debug.WriteLine("Success.");