(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).

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

// 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.");