(C#) Duplicate openssl smime -encrypt -binary -aes-256-cbc -in some_file.dat -out some_file.dat.enc -outform DER cert.crt

Demonstrates how to encrypt to binary DER using 256-bit AES (CBC mode) as the underlying symmetric encryption algorithm, to produce PKCS7 enveloped data (binary DER).

Duplicates the following openssl command:

openssl smime -encrypt -binary -aes-256-cbc -in some_file.dat -out some_file.dat.enc -outform DER cert.crt

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.Cert cert = new Chilkat.Cert();
bool success = cert.LoadFromFile("qa_data/openssl/EE.cer");
if (success == false) {
    Debug.WriteLine(cert.LastErrorText);
    return;
}

Chilkat.BinData bd = new Chilkat.BinData();
success = bd.LoadFile("qa_data/openssl/hello.txt");
// Assuming success..

Chilkat.Crypt2 crypt = new Chilkat.Crypt2();
success = crypt.SetEncryptCert(cert);
if (success == false) {
    Debug.WriteLine(crypt.LastErrorText);
    return;
}

crypt.CryptAlgorithm = "PKI";

// Indicate the underlying symmetric encryption to be used:
crypt.Pkcs7CryptAlg = "aes";
crypt.KeyLength = 256;
crypt.CipherMode = "cbc";

success = crypt.CkEncryptFile("qa_data/openssl/hello.txt","qa_output/hello.txt.enc");
if (success == false) {
    Debug.WriteLine(crypt.LastErrorText);
    return;
}

Debug.WriteLine("Success.");