C#

Encrypt File using X.509 Certificate using AES in CBC Mode

See more Encryption Examples

Demonstrates how to encrypt a file using an X.509 Certificate's public key, where the underlying bulk encryption algorithm is 128-bit AES in CBC mode. (The underlying bulk encryption algorithm can be specified to be other algorithms/strengths.) C#

bool success = false;

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

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

// Use public-key cryptography for encryption.
crypt.CryptAlgorithm = "pki";

// Get an X.509 certificate to use for encrypting.
// Note: Chilkat provides many different ways of loading a certificate, from many different formats,
// or if on Windows, from the installed certificates on the system.
// This example simply loads a certificate from a file.
// Also, for encryption, only the public key is needed.  Digital certificates embed the public key
// within the X.509 format itself.  Therefore, if you have a certificate, you also have the public key.
Chilkat.Cert cert = new Chilkat.Cert();
success = cert.LoadFromFile("qa_data/certs/testCert.cer");
if (success != true) {
    Debug.WriteLine(cert.LastErrorText);
    return;
}

success = crypt.SetEncryptCert(cert);
if (success != true) {
    Debug.WriteLine(crypt.LastErrorText);
    return;
}

// Indicate the underlying bulk encryption algorithm to be used:
crypt.Pkcs7CryptAlg = "aes";
crypt.KeyLength = 128;

// Note: When doing public-key encryption the underlying bulk symmetric cipher mode will always be CBC. (at least with Chilkat...)

// There's one last option that could be set.  If is the RSA encryption encryption/padding scheme. 
// By default, RSAES_PKCS1-V1_5 is used.  If desired, the OaepPadding property could be set to true to
// use RSAES_OAEP.  (We'll leave it set at the default value of false)
crypt.OaepPadding = false;

// Everything is specified.  Now just encrypt...
// The output is PKCS7 in binary DER format.
success = crypt.CkEncryptFile("qa_data/hamlet.xml","qa_output/hamlet.p7");
if (success != true) {
    Debug.WriteLine(crypt.LastErrorText);
    return;
}

Debug.WriteLine("Finished.");