(Delphi ActiveX) Encrypt File using X.509 Certificate using AES in CBC Mode

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.)

Chilkat for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
crypt: TChilkatCrypt2;
cert: TChilkatCert;
success: Integer;

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

crypt := TChilkatCrypt2.Create(Self);

// 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.
cert := TChilkatCert.Create(Self);
success := cert.LoadFromFile('qa_data/certs/testCert.cer');
if (success <> 1) then
  begin
    Memo1.Lines.Add(cert.LastErrorText);
    Exit;
  end;

success := crypt.SetEncryptCert(cert.ControlInterface);
if (success <> 1) then
  begin
    Memo1.Lines.Add(crypt.LastErrorText);
    Exit;
  end;

// 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 1 to
// use RSAES_OAEP.  (We'll leave it set at the default value of 0)
crypt.OaepPadding := 0;

// 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 <> 1) then
  begin
    Memo1.Lines.Add(crypt.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('Finished.');
end;