Sample code for 30+ languages & platforms
Delphi DLL

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.)

Chilkat Delphi DLL Downloads

Delphi DLL
uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Cert, Crypt2;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
crypt: HCkCrypt2;
cert: HCkCert;

begin
success := False;

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

crypt := CkCrypt2_Create();

// Use public-key cryptography for encryption.
CkCrypt2_putCryptAlgorithm(crypt,'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 := CkCert_Create();
success := CkCert_LoadFromFile(cert,'qa_data/certs/testCert.cer');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkCert__lastErrorText(cert));
    Exit;
  end;

success := CkCrypt2_SetEncryptCert(crypt,cert);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkCrypt2__lastErrorText(crypt));
    Exit;
  end;

// Indicate the underlying bulk encryption algorithm to be used:
CkCrypt2_putPkcs7CryptAlg(crypt,'aes');
CkCrypt2_putKeyLength(crypt,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)
CkCrypt2_putOaepPadding(crypt,False);

// Everything is specified.  Now just encrypt...
// The output is PKCS7 in binary DER format.
success := CkCrypt2_CkEncryptFile(crypt,'qa_data/hamlet.xml','qa_output/hamlet.p7');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkCrypt2__lastErrorText(crypt));
    Exit;
  end;

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

CkCrypt2_Dispose(crypt);
CkCert_Dispose(cert);

end;