Delphi DLL

Duplicate openssl smime -decrypt -in some_file.dat.enc -binary -inform DER -inkey private.key -out some_file.dat

See more OpenSSL Examples

Demonstrates how to decrypt binary DER that was encrypted using the following openssl command:

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

Delphi DLL

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

...

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

begin
success := False;

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

// Duplicates the following openssl command:
// openssl smime -decrypt -in hello.txt.enc -binary -inform DER -inkey private.key -out hello.txt

cert := CkCert_Create();
success := CkCert_LoadFromFile(cert,'qa_data/openssl/EE.cer');
if (success = False) then
  begin
    Memo1.Lines.Add(CkCert__lastErrorText(cert));
    Exit;
  end;

bd := CkBinData_Create();
success := CkBinData_LoadFile(bd,'qa_data/openssl/EE.key');
// Assuming success..

privKey := CkPrivateKey_Create();
success := CkPrivateKey_LoadAnyFormat(privKey,bd,'');
if (success = False) then
  begin
    Memo1.Lines.Add(CkPrivateKey__lastErrorText(privKey));
    Exit;
  end;

crypt := CkCrypt2_Create();
success := CkCrypt2_SetDecryptCert2(crypt,cert,privKey);
if (success = False) then
  begin
    Memo1.Lines.Add(CkCrypt2__lastErrorText(crypt));
    Exit;
  end;

CkCrypt2_putCryptAlgorithm(crypt,'PKI');
success := CkCrypt2_CkDecryptFile(crypt,'qa_data/openssl/hello.txt.enc','qa_output/hello.txt');
if (success = False) then
  begin
    Memo1.Lines.Add(CkCrypt2__lastErrorText(crypt));
    Exit;
  end;

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

CkCert_Dispose(cert);
CkBinData_Dispose(bd);
CkPrivateKey_Dispose(privKey);
CkCrypt2_Dispose(crypt);

end;