(Delphi ActiveX) Decrypt a .p7m File (using a PFX)

Delphi ActiveX sample code showing how to decrypt a .p7m using a .p12 / .pfx certificate w/ private key.

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;
pfxPath: WideString;
pfxPassword: WideString;
success: Integer;
inPath: WideString;
outPath: WideString;

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

crypt := TChilkatCrypt2.Create(Self);

// Use a digital certificate and private key from a PFX file (.pfx or .p12).
pfxPath := 'myCertAndKey.pfx';
pfxPassword := 'test123';

success := crypt.AddPfxSourceFile(pfxPath,pfxPassword);
if (success <> 1) then
  begin
    Memo1.Lines.Add(crypt.LastErrorText);
    Exit;
  end;

// Set the  outPath to whatever is appropriate.
// If you are decrypting a PDF, your output might be "out.pdf"...
inPath := 'smime.p7m';
outPath := 'original.txt';

// Indicate that we're doing public key decryption (i.e. PKCS7)
crypt.CryptAlgorithm := 'pki';

success := crypt.CkDecryptFile(inPath,outPath);
if (success = 0) then
  begin
    Memo1.Lines.Add(crypt.LastErrorText);
    Exit;
  end;

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