(Delphi DLL) Extract PKCS7 from MIME and Decrypt

Extracts the base64-encoded PKCS7 body of a MIME message to a file, and then decrypts using Chilkat Crypt2.

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

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
mime: HCkMime;
success: Boolean;
crypt: HCkCrypt2;
inPath: PWideChar;
outPath: PWideChar;

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

mime := CkMime_Create();

success := CkMime_LoadMimeFile(mime,'c:/aaworkarea/EmailInBytes.txt');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkMime__lastErrorText(mime));
    Exit;
  end;

success := CkMime_SaveBody(mime,'c:/aaworkarea/smime.p7m');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkMime__lastErrorText(mime));
    Exit;
  end;

crypt := CkCrypt2_Create();

success := CkCrypt2_AddPfxSourceFile(crypt,'c:/aaworkarea/my.pfx','pfxPassword');
if (success = False) then
  begin
    Memo1.Lines.Add(CkCrypt2__lastErrorText(crypt));
    Exit;
  end;

// Indicate the public-key (PKCS7) encryption/decryption should be used:
CkCrypt2_putCryptAlgorithm(crypt,'pki');

inPath := 'c:/aaworkarea/smime.p7m';
outPath := 'c:/aaworkarea/decrypted.dat';

success := CkCrypt2_CkDecryptFile(crypt,inPath,outPath);
if (success = False) then
  begin
    Memo1.Lines.Add(CkCrypt2__lastErrorText(crypt));
    Exit;
  end;

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

CkMime_Dispose(mime);
CkCrypt2_Dispose(crypt);

end;