Making and Extracting the content of a .p7m file.

procedure TForm1.btnSignClick(Sender: TObject);
var src, dst: TStream; cert: TclCertificate;
begin
    src := nil;
    dst := nil;
    if (cbCertificate.ItemIndex < 0) then Exit;
    
    try
        src := TFileStream.Create(edtSourceFile.Text, fmOpenRead or fmShareDenyWrite);
        dst := TFileStream.Create(edtDestinationFile.Text, fmCreate);
        cert := clCertificateStore1.Items[cbCertificate.ItemIndex];
        clEncryptor1.Sign(src, dst, False, True, cert, nil);

        ShowMessage('Done');
    finally
        dst.Free();
        src.Free();
    end;
end;

procedure TForm1.btnLoadCertificateClick(Sender: TObject);
var i: Integer;
begin
    clCertificateStore1.Close();
    cbCertificate.Clear();

    case cbCertificateLocation.ItemIndex of
        0: clCertificateStore1.ImportFromPFX(edtCertifFileName.Text, edtCertifPassword.Text);
        1: clCertificateStore1.Open('MY');
    end;

    for i := 0 to clCertificateStore1.Items.Count - 1 do
    begin
        if (clCertificateStore1.Items[i].FriendlyName <> '') then
        begin
            cbCertificate.Items.Add(clCertificateStore1.Items[i].FriendlyName);
        end else
        begin
            cbCertificate.Items.Add(clCertificateStore1.Items[i].IssuedTo);
        end;
    end;

    if (cbCertificate.Items.Count > 0) then
    begin
        cbCertificate.ItemIndex := 0;
    end;
end;

procedure TForm1.btnVerifyFileClick(Sender: TObject);
begin clEncryptor1.ExtractCertificates(edtSRC.Text);
    if clEncryptor1.ExtractedCertificates.Items.Count > 0 then
    begin
        lbResult.Items.Add(clEncryptor1.ExtractedCertificates.Items[0].IssuedTo);
    end;
    clEncryptor1.VerifyEnveloped(edtSRC.Text, edtDST.Text);
end;