(Delphi ActiveX) IMAP Download and Verify Signed MIME

Downloads the unmodified MIME of a digitally signed email, saves the .p7s signature (and other MIME parts), then loads the email into a Chilkat email object (which unwraps the S/MIME and verifies the signature) and then saves attachments (if the MIME parts were not already saved).

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
imap: TChilkatImap;
success: Integer;
sbMime: TChilkatStringBuilder;
mime: TChilkatMime;
alreadySavedParts: Integer;
sa: ICkStringArray;
numFiles: Integer;
i: Integer;
email: TChilkatEmail;
cert: IChilkatCert;

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

imap := TChilkatImap.Create(Self);

// Connect to an IMAP server.
// Use TLS
imap.Ssl := 1;
imap.Port := 993;
success := imap.Connect('imap.someMailServer.com');
if (success <> 1) then
  begin
    Memo1.Lines.Add(imap.LastErrorText);
    Exit;
  end;

success := imap.Login('myLogin','myPassword');
if (success <> 1) then
  begin
    Memo1.Lines.Add(imap.LastErrorText);
    Exit;
  end;

// Select an IMAP mailbox
success := imap.SelectMailbox('Inbox');
if (success <> 1) then
  begin
    Memo1.Lines.Add(imap.LastErrorText);
    Exit;
  end;

// Download the 1st email (as MIME) in the Inbox by sequence number.
sbMime := TChilkatStringBuilder.Create(Self);
success := imap.FetchSingleAsMimeSb(1,0,sbMime.ControlInterface);
if (success <> 1) then
  begin
    Memo1.Lines.Add(imap.LastErrorText);
    Exit;
  end;

// Load it into a MIME object and check to see if it is signed
mime := TChilkatMime.Create(Self);
mime.LoadMimeSb(sbMime.ControlInterface);
alreadySavedParts := 0;
if (mime.ContainsSignedParts() = 1) then
  begin

    // This will save the .p7s and other parts...
    sa := mime.ExtractPartsToFiles('qa_output');
    if (mime.LastMethodSuccess = 1) then
      begin
        numFiles := sa.Count;
        i := 0;
        while i < numFiles do
          begin
            Memo1.Lines.Add('Created: ' + sa.GetString(i));
            i := i + 1;
          end;

        alreadySavedParts := 1;
      end;
  end;

// Load the MIME into an Email object.  This unwraps the security layers and verifies signatures.
email := TChilkatEmail.Create(Self);
email.SetFromMimeSb(sbMime.ControlInterface);

if (email.ReceivedSigned = 1) then
  begin

    Memo1.Lines.Add('This email was signed.');

    // Check to see if the signatures were verified.
    if (email.SignaturesValid = 1) then
      begin
        Memo1.Lines.Add('Digital signature(s) verified.');

        Memo1.Lines.Add('Signer: ' + email.SignedBy);

        // The certificate used for signing may be obtained
        // by calling email.GetSignedByCert.
        cert := email.GetSignedByCert();
        if (email.LastMethodSuccess <> 1) then
          begin
            Memo1.Lines.Add('Failed to get signing certificate object.');
          end
        else
          begin
            Memo1.Lines.Add('Signing cert: ' + cert.SubjectCN);

          end;
      end;

  end
else
  begin
    Memo1.Lines.Add('Digital signature verification failed.');
  end;

if (alreadySavedParts <> 1) then
  begin
    email.SaveAllAttachments('qa_output');
  end;
end;