(Delphi DLL) 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 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, Imap, Email, StringBuilder, Mime, Cert, StringArray;

...

procedure TForm1.Button1Click(Sender: TObject);
var
imap: HCkImap;
success: Boolean;
sbMime: HCkStringBuilder;
mime: HCkMime;
alreadySavedParts: Boolean;
sa: HCkStringArray;
numFiles: Integer;
i: Integer;
email: HCkEmail;
cert: HCkCert;

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

imap := CkImap_Create();

// Connect to an IMAP server.
// Use TLS
CkImap_putSsl(imap,True);
CkImap_putPort(imap,993);
success := CkImap_Connect(imap,'imap.someMailServer.com');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkImap__lastErrorText(imap));
    Exit;
  end;

success := CkImap_Login(imap,'myLogin','myPassword');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkImap__lastErrorText(imap));
    Exit;
  end;

// Select an IMAP mailbox
success := CkImap_SelectMailbox(imap,'Inbox');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkImap__lastErrorText(imap));
    Exit;
  end;

// Download the 1st email (as MIME) in the Inbox by sequence number.
sbMime := CkStringBuilder_Create();
success := CkImap_FetchSingleAsMimeSb(imap,1,False,sbMime);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkImap__lastErrorText(imap));
    Exit;
  end;

// Load it into a MIME object and check to see if it is signed
mime := CkMime_Create();
CkMime_LoadMimeSb(mime,sbMime);
alreadySavedParts := False;
if (CkMime_ContainsSignedParts(mime) = True) then
  begin

    // This will save the .p7s and other parts...
    sa := CkMime_ExtractPartsToFiles(mime,'qa_output');
    if (CkMime_getLastMethodSuccess(mime) = True) then
      begin
        numFiles := CkStringArray_getCount(sa);
        i := 0;
        while i < numFiles do
          begin
            Memo1.Lines.Add('Created: ' + CkStringArray__getString(sa,i));
            i := i + 1;
          end;

        CkStringArray_Dispose(sa);
        alreadySavedParts := True;
      end;
  end;

// Load the MIME into an Email object.  This unwraps the security layers and verifies signatures.
email := CkEmail_Create();
CkEmail_SetFromMimeSb(email,sbMime);

if (CkEmail_getReceivedSigned(email) = True) then
  begin

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

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

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

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

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

if (alreadySavedParts <> True) then
  begin
    CkEmail_SaveAllAttachments(email,'qa_output');
  end;

CkImap_Dispose(imap);
CkStringBuilder_Dispose(sbMime);
CkMime_Dispose(mime);
CkEmail_Dispose(email);

end;