Unwrap S/MIME Security Layers

Download Chilkat MIME ActiveX

Demonstrates how to unwrap the security layers of a signed and/or encrypted S/MIME message.

uses
    Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
    Dialogs, StdCtrls,
    CHILKATMIMELib_TLB,
    CHILKATCERTIFICATELib_TLB,
    OleCtrls;

...

procedure TForm1.Button1Click(Sender: TObject);
var
i: Integer;
mime: CHILKATMIMELib_TLB.IChilkatMime;
success: Integer;
cert: CHILKATMIMELib_TLB.IChilkatCert;
numSignerCerts: Integer;
numEncryptCerts: Integer;

begin


mime := CoChilkatMime.Create();

success := mime.UnlockComponent('Anything for 30-day trial');
if (success = 0) then
  begin
    ShowMessage(mime.LastErrorText);
    Exit;
  end;

//  Note: Your S/MIME file may have a different file extension.
success := mime.LoadMimeFile('smime.eml');
if (success = 0) then
  begin
    ShowMessage(mime.LastErrorText);
    Exit;
  end;

//  Unwrap any security layers so that the resultant MIME
//  is the original message before signing and/or encrypting
//  was applied.  UnwrapSecurity returns 1 if
//  there was nothing to unwrap, or if all signatures were verified,
//  and all decryptions succeeded.
success := mime.UnwrapSecurity();
if (success = 0) then
  begin
    ShowMessage(mime.LastErrorText);
    Exit;
  end;

//  Save the unwrapped S/MIME:
success := mime.SaveMime('unwrapped.eml');
if (success = 0) then
  begin
    ShowMessage(mime.LastErrorText);
    Exit;
  end;

//  Let's see if the MIME was signed, and if so whether
//  the signature(s) were verified.  Also, examine the certificate
//  used for signing.

//  Unwrapping the security sets the NumSignerCerts property.
//  If it is non-zero, then signatures were unwrapped...
Memo1.Lines.Add('Signer Certificates: ');
numSignerCerts := mime.NumSignerCerts;
if (numSignerCerts > 0) then
  begin
    for i := 0 to numSignerCerts - 1 do
      begin
        cert := mime.GetSignerCert(i) As CHILKATMIMELib_TLB.IChilkatCert;
        if (not (cert = nil )) then
          begin
            //  Show the cert's common name.
            Memo1.Lines.Add(cert.SubjectCN);
          end;
      end;

  end;

//  Now check to see if anything was decrypted.
Memo1.Lines.Add('Encryption Certificates: ');
numEncryptCerts := mime.NumEncryptCerts;
if (numEncryptCerts > 0) then
  begin
    for i := 0 to numEncryptCerts - 1 do
      begin
        cert := mime.GetEncryptCert(i) As CHILKATMIMELib_TLB.IChilkatCert;
        if (not (cert = nil )) then
          begin
            //  Show the cert's common name.
            Memo1.Lines.Add(cert.SubjectCN);
          end;
      end;

  end;


end;