Visual C++ - Verify digital signature and decrypt email - S/MIME¶

#include "stdafx.h"
#include <Windows.h>

#include "eagetmailobj.tlh"
using namespace EAGetMailObjLib;

void ParseEmail(LPCTSTR lpszFile)
{
    try
    {
        IMailPtr oMail = NULL;
        oMail.CreateInstance(__uuidof(EAGetMailObjLib::Mail));
        oMail->LicenseCode = _T("TryIt");

        oMail->LoadFile(lpszFile, VARIANT_FALSE);

        if(oMail->IsEncrypted == VARIANT_TRUE)
        {
            // this email is encrypted, we decrypt it by user default certificate.
            // you can also use specified certificate like this
            // ICertificatePtr oCert = NULL;
            // oCert.CreateInstance("EAGetMailObj.Certificate");
            // oCert->LoadFromFile(_T("c:\\test.pfx"), _T("pfxpassword"), CRYPT_USER_KEYSET);
            // oMail = oMail->Decrypt(oCert);
            oMail = oMail->Decrypt(NULL);
        }

        if(oMail->IsSigned == VARIANT_TRUE)
        {
            // This email is digital signed.
            ICertificatePtr oCert = oMail->VerifySignature();
            _tprintf(_T("This email contains a valid digital signature.\r\n"));
            // You can add the certificate to your certificate storage like this
            // oCert->AddToStore(CERT_SYSTEM_STORE_CURRENT_USER,
            // _T("addressbook"));
            // then you can use send the encrypted email back to this sender.
        }

        // Parse email sender
        _tprintf(_T("From: %s\r\n"), (const TCHAR*)oMail->From->Address);

        IAddressCollectionPtr addressList = oMail->ToList;
        for(long i = 0; i < addressList->Count; i++)
        {
            IMailAddressPtr oAddr = addressList->GetItem(i);
            _tprintf(_T("To: %s<%s>\r\n"), (TCHAR*)oAddr->Name, (TCHAR*)oAddr->Address);
        }

        addressList = oMail->CcList;
        for(long i = 0; i < addressList->Count; i++)
        {
            IMailAddressPtr  oAddr = addressList->GetItem(i);
            _tprintf(_T("Cc: %s<%s>\r\n"), (TCHAR*)oAddr->Name, (TCHAR*)oAddr->Address);
        }

        // Parse email subject
        _tprintf(_T("Subject: %s\r\n"), (const TCHAR*)oMail->Subject);

        // Parse email text body
        _tprintf(_T("TextBody: %s\r\n"), (const TCHAR*)oMail->TextBody);

        // Parse email HTML body
        _tprintf(_T("HtmlBody: %s\r\n"), (const TCHAR*)oMail->HtmlBody);

        // Parse attachment
        IAttachmentCollectionPtr attachments = oMail->AttachmentList;
        for(long i = 0; i < attachments->Count; i++)
        {
            IAttachmentPtr pAtt = attachments->GetItem(i);
            _tprintf(_T("Attachment: %s\r\n"), (const TCHAR*)pAtt->Name);
        }
    }
    catch(_com_error &ep)
    {
        _tprintf(_T("Error: %s\r\n"), (const TCHAR*)ep.Description());
    }
}

int _tmain(int argc, _TCHAR* argv[])
{
    // Initialize COM environment
    ::CoInitialize(NULL);

    ParseEmail(_T("c:\\my folder\\test.eml"));

    return 0;
}