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Email can be encrypted in real-time by storing email data files in a Truecrypt volume that must be mounted before using the email program.

Leo, it seems like the most important on-the-fly encryption that TrueCrypt could provide would be immediate encryption of email. By this, I mean email downloaded on to a hard drive; not stored on Gmail, Yahoo, or Hotmail. The misery of email security and privacy management must drive millions of people crazy besides me. Even if you have every system and file hidden on TrueCrypt, the encryption is not updated in real time. This, of course, means that to be truly confidential and thief protected, a laptop or other device has to have its email folders exported and then encrypted on TrueCrypt on a daily basis. Do you know or foresee the development of any application that would make immediate email encryption as simple as TrueCrypt makes encryption of all other files?

In this excerpt from Answercast #35, I look at encrypting email real-time by storing your email folders in a Truecrypt volume. They are only accessible after mounting the volume.

Encrypting email

So I'm not really sure what it is you're referring to here.

On my Dell laptop, on my PC desktop, I have my email folders stored on a TrueCrypt volume.

So I can't even see my email, I can't get to my email unless I have the TrueCrypt volume mounted. Once it's mounted, Thunderbird happily puts all of its email onto that volume. And it is, in fact, encrypted in real time.

  • It's visible unencrypted as long as the volume is mounted.

  • As soon as the volume is dismounted, then the email is present – but it is completely and totally encrypted.

So, I'm not really sure exactly what it is you're referring to.

Exporting to Truecrypt?

There was no export/copy operation necessary to get encrypted storage of my own email on my own PC. And I know that the same thing could very well be done on the Mac as well.

And (in fact, as I think about it) I may end up having to do exactly that with my new Macintosh.

So the short answer is:

  • You can do what you're looking for right now using TrueCrypt. No changes necessary.

Native encryption

The other approach that you may consider (if TrueCrypt for whatever reason is too cumbersome) is to use an email program that allows the option of storing its email natively encrypted.

Now, there may be others, but the only one that I'm aware of is Outlook: Microsoft Outlook that comes with Microsoft Office.

If you look at Properties for a PST file within Outlook, there is an option to specify an encryption password. That will cause the PST itself to be encrypted.

  • Don't forget the password!

I actually don't know how strong an encryption it really is.

I tend to avoid application-specific encryption mechanisms because typically, they are after-thoughts or add-ons. They may not be up to the same level of encryption standards that something like, say, TrueCrypt would be. But it is there and I know that it is completely transparent once you have it turned on.

So those are two options for you.

  • I think TrueCrypt is a viable solution for the kind of thing that you are asking about.

  • If not, some email programs themselves have the encryption ability built right in.

Article C5584 - July 14, 2012 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

Katie Campbell
July 16, 2012 7:54 AM

Leo, have you heard of Ziptr? We have real-time, bi-directional, bank-level encryption as the backbone of our secure communication solution. All messages and files sent in Ziptr are auto-encrypted, synced, and backed up on your system and in the cloud. It's free for individuals

Glyn Duggan
July 18, 2012 3:33 AM


I too use Thunderbird, but not being good at these things I can't see what exactly the procedure is for using TrueCrypt to encrypt its folders . Can you give some further details?

In short: locate your Thundebird profile folder (, create a TrueCrypt volume that is at least as big as the profile folder contents, preferably much (2-3x) bigger. Mount that TrueCrypt volume. Move your Thunderbird profile to that volume. You're done. (How do I move my Thunderbird-based email from one machine to another? while technically slightly different will also help understanding what you're up to.)

July 18, 2012 4:04 AM

Not sure if Thunderbird would help this problem, but...I'm using Windows Live Mail. WLM also has a Tools/Options/Advanced/Maintenance/Store Folder operation for (I thought) moving the entire program. I moved it to my Truecrypt volume--watched the Windows Green Snaky-Line copy all the files. *Then* I saw that all I had done was duplicate WLM; it still exists, fully operational, on the C: drive. So unfortunately, I'm back to square one.

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