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Re: Laptop Encryption Software
From: Gary Flynn <flynngn () JMU EDU>
Date: Mon, 5 Mar 2007 15:23:22 -0500

Lovaas,Steven wrote:

I'll touch on only one of your points for now: "why others were choosing commercial solutions over the native EFS". Not 
MS-bashing here, just pointing out some realities.

1) Without a PKI, XP allows you to turn your encrypted file into a digital brick. Looking to make the experience better from 2000 
(where you had to designate a recovery agent before you could turn on EFS, but the default recovery agent was the domain adminstrator 
account and you couldn't change that without a Microsoft CA), Microsoft changed XP to allow turning on EFS without specifying a 
recovery agent. The first user to do that would likely be a Vice President, and then he'd forget his password and one of us would 
be looking for work elsewhere :) So the way key management works between 2000, XP and Vista varies significantly... And if you have 
all three in your organization, you'll need to work carefully if you use the Microsoft approach without a PKI.

We are recommending against using EFS on Windows 2000 for the reason
you mentioned. In addition, I'd recommend against its use for any
sensitive data for additional reasons ( no built-in firewall, harder
to keep up to date, getting long in the tooth, better options freely
available depending on your campus licenses ).

Even without a PKI, the issues with EFS key escrow can be handled
in the installation procedure. It would back up the user account
keys and/or import a recovery agent certificate. We're planning
the latter.

The one area that could present a problem is that EFS uses a
unique symmetric key for each file and there is no mechanism
that I know of to export those keys. Nor would I want to
try to manage them if I could. I don't even think they're
handled by Microsoft's PKI.

I haven't looked into third party tools or their architectures
but they all have to have some way to archive encryption
key(s) external to the machine to have any value for data
recovery. To some extent then, they'd either use an external
PKI or the implement a single purpose one. Is it safe to assume
they all have their own central key repository?

Do they use unique encryption keys for each file like EFS
or is another architecture more common?

2) The Payment Card Industry Data Security Standards specify, in version 1.1 section 3.4, that Active Directory may not be used 
to manage logical access to protected files. While this is a single regulation, it supports the more generally held notion that 
if you really want to protect sensitive information (and that's why you want the encryption, right?) you need to keep it 
secure from hackers and worms that operate within a user's logged-in session. This points toward using third-party or custom 
internal products.

Kind of makes sense. It requires encryption products to implement
their own account/password store and would seem to prohibit tie-in
to single/same sign on systems. I wonder how many users use the
same password though.

It would also seem to prohibit a certificate based
authentication system that makes cert credentials available
to a user upon login.

Kind of like going back to basic separation of duty

So neither of these absolutely recommends against MS encryption, but there are some gotchas. Plus, since Bitlocker needs 
Vista and specific hardware, we've decided to do a third party approach to be more inclusive.

Thanks for your comments.


Steven Lovaas, MSIA, CISSP
Network Security Manager
Academic Computing & Network Services
Colorado State University
Steven.Lovaas () ColoState EDU
-----Original Message-----
From: Gary Flynn [mailto:flynngn () JMU EDU]
Sent: Monday, March 05, 2007 10:22 AM
Subject: Re: [SECURITY] Laptop Encryption Software

Our sensitive data group just published a guideline requiring encryption for sensitive data.


We are looking for a stopgap encryption solution so we have a mechanism that people can use to comply with the 

We are recommending Windows EFS on Windows XP computers and a combination of EFS and Bitlocker on Vista computers for 
this purpose.

I was wondering why others were choosing commercial solutions over the native EFS and Bitlocker as the strategic 
solution for workstation encryption.

If you're using a commercial product, does it perform key escrow to a centralized server? Is it a standalone product or 
does it require existing infrastructure such as an Active Directory domain and/or Microsoft CA?

If you've purchased a commercial product for this purpose, would you be willing to send me the pricing you have 
obtained offline and the volume of licenses you had to purchase to get that price?

On a side note, what do you think of the ATA hard disk security feature ( i.e. hard disk password )? Although its not 
based on encryption, it looks to me to be a fairly strong protection mechanism short of someone able to read bare, 
disassembled disks.


Gary Flynn
Security Engineer
James Madison University

Gary Flynn
Security Engineer
James Madison University

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