Re: [P1619-3] OASIS EKMI Article in InformationWeek
> data needs to be encrypted and decrypted only by the resources that
actually use data - the applications - and not the resources that store or
transport it.
This is where we disagree. The application does not have control over what
happens to its data, when it is in transit or in storage. Of course, it can
encrypt each piece of the data at the best security known, each with a
different key, with a different random IV, but it is horribly ineffective.
The application needs to get/store a large number of keys in key servers;
the auxiliary data somewhere else and the encrypted data in yet another
place. MS observed that if a byte takes more than 20 instructions to
encrypt, users disable the crypto. Securely storing large amount of data
under your paradigm is not realistic, and it will not be viable for quite a
while.
If the application does faster crypto instead of the best possible, there
will be exploitable weaknesses in some cases. This is why the transport
layer has to be and is optimized to its threat model, and the storage
device to its threat model. Both work orders of magnitude faster than what
you suggest.
Also, under your paradigm data and key are bound together, forever. If you
loose your key, the privacy is lost, too. If, however, the encryption is
done at the disk drive, any authorized entity can change the key as often
as necessary, so they can mitigate the lost key problems (until the
attacker finds all data encrypted with the lost key). In this sense, your
security is also weaker.
Arshad Noor
<arshad.noor@STRO
NGAUTH.COM> To
No Phone Info P1619-3@xxxxxxxxxxxxxxxxx
Available cc
Subject
07/02/2008 07:25 Re: [P1619-3] OASIS EKMI Article in
PM InformationWeek
Please respond to
Arshad Noor
<arshad.noor@STRO
NGAUTH.COM>
Laszlo,
The reason I keep saying that there is no *long-term* reason for
encrypting data on the device (or even the wire) is because of
my belief in the paradigm that data needs to be encrypted and
decrypted only by the resources that actually use data - the
applications - and not the resources that store or transport it.
The primary reason we have so many problems with securing IT
infrastructure today, is because, for the last 20 years, we've
been focusing on securing the network as a proxy for securing
applications and data. This is because network device vendors
have sold IT the notion that protecting the perimeter was all
that was required, and you could leave all your computer hosts,
applications and data alone. Very seductive. Thousands of
companies bought into the vision and now look where we are:
- Those who have firewalls must, typically, have port 25 and
port 80 open to do business - and guess what? The attackers
use precisely those ports to compromise live systems;
- Applications are weak and insecure - many developers are still
trying to protect against x-site scripting and SQL-injection
attacks on the internet. And now - are you ready? - we have
XML-injection attacks already surfacing against the new breed
of SOA-based applications because the security paradigm I'm
talking about is still out of focus for most IT organizations;
And the industry is now getting ready to sell IT shops the same
bag of goods - that its OK to continue ignoring the application
and data - the stuff that really matters - as long as we secure
the media and the wire.
Application developers have gotten increasingly security-ignorant
while attackers are getting increasingly sophisticated (one attack
I read about even installs the attackers self-signed Root CA X509
certificate on the target's PC and then redirects them to a cloned
web-site of a financial institution with their own SSL certificate,
thereby eliminating any security warnings about unknown CAs or
sites while having the "lock" icon clearly ON! All this for a
phishing attack. Most developers do not even understand how SSL
works, let alone code something as sophisticated as this).
If companies want to be secure, they need to stop focusing on the
perimeter and devices and focus on the applications and data. This
is the only long-term viable strategy, IMO.
Once they've secured their applications and data, they can ignore
the transport and media layers. A POS application encrypts CCN in
the application, passes the ciphertext to the DB, which stores the
ciphertext as a blob in the table on the storage media. Neither
the wire, the DB nor the media care what the blob means; only the
authorized application with the decryption key does.
Securing an application isn't just about encrypting data. Its also
about authenticating the resource that's trying to access the data;
its about determining the authorization of the resource trying to
access the data and finally, its also about determining the integrity
of the data being accessed. An application needs to do all this.
With the right combination of digital signatures and encryption
all the threats you enumerate are addressed.
You should download StrongKey and see what I'm talking about;
everything I've described in this e-mail was implemented two years
ago. This is the paradigm application developers need to move to
if IT organizations want long-term security benefits at the lowest
TCO. Just imagine, if all the applications developed over the last
20 years had followed this paradigm, we wouldn't even need firewalls
today.
Arshad Noor
StrongAuth, Inc.
Laszlo Hars wrote:
> I understand that EKMI does not care where and how the keys are used. I
had
> issues with your other statements, like saying that there is no need for
> encryption in the device level (P1619.0-2).
>
> You seem to agree that encryption in the transport layer is very
different
> from encryption in storage. In the later case, you cannot change the key
> very often or use arbitrary IV's, without a large loss of storage
capacity,
> or the need of transferring a large amount of non-user data from a key
> server, slowing the disks down. The need of encryption in the storage
> devices remains for practical reasons: speed, capacity, security,
> complexity...
>
>> Once the payload has been encrypted, then you can ignore threats to that
> data at all other layers of the stack.
>
> This is putting your head in the sand. Such systems can still leak
valuable
> information: the equality of data blocks, the frequency of updates of
> certain records, the location of system files, database records... We
could
> face malleability issues: messages could be replayed, data mixed and
> matched, program data patched, documents falsified, etc. Our goal should
> not be just to satisfy certain vaguely formulated laws, but to provide
> (facilitate) comprehensive security.
>
>