Todd Arnold wrote:
>The article you referenced seems to assume whole-disk encryption is always 
>implemented using software on your computer, since it says "the operating 
>system has the decryption key to access the disk".  That is not true, of 
>course, for self-encrypting disk drives (or tape drives) where the encryption 
>key never leaves the hardware device in unencrypted form.  As I recall, the 
>key is served to the mainframe disk drives using a secure process such that it 
>is never available in the clear.

Sure…but that doesn’t make it any better: there’s still zero SoD involved. 
“Transparent” is appealing because it means “Easy to implement”. Alas, it 
doesn’t mean “secure”. I don’t think that assumption matters any to the value 
of whole-disk encryption (which, btw, has two other very valuable use cases: in 
outsourced data centers, where it isolates your data better from the other 
outsourcing customers’ data; and when decommissioning hardware—no  more “How 
many DSEs should we do? or “Should we take the drives out back, shoot ‘em with 
a 12-gauge, and then drop ‘em in the ocean?”).

>Regardless, it is true that the #1 benefit of encrypted disk and tape drives 
>is the case where the device can be stolen.  For tape, the usual example is 
>that someone loses or steals a tape when it is going out of your facility for 
>off-site backup.  For disk, the biggest risk scenario is a laptop, which can 
>be stolen or lost.  Obviously, it's a lot less likely that someone is going to 
>walk out of your data center with a disk drive that was in use by your 
>mainframe.  I think whole-disk encryption has value in all cases, but it has 
>the most value for devices or media that can easily move around.

Yeah, as I say in presentations: When was the last time you left a DS-8000 at 
an airline gate? (Though it does bring to mind a fellow who, a decade or so 
ago, had been promised a free 3274, and asked on a list whether he’d be able to 
bring it home on the subway…)
--
…phsiii

Phil Smith III
Senior Architect & Product Manager, Mainframe & Enterprise
HP Security Voltage

[email protected]<mailto:[email protected]>
T 703-476-4511
M 703-568-6662
Hewlett-Packard Company
Herndon, VA


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