Roger,

I am trying to solidify what should be done to respond to this letter ballot comment.  I am not sure if you responded to my comments below.  Could you take a look at them and provide me your thoughts?  I will then create a proposal so we can review the specifics.

Thanks,

Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-2869 / 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt@us.ibm.com
http://www-03.ibm.com/servers/storage/


From: Kevin D Butt/Tucson/IBM
To: "Paul Suhler" <Paul.Suhler@Quantum.Com>
Cc: owner-t10@t10.org, t10@t10.org
Date: 06/20/2008 04:41 PM
Subject: RE: SSC-3: Discussion related to Letter Ballot SYM-019-a



Thanks Paul. I did not intend to limit the use case to the one I mentioned.  It is intended only as on example of one use case.  There certainly are more as you have pointed out.

Thanks,

Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-2869 / 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt@us.ibm.com
http://www-03.ibm.com/servers/storage/



"Paul Suhler" <Paul.Suhler@Quantum.Com>
Sent by: owner-t10@t10.org

06/20/2008 03:38 PM

To
<t10@t10.org>
cc
Subject
RE: SSC-3: Discussion related to Letter Ballot SYM-019-a





I believe that there was another use case in which old tapes were copied onto newer tapes to avoid wear becoming so bad that error rates would go up too much.  Keyless copy was seen as a way of improving the security of this.
 
Thanks,
 
Paul
___________________________________
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From: owner-t10@t10.org [mailto:owner-t10@t10.org] On Behalf Of Kevin D Butt
Sent: Friday, June 20, 2008 11:14 AM
To: Roger Cummings
Cc: t10@t10.org
Subject: RE: SSC-3: Discussion related to Letter Ballot SYM-019-a


Roger,

The group forced me to create the KCSLU and KCDLU terms in order to describe the feature.  In describing what one device is doing, I could only talk about RAW because to read you need to be in RAW mode and for the other when writing I could only talk about EXTERNAL because you need to be in EXTERNAL to write.  So I had to narrow  the discussion depending on whether I was talking about reading or writing. The keyless copy section is intended to describe how to use the RAW and EXTERNAL modes.  I personally don't care what terms are used.  Let me describe the intent then we can understand what needs to be described.  Hopefully this will help us describe it clearly.

The intent is that a system can use the keyless copy capability to copy data from one tape to another without requiring an encryption/decryption key.  The use case would be a data recovery lab.  The lab are the experts on getting the data off the tape but the user doesn't want to expose the data.  Hence the need to copy the data without having the decryption key.  I envision that if a device supports RAW it will also support EXTERNAL.  I really don't see a use case where support for one but not the other makes sense.  I would have no problem with stating that if RAW is supported EXTERNAL shall be supported and vice-versa.

Thanks,

Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-2869 / 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt@us.ibm.com
http://www-03.ibm.com/servers/storage/

"Roger Cummings" <roger_cummings@symantec.com>

06/20/2008 08:04 AM


To
Kevin D Butt/Tucson/IBM@IBMUS
cc
<t10@t10.org>
Subject
RE: SSC-3: Discussion related to Letter Ballot SYM-019-a







Kevin,
 
I'm not sure that I can accept your simplification that this collapses to which settings of "ENCRYPTION MODE" and "DECRYPTION MODE" fields are supported. The issue I'm having relates to the second paragraph on page 55 (PDF page 74) of SSC-3 Rev 4a, which seems to imply that for some encryption algorithms it's necessary for the KCSLU to support both EXTERNAL & RAW modes, but for others RAW support is sufficient. Is the converse of this true i.e. some LUs that support RAW mode will NOT be able to act as KCSLUs?
 
I do agree that this would be a useful simplification if we can resolve the above point, which I freely admit may be a misunderstanding on my point. And being able to read the capability of an LU wrt encryption modes in advance would definitely be a useful thing for our apps. But if we can make that simplification then I'd recommend that we delete the terms KCSLU & KCDLU in their entirety as all they mean is "an LU that supports RAW mode" and "an LU that supports EXTERNAL mode" respectively.
 
Regards,
 
 
 
 
Roger
 
P.S. And I haven't forgotten that I have an AI related to SYM-019-b, and I hope to have something on that subject ready for Anchorage.

From: owner-t10@t10.org [mailto:owner-t10@t10.org] On Behalf Of Kevin D Butt
Sent: Thursday, June 19, 2008 3:32 PM
To: t10@t10.org
Subject: SSC-3: Discussion related to Letter Ballot SYM-019-a


SYM-019-a:
The 4.2.21.5 Keyless copy section should identify How an application client determines that a Logical Unit has the capability to act as a KCSLU or a KCDLU

There is no bit anywhere that indicates the support for acting as a KCSLU or KCDLU.  In reality, it is if the LU supports the EXTERNAL encryption mode or the RAW decryption mode.  So the request here should be reworded to say how does an application client determine which settings of "ENCRYPTION MODE" and "DECRYPTION MODE" fields are supported.

Looking at the section describing each of these fields, there is no text describing a CC returned for RAW or EXTERNAL if they are not supported.  The standard is silent.  This is also the case for DISABLE.  Obviously the standard does not explicitly indicate anywhere that these modes are optional.

What should we do?
Option 1: Add text under the description of these fields stating that if EXTERNAL or RAW mode is selected and it is not supported then CC.  This would change the standard to explicitly state that these options are optional.
Option 2: Add text somewhere to mandate support for these modes.  I suspect this option is not desired.

I think that we must do either option 1 or option 2.  The standard needs to be clear if these are optional or not.

If we go done the path that these are explicitly stated as optional, then this letter ballot comment leads to the question, "How do we report support for different values in these two fields?"  This is not just a question of Keyless copy but also of MIXED decryption mode.  There is an implication that ENCRYPT and DECRYPT are supported as well as DISABLE.  I am not sure that is correct.  There could be a device that only supportes one or the other or some combinations.

Comments?

Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-2869 / 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt@us.ibm.com
http://www-03.ibm.com/servers/storage/
The information contained in this transmission may be confidential. Any disclosure, copying, or further distribution of confidential information is not permitted unless such privilege is explicitly granted in writing by Quantum Corporation. Furthermore, Quantum Corporation is not responsible for the proper and complete transmission of the substance of this communication or for any delay in its receipt.