a)release any resources that it had allocated to store data encryption parameters for the I_T nexus associated with the SECURITY PROTOCOL OUT command and shall change the contents of all memory containing a key value associated with the data encryption parameters that are released; and

b)establish a unit attention condition . . ."

The statement "data encryption parameters" was referenced to 4.2.21.8 earlier in that clause so if we follow that reference we find that virtually all of the settings that a host can establish are included in the data encryption parameters including the key instance counter which is tied to locking. When both modes are set to DISABLED which is what has to be done to turn encryption off, then everything in the set of data encryption parameters is released so all of those values are gone. If the counter is gone along with all the other parameters I don't see how the parameters can possibly continue to be associated with that I_T nexus.

According to my notes we discussed at the last SSC-3 meeting that "LOCK" should also be included in the data encryption parameters but wasn't due to an oversight. If it had been then it would be clear that "LOCK" is gone when the encryption parameters are released.

I'm concerned that this behavior seems to be inconsistent with the introduction to 4.2.21.11 which discusses exactly the case of resources being released and the UA not detected and suggests that LOCK solves the issue.

If the intent is that LOCK persist when the rest of the parameters are released then I don't think the change is as simple as you suggest. I think that we would need to modify 4.2.21.6 to indicate that the key instance counter is not released with the rest of the parameters if LOCK is set to one, but instead is incremented. That way the test described in the section on locking where a changed key instance counter triggers the CHECK CONDITION will still work. We might also have to modify some text describing releasing resources when limited resources are exhausted to make it clear that parameters containing a LOCK bit set to one can't be released (I have some concerns with whether that can be required). There might also be other sections that talking about releasing parameters that would need examined.

This one looks to me like it's going to take a proposal to address.

Curtis Ballard
Hewlett Packard

From: owner-t10@t10.org [mailto:owner-t10@t10.org] On Behalf Of Kevin D Butt
Sent: 20 March 2008 21:48
To: t10@t10.org
Subject: SSC-3: Late Letter Ballot comment

I received communication from an ISV today related to Encryption mode locking (4.2.21.11). They were unable to determine if the locking applied when the data encryption parameters were set such that encryption/decryption is turned off. In a close reading this clause refers to "...locked to that set of data encryption parameters and key instance counter value until a hard reset condition occurs or another [SPOUT command is received]"

In 4.2.21.6 Managing keys within the physical device, where it describes when to release a set of data encryption parameters, there is no mention of turning off encryption. Therefore, the locking does apply to the saved set of encryption parameters even when encryption is turned off. This is indeed the desired behavior. However, it is not clear to the casual or novice standards reader that this is the case.

Proposed Solution (Editorial):
In 4.2.21.11, p2, add a new sentence after s1:
The LOCK bit in the Set Data Encryption page is set to one to lock the I_T nexus that issued the SECURITY PROTOCOL OUT command to the set of data encryption parameters established at the completion of the processing of the command. A set of data encryption parameters are established and locked even if the ENCRYPTION MODE is set to DISABLE and the DECRYPTION MODE is set to DISABLE.

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/