As I mentioned in the last post, TechDoc Flash10716 does talk about cipher 
block chaining support on the CEX3 and I'm pretty sure that support is 
available when the CEX3 is installed on z10.  But I'm not so sure that the 
chaining support that is avaliable on the CPACF hardware on the z196/z114 was 
retrofitted to the z10.  So in fact it may not be available on your machine.  
Additional research is required.  Does the vendor product claim to support CFB 
mode on a z10?  Do they call out a specific microcode level?

As Rob Schramm points out, you can start ICSF even if you don't have crypto 
cards, but if the product does not use the APIs that wouldn't provide any 
benefit. It is possible the vendor product could query the configuration and 
provide software routines that use the most efficient resources available.  
That is, the logic could query the config and if the CFB support is not 
available in the hardware, it could invoke the ICSF APIs that would perform 
CFB.  And in your case, since the APIs aren't available it might fall back on 
it's own software routines that do provide CFB support.  If this is true, then 
starting ICSF might help.  And you would not need an exit to provide the CFB 
support.  (I would not 
advocate using an ICSF exit to support CFB.)

I'm also wondering if they are using System SSL APIs? Does the vendor product 
specifically say that they are using the native instructions that are available 
on the CPACF hardware?  System SSL is very efficient and will query the 
environment to determine how best to service the request and as described above 
will often provide software routines if the appropriate hardware support or if 
ICSF is not available.

It would be helpful to know which vendor product you are working with.  If 
you'd like to take this up offline, we can summarize the results for the list 
later.  Feel free to send me a note.

Greg Boyd
Mainframe Crypto
www.mainframecrypto.com

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