Re: AES cipher suites

[daw@xxxxxxxxxxxxxxxxxxxxxx (David Wagner)]

David Black wrote:
>On behalf of the IP Storage (ips) folks who are depending on AES
>counter mode, I want to make a strong request for specification of
>*both* an AES-CBC suite and an AES-CTR suite.  IPS's use of AES-CTR
>is motivated by a desire to build high-speed hardware.  While AES-CTR
>is the "right thing" for that class of implementation, I'm reluctant
>to impose it on everyone who wants to use AES by not defining an
>AES-CBC suite.

Why do you need both?  What problem does AES-CBC solve that AES-CTR
doesn't?  It looks to me like AES-CTR is likely to be good enough for
everything that AES-CBC is good enough for -- but then, I'm not familiar
with ips.  What am I missing?