All,

"odp_crypto_operation" API definition for combined crypto operation 
(i.e cypher and _then_ auth operation on  non-NULL auth and non-NULL cypher 
with overlapped range) 
seems to be too generic.
Currently we are passing cypher offset, cypher len, auth offset
and auth len parameters to define the overlapped range.

Defining the overlapped region with "single byte granularity" will effect the 
performance in co-processor based
cryto instruction implementation like ARMV8 crypto extension. I am not sure 
about dedicated HW based crypto 
mechanism, Is dedicated HW cryto implementation supports any arbitrary offset 
for cypher _and then_ auth operation ?
So in this context, I am trying to understand any data plane use case which 
demands for following overlapped range

1) auth offset > cypher offset(i.e starts with ciphering bytes then 
authentication)
2) auth offset < cypher offset and ((auth offset - cypher offset) % 8 != 0)), 
i.e difference between aoffset to coffset is
not 8 byte aligned.
3) (auth offset + auth len) < (cypher offset + cypher len), i.e there are bytes 
needs to cyphered after authentication.

If there are not such use-case then its better to define 
authentication range(in dwords) relative to cypher range for combined crypto 
operation
to get best platform performance.

Any thoughts ?

Regards,
Jerin.

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