Hi,

I was tinkering with RSA encryption with TPM and I noticed something odd. The 
spec says that when TSS_ES_RSAESPKCSV15 encryption scheme is used then data to 
be encrypted need to be wrapped with TCG_BOUND_DATA structure, however if 
encryption scheme is set to TSS_ES_RSAESOAEP_SHA1_MGF1 them TCG_BOUND_DATA 
structure is not required and data is encrypted as is.

I noticed that this is not the case with trousers. It uses TCG_BOUND_DATA 
structure even when TSS_ES_RSAESOAEP_SHA1_MGF1 encryption scheme is specified. 
This is not a big issue if trousers is the only implementation used since it 
handles this transparently and the only way it may be noticeable to the user is 
shortening of the size of available data by 5 bytes in comparison to the spec. 
But that would be very rare case when someone will miss those bytes :-)

However, I'm working with the environment where trousers will not be the only 
TSS implementation and interoperability is the must. My use case is having 
several migratable keys for content encryption on machines with different OSes 
(Windows, OSX, Linux, *BSD) and I will need to encrypt something on Linux and 
decrypt it on Windows using windows TPM services and vice versa. I only have 
trousers implementation right now but I'm worried about potential problems in 
the future.

So, could someone confirm if TSS_ES_RSAESOAEP_SHA1_MGF1 is indeed non-compliant 
or I'm missing something?

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