• From: Paris (France)
  • Registered: 2021-04-28
  • Posts: 12

Topic: Symmetric crypto on windows 10

Hello,

I'm trying to cipher using AES with any possible mode, and here is what I get :
For all modes except CFB, wolfTPM2_CreateAndLoadKey returns an error 713 ("Mode of operation not supported").
Not pleasant, but at least, standard.
(I think this is because of my Infineon ship that implements CFB only...)

For CFB, wolfTPM2_CreateAndLoadKey is successful, but then, wolfTPM2_EncryptDecrypt returns an error 0x80280400 which is not even a standard TPM code!
After a while, I found out that it is a pure windows code for "blocked command".

So, if I haven't missed anything, I can't do any symmetric ciphering...
I'm using a code very similar to the bench exemple here : https://github.com/wolfSSL/wolfTPM/blob … nch.c#L149.

Any idea ?
Thanks in advance!

Hadrien

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  • Registered: 2020-11-04
  • Posts: 16

Re: Symmetric crypto on windows 10

Hi Hadrien,

Typically, symmetric key operations are restricted on TPM due to export regulations(law).

However, you could still develop and test these operations using a TPM Simulator.

Please check out our documentation for how to develop using a TPM simulator - https://github.com/wolfSSL/wolfTPM/blob … s/SWTPM.md

Thanks,
Dimi

Dimi Tomov,
wolfSSL Engineer and Founder of TPM.dev

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  • From: Paris (France)
  • Registered: 2021-04-28
  • Posts: 12

Re: Symmetric crypto on windows 10

Thank you Dimi,
but, is there something more  in using a simulator than using my former software lib crypto ?

Hadrien

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  • Registered: 2020-11-04
  • Posts: 16

Re: Symmetric crypto on windows 10

Hi Hadrien,

The benefit of working with the TPM simulator is that the code you write using wolfTPM will be exactly the same when you switch to a physical, dedicated TPM chip on the real hardware.

Please let me know if you have more questions.

Thanks,
Dimi

Dimi Tomov,
wolfSSL Engineer and Founder of TPM.dev

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