AM3352: HS Device Security Authentication Process - PQC with Software

Hi Hong,

Thank you for your support.

Previously you said that on previous thread,

Here’re some options for your customer to explore:
- adding an external TPM/SE device with a future PQC-protected firmware update mechanism.
- looking for the PQC lib which can be integrated into the user code base (i.e. bootloader)

AM3352: HS Device Security Authentication Process - Processors forum - Processors - TI E2E support forums

Customer is exploring to look for the PQC lib which can be integrated into the user code base right now.

Could you please elaborate ?

Best regards,

Kenley

Hi Kenley,
Let me add clarification on my last reply.

Hong Guan64 said:

AM335x HS onchip ROM supports only RSA based PKCS signature verification.
It is impossible to support PQC in AM335x HS device.

The user' bootloader needs to be signed with RSA key offline, and then authenticated by onchip ROM using RSA based PKCS signature verification in ontarget boot process. It is impossible to verify the user's bootloader with PQC.

1/. After the user's bootloader is verified and booted by AM335x onchip ROM with RSA based PKCS scheme,
- In theory, with AM335x SecDev package, it is possible to sign any data blob (i.e. PQC public key) with RSA key using IFT, and verify the signed data blob by calling ROM/PPA API for RSA based PKCS signature verifications by user's bootloader. This step verify the binary blob (i.e. PQC public key) by the user's bootloader...

2/. After the last step, user may explore how to add PQC support for next stage binary blob verifications, TPM/SE or PQC lib...
- user's bootloader can continue PQC based signature verifications using (TPM/SE, PQC lib...) with the verified PQC public key in the last step...

Best,
-Hong

Hi Hong,

Thank you for your support.

Let me clarify.

Do you mean PQC could be supported but by following the step you just mentioned, it is correct or not ?

And could you answer these questions please.

1. According to the AM3352 HS device specification, the public key certificate currently contains 256 bytes of public key. If customer replace this with approximately 3 Kbytes (public key for PQC), will it work?
Customer's expects Normal operation until the public key for PQC is verified and started.

→？

2. (if 1 is Yes) Customer would like to use an Image Formatting Tool (IFT) that supports PQC. Will it be available?

→？

3. (when 2 is No) If a PQC-compliant IFT is not provided, customer will need to make their own. Is it possible to make their own IFT?

→？

4. Software verification (PQC) may affect startup speed. One possible solution is to change to HW Validation (PQC).
Will there be a CPU that can verify PQC signatures directly on the CPU? Customer want a device that is compatible with the existing AM3352 HS device.

→？

Best regards,

Kenley

Hi Kenley,

Kenley said:

Do you mean PQC could be supported but by following the step you just mentioned, it is correct or not ?

The step 1/ in my last reply is feasible using AM335x SecDev package with AM335x ROM/PPA support, and the step 2/ will need to be explored by customer to have PQC support with TPM/SE or PQC lib...

Kenley said:

1. According to the AM3352 HS device specification, the public key certificate currently contains 256 bytes of public key. If customer replace this with approximately 3 Kbytes (public key for PQC), will it work?
Customer's expects Normal operation until the public key for PQC is verified and started.

No, it wouldn't work to replace RSA public key with the PQC key as PKC structure is fixed to support RSA key only.

Best,
-Hong

Hi Hong,

Thank you.

How about this question?

4. Software verification (PQC) may affect startup speed. One possible solution is to change to HW Validation (PQC).
Will there be a CPU that can verify PQC signatures directly on the CPU? Customer want a device that is compatible with the existing AM3352 HS device.

Thank you in advance,

Kenley

Hi Kenley,
TI is working on adding PQC support for the newer processor, but not AM335x HS compatible one.
Best,
-Hong