AES-GCM performance on SE05x

[Viktro0929]

I am testing the capabilities of the SE050 on an OM-SE050X development board, and I have a question about the speed of the AES-GCM operation. It seems that when running a one-shot AES-GCM encryption with AAD, followed by decryption, the process takes around 8 to 9 seconds, even with small inputs in one-shot mode

I found a similar thread here discussing the same issue:

https://community.nxp.com/t5/Secure-Authentication/Re-SE050E-aead-encryption/m-p/1694085#M1317

The response there indicated that this is indeed expected, since the GCM part is not hardware-accelerated.

My questions are:

• Can you please confirm whether this speed is normal, and whether there is any way to improve performance, or if software-based GCM will remain at this speed regardless?
• Regarding the SE051 (or SE052), do these chips provide hardware acceleration for GCM, or any improvements in the speed of this operation?

Thank you in advance!

[Kan_Li]

Hi @Viktro0929 ,

Was it AES GCM 128 or 256? What about the data/AAD/IV length? From the test cases we have run, 8 to 9 seconds is little longer, what is the host controller you are using? Please kindly clarify.

Have a great day,
Kan

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[Viktro0929]

I am using test vectors from Test Case 3 of the following document:
https://csrc.nist.rip/groups/ST/toolkit/BCM/documents/proposedmodes/gcm/gcm-revised-spec.pdf 

Configuration details:

• AES-GCM 128-bit (16-byte key length)

• Data length: 60 bytes

• AAD length: 20 bytes

• IV length: 12 bytes

My OM-SE050X is connected to an ATSAMV71Q21 via I²C running at 100 kHz.

I have attached a screenshot of a typical encryption. As shown, after the initial setup, the host sends the plaintext and AAD, and the SE subsequently requests 5 WTXs. The WTX time was calculated based on the ATR response and the WTX message itself (as described in UM11225.pdf).

In total, the encryption process (including setup) took just under 7 seconds, of which about 1 second was spent in setup.

Thank you!

Best regards,

Viktor