QUERY · ISSUE

Pico AES CCM Mode

openby radu022003opened 2023-07-29updated 2024-12-11

enhancement

I would like to have the possibility to perform encryption using the aes ccm mode on a raspberry pi pico w.
This encryption is required for BTHome project.
I have successfully compiled the micropython with user c module examples and an example for native module as mpy, but I would still need an example in order to create a .mpy module using mbedtls ccm.
Thanks in advance.

CANDIDATE · ISSUE

Cryptolib throws ValueError

closedby jakobzudrellopened 2024-06-01updated 2024-06-03

bug

Port, board and/or hardware

rp2

MicroPython version

MicroPython v1.22.2 on 2024-02-22; Raspberry Pi Pico W with RP2040
MicroPython v1.24.0-preview.11.g1705bc52a on 2024-06-01; Raspberry Pi Pico with RP2040

Reproduction

cipher = cryptolib.aes(ubinascii.unhexlify(key), 6, iv)

Expected behaviour

A working AES instance

Observed behaviour

Traceback (most recent call last):
  File "<stdin>", line 34, in <module>
  File "<stdin>", line 20, in main
ValueError: mode

Additional Information

No, I've provided everything above.

Code of Conduct

Yes, I agree

Assessment

S Sonnet · high

Both issues concern AES encryption on rp2/Raspberry Pi Pico, touching the cryptolib/extmod area. However, they address distinct problems: #12113 is a feature request for AES CCM mode via mbedtls (a mode not supported at all in cryptolib), while #15185 is a bug report about cryptolib.aes() rejecting mode=6 (CTR mode) with a ValueError. Resolving the CTR bug does not provide CCM support, and adding CCM via mbedtls does not fix the cryptolib mode validation bug. They share the AES/rp2 domain but neither resolves the other.

Suggested action

No action needed between these two issues. They can be cross-referenced for context (both about AES limitations on rp2), but should remain open independently: #12113 as a feature request for CCM mode, #15185 as a bug in cryptolib mode validation.