[chopstx] Add support for Blue Pill Plus board

Frédéric SUEL frederic.suel at free.fr
Fri Mar 14 17:42:52 CET 2025


Hello,

A lot of thanks for your work.

See my observations /infra/. I hope it can help you.

Best regards

Le 13/03/2025 à 19:52, Alexandre Esse a écrit :
> Hello Frédéric,
>
> Great, I didn't see you already did some integration developments on 
> this board, I just joined the mailing list and didn't look extensively 
> into the history. For now I only pushed the chopstx part but indeed, 
> gnuk itself should also be updated.
>
> I also have the STM32F103CBT6 version of the board. (marked as v1.1 on 
> the PCB: not sure what it means: I opened an Issue on github and send 
> an email to WeAct support to get some info: 
> https://github.com/WeActStudio/BluePill-Plus/issues/19)
You can find the difference between V1.0 et V1.1 here : 
https://github.com/WeActStudio/WeActStudio.BluePill-Plus-CH32/tree/master/HDK 
It's for CH32 processor but the design of the boards are all the same.
>
> I have been testing both on the 1.2.20 branch and 2.2. But I guess I 
> will stay on v2.2 for the rest of my tests.
>
> Here are the remaining tweaks I did on v2.2 
> (de9652726b1ce52b21e939c6989dda0268b5c640)of gnuk to make it work:
>
> diff --git a/src/configure b/src/configure
> index 1188a72..4ff7d1a 100755
> --- a/src/configure
> +++ b/src/configure
> @@ -130,6 +130,7 @@ Configuration:
>                            ST_NUCLEO_F103
>                            NITROKEY_START
>                            BLUE_PILL
> +                          BLUE_PILL_PLUS
>                            STM8S_DISCOVERY
>                            CQ_STARM
>                            STM32_PRIMER2
> @@ -164,7 +165,7 @@ MEMORY_SIZE=20
>
>  # Settings for TARGET
>  case $target in
> -BLUE_PILL|STM8S_DISCOVERY)
> +BLUE_PILL|BLUE_PILL_PLUS|STM8S_DISCOVERY)
>    # It's 64KB version of STM32F103, but actually has 128KB
>    flash_override="-DSTM32F103_OVERRIDE_FLASH_SIZE_KB=128"
>    ;;
>
There is STM32F103C6T6 (64K)  and CBT6 (128K), so i think your add 
relative to : # setting to target, is not necessary for CBT6 processor 
which have 128K memory. That's why i suggested to have multiple 
definition board to take care of different processor (arm and riscv) and 
different amount of memory
> I haven't been testing "on-the-token" key generation. I only 
> transferred to it from a host PC. I always had KDF-DO activated.
> The main issue I get is when I try to "reset" the token, it simply 
> doesn't work but I haven't been investigating it.
> Also some PIN management's actions seem shaky (but there is a 
> possibility that this is due to my lack of experience on gnuk tokens too).
> So for now, I tested the key with this kind of secret keys I get with 
> 'gpg --list-secret-keys':
> sec>  ed25519 2025-03-13 [SC]
>       XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
>       Card serial no. = FFFF 00000000
> uid           [ultimate] Tmp Tmp <tmp at tmp.tmp>
> ssb>  cv25519 2025-03-13 [E]
> ssb>  ed25519 2025-03-13 [A]
> I managed to sign, decrypt data and authenticate through ssh sessions 
> with it.
> PB2 as LED is working and PA0 as ACK button is also working fine, I 
> haven't seen any issue for these use-case in a week.

About ack button, it is on PA0 and PA0 is used for it's ADC function and 
entropy generation, so i think you have to modifiy 
/gnuk/chopstx/contrib/adc-stm32ff103.c in order to use an other pin for 
ADC than PA0

Entropy generation graph is explain on Niibe site here : 
https://www.gniibe.org/memo/development/gnuk/rng/neug.html

You can see that PA0 and PA1 are used for their ADC. It's also indicate 
for example in board-fst-01-00.h file

  * PA0  - input with pull-up.  AN0
  * PA1  - input with pull-up.  AN1

For Blue-Pill-Plus, button is connect to 3.3V 
(https://github.com/WeActStudio/BluePill-Plus/blob/master/HDK/BluePillPlus_V10_SchDoc.pdf) 
so i think you configure PA0 as input pull-down. I think all this change 
can interfere with good entropy generation. I see different cases of 
board in /gnuk/chopstx/contrib/adc-stm32ff103.c which seem to use 
different ADC pins but i don't really understand how. It's for that, i 
didn't take care of ackbutton to day.

---------------------------------------------------------------

In your board file, you indicate id board : 0x49403d56. In mine, i 
indicate 0x1ba01477. I get this id with stlink program as core id. Can 
your tell me how you get your board id ?

Frédéric SUEL

>
> Regards,
> Alexandre
>
>
>
> On Fri, 7 Mar 2025 at 10:00, Frédéric SUEL <frederic.suel at free.fr> wrote:
>
>     Ref : Post on the gnuk list : Frédéric SUEL frederic.suel at
>     free.fr <http://free.fr> Mon Feb 17 11:13:25 CET 2025
>
>     Hi,
>
>     Thank you for your interest for this board.
>
>     When i asked help about this board, i proposed a file
>     board-blue-pill-plus-cb.h because this board exist with 4 arm
>     processor and two riscv processors. I indicated cd because there
>     is STM32F103C8T6 (64k)  and CBT6 (128k). To take care of 64K
>     version, you have to add code in /gnuk/src/.configure. (see my post)
>
>     For my blue-pilll-board stm32F103CB, i have #define BOARD_ID   
>     0x1ba01477 (see my post). Perhaps your board is a STM32F103C6T6
>     board, i don't know why IDs are different
>
>     For instance, i doesn't take care of ackbutton because there is a
>     supplementary problem as PA0 is used for it's ADC and for entropy
>     generation. I think you have to modify
>     /gnuk/chopstx/contrib/adc-stm32ff103.c but i doesn't know how.
>
>     ----
>
>     So i just created /gnuk/board/board-blue-pill-plus-cb.h, modified
>     /gnuk/src/.configure to add definition of BLUE-PILL-PLLUS-CB
>     and/**/chopstx/mcu/sys-stm31f103.h for my first tests and doesn't
>     take care of ackbutton on PA0
>
>     I get :
>
>     -- works fine with curve25519 : generation on the board and import
>     on the board.
>
>     -- impossibility to generate secp256k1 on the board even with
>     KDF-DO activate as Niibe suggested (msg : used conditions not
>     satisfied)
>
>     -- impossibility to generate X448 on the board even with Niibe
>     patch (msg : board error)
>
>     -- impossibility to import X448 on the board. It seems to work but
>     only encrypt key is on the board and works. The other keys are
>     marked as # .  I get with gpg --list-secret-keys
>
>     sec#  ed448/0xAA988F88C70C3DEE 2025-02-23 [SC] [expire : 2075-02-11]
>
>     Empreinte de la clef = AA988 F88C7 0C3DE E74BE DFF48 D127D 4BA4E
>     CAEB3 685B3 575E7
>
>     uid                  [  ultime ] tmp
>
>     ssb>  cv448/0x406CC6562774BC84 2025-02-23 [E] [expire : 2075-02-11]
>
>     ssb#  ed448/0x02BB1F8E7A2B268A 2025-02-23 [A] [expire : 2075-02-11]
>
>     ----
>
>     Can you precise what's work with your board ?
>
>     Best regards
>
>
>
>     Le 06/03/2025 à 23:47, Alexandre Esse a écrit :
>>     Hello,
>>
>>     Here is a short message to notify the mailing list that I
>>     proposed a merge request on chopstx:
>>     https://salsa.debian.org/gnuk-team/chopstx/chopstx/-/merge_requests/1
>>
>>     This is the first step to add gnuk support for Blue Pill Plus
>>     boards <https://github.com/WeActStudio/BluePill-Plus/>.
>>
>>     Not sure if this is the way to contribute: looking forward to
>>     your feedback.
>>
>>     Regards,
>>     Alexandre
>>
>>     _______________________________________________
>>     Gnuk-users mailing list
>>     Gnuk-users at gnupg.org
>>     https://lists.gnupg.org/mailman/listinfo/gnuk-users
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.gnupg.org/pipermail/gnuk-users/attachments/20250314/b34e3d9f/attachment.html>


More information about the Gnuk-users mailing list