Is it possible to migrate the algorithm to ARM STM32L4R5 Nucleo-l44 board with STM32CubeIDE?

[dingchaojie]

I have successfuly build and run the algorithm on Ubuntu, I'm wondering if the algorithm support ARM STM32L4R5 Nucleo-l44 board or can be easily compiled with STM32CubeIDE?

[real-or-random]

Our C code should build fine for any 32-bit platform. I don't know about this specific IDE but it seems to be based on gcc, which should be able to compile our code.

Note: We also have experimental ARM32 assembly code. Pass -DSECP256K1_ASM=arm32 -DSECP256K1_EXPERIMENTAL=ON to cmake, or --with-asm=arm32 --enable-experimental to ./configure to enable it. But try building without assembly first. This should be simpler.

[dingchaojie]

Yes, I also belive the algorithm can be migrate to STM32L4R5 Nucleo-l44 board, since I have migrated 2 ECC algorithms to the board
(https://github.com/kmackay/micro-ecc and https://github.com/orlp/ed25519)

I just confused by the code dependency, when I wrote my Makefie to try to understand the relationship on Linux(LinuxMint)
(Note: 1st step is write my Makefile to compile and run on Linux, if successful, then migrate the code used by the Makefile to STM32L4R5 Nucleo-l44 board)

jack@LinuxMint:~/fcb/bitcoin-core/secp256k1/examples$ cat Makefile 
ALL:
	gcc -o test_ecdsa.out ecdsa.c ../src/secp256k1.c ../src/precomputed_ecmult.c ../src/precomputed_ecmult_gen.c  -I../include -I../src 
	gcc -o test_ecdh.out ecdh.c ../src/secp256k1.c ../src/precomputed_ecmult.c ../src/precomputed_ecmult_gen.c  -I../include -I../src -I../src/modules/ecdh 

clean:
	rm *.out
jack@LinuxMint:~/fcb/bitcoin-core/secp256k1/examples$ make
gcc -o test_ecdsa.out ecdsa.c ../src/secp256k1.c ../src/precomputed_ecmult.c ../src/precomputed_ecmult_gen.c  -I../include -I../src 
gcc -o test_ecdh.out ecdh.c ../src/secp256k1.c ../src/precomputed_ecmult.c ../src/precomputed_ecmult_gen.c  -I../include -I../src -I../src/modules/ecdh 
/usr/bin/ld: /tmp/cc8yRnGF.o: in function `main':
ecdh.c:(.text+0x450): undefined reference to `secp256k1_ecdh'
/usr/bin/ld: ecdh.c:(.text+0x4b7): undefined reference to `secp256k1_ecdh'
collect2: error: ld returned 1 exit status
make: *** [Makefile:3: ALL] Error 1
jack@LinuxMint:~/fcb/bitcoin-core/secp256k1/examples$ 

As showd above, the ECDSA testcase compiled successfully(also can run successfully), but ECDH testcase failed, I tried to modify source files but, the code relationship confused me. Especiall include "../../../src/xxx.h", usually I prefer include "xxx.h" and add include directory to makefile.
If possible could you please update my Makefile to compile ECDH testcase successful on Linux, thank you.

[real-or-random]

Add -DENABLE_MODULE_ECDH:

gcc -o test_ecdh.out ecdh.c ../src/secp256k1.c ../src/precomputed_ecmult.c ../src/precomputed_ecmult_gen.c  -I../include -I../src -I../src/modules/ecdh -DENABLE_MODULE_ECDH

But please, while building manually is possible and we try to make it not too hard, we ship with two common build systems, autoconf+automake and CMake. See the README file. Pick either, and it will generate a working Makefile for you automatically.

[dingchaojie]

Thanks for your quickly reply. Yes, it works. But I also met issues while compile the reset testcases like musig.c, schnorr.c, ellswift.c. I tried with macor -DENABLE_MODULE_MUSIG for musig.c but with errors, for example.

If possible, could you please provide me the whole Makefile to compile testcases in the examples folder?

[real-or-random]

The musig module depends on the schnorrsig module, which depends on extrakeys module. Please see this for all module flags and dependencies:

secp256k1/configure.ac

Lines 398 to 430 in e7f7083

	# Processing must be done in a reverse topological sorting of the dependency graph
	# (dependent module first).
	if test x"$enable_module_ellswift" = x"yes"; then
	SECP_CONFIG_DEFINES="$SECP_CONFIG_DEFINES -DENABLE_MODULE_ELLSWIFT=1"
	fi
	if test x"$enable_module_musig" = x"yes"; then
	if test x"$enable_module_schnorrsig" = x"no"; then
	AC_MSG_ERROR([Module dependency error: You have disabled the schnorrsig module explicitly, but it is required by the musig module.])
	fi
	enable_module_schnorrsig=yes
	SECP_CONFIG_DEFINES="$SECP_CONFIG_DEFINES -DENABLE_MODULE_MUSIG=1"
	fi
	if test x"$enable_module_schnorrsig" = x"yes"; then
	if test x"$enable_module_extrakeys" = x"no"; then
	AC_MSG_ERROR([Module dependency error: You have disabled the extrakeys module explicitly, but it is required by the schnorrsig module.])
	fi
	enable_module_extrakeys=yes
	SECP_CONFIG_DEFINES="$SECP_CONFIG_DEFINES -DENABLE_MODULE_SCHNORRSIG=1"
	fi
	if test x"$enable_module_extrakeys" = x"yes"; then
	SECP_CONFIG_DEFINES="$SECP_CONFIG_DEFINES -DENABLE_MODULE_EXTRAKEYS=1"
	fi
	if test x"$enable_module_recovery" = x"yes"; then
	SECP_CONFIG_DEFINES="$SECP_CONFIG_DEFINES -DENABLE_MODULE_RECOVERY=1"
	fi
	if test x"$enable_module_ecdh" = x"yes"; then
	SECP_CONFIG_DEFINES="$SECP_CONFIG_DEFINES -DENABLE_MODULE_ECDH=1"
	fi

Or use run ./autogen.sh and ./configure --enable-module-musig in the root directory of the repository to generate a Makefile.

[dingchaojie]

Thanks for your guide, Finally all the testcases can be built and run succeffully. I listed my Makefile(in directory secp256k1/examples) in case other guys also need it

ALL:
	gcc -o test_ecdsa.out ecdsa.c ../src/secp256k1.c ../src/precomputed_ecmult.c ../src/precomputed_ecmult_gen.c  -I../include -I../src 
	gcc -o test_ecdh.out ecdh.c ../src/secp256k1.c ../src/precomputed_ecmult.c ../src/precomputed_ecmult_gen.c  -I../include -I../src -I../src/modules/ecdh -DENABLE_MODULE_ECDH 
	gcc -o test_musig.out musig.c ../src/secp256k1.c ../src/precomputed_ecmult.c ../src/precomputed_ecmult_gen.c  -I../include -I../src -I../src/modules/musig -DENABLE_MODULE_MUSIG -DENABLE_MODULE_EXTRAKEYS -DENABLE_MODULE_SCHNORRSIG  
	gcc -o test_ellswift.out ellswift.c ../src/secp256k1.c ../src/precomputed_ecmult.c ../src/precomputed_ecmult_gen.c  -I../include -I../src -I../src/modules/ellswift -DENABLE_MODULE_ELLSWIFT
	gcc -o test_schnorr.out schnorr.c ../src/secp256k1.c ../src/precomputed_ecmult.c ../src/precomputed_ecmult_gen.c  -I../include -I../src -DENABLE_MODULE_EXTRAKEYS -DENABLE_MODULE_SCHNORRSIG 

clean:
	rm *.out

[real-or-random]

One more note:

You can also tweak performance parameters.

Smaller values mean the binary will be significantly smaller. Larger values may or may not provide better running time. The default values are optimized for a desktop machine, so you may want to tweak them on an embedded system:

• Pick one of these three parameter pairs (used computations involving a secret key. e.g., key generation and signing): -DCOMB_BLOCKS=2 -DCOMB_TEETH=5 or -DCOMB_BLOCKS=11 -DCOMB_TEETH=6 or -DCOMB_BLOCKS=11 -DCOMB_TEETH=6. The last one is the default.
• Pick 2 <= w <= 15 (used for computations without a secret key, e.g., verification) and set -DECMULT_WINDOW_SIZE=w. The default is 15. My best guess is that 4 is a reasonable value for your platform.

edit: And you also want to pass -O2, of course.

[dingchaojie]

Just a tiny issue that massive(224) compile warnings, I have to add compile option "-Wno-unused-function" to suppress them, that's okay, but one waring is special as showed below, how to fix this one?

arm-none-eabi-gcc "../Core/Algorithm/ed25519/ed25519_intf.c" -mcpu=cortex-m4 -std=gnu11 -g3 -DDEBUG -DUSE_HAL_DRIVER -DSTM32L4R5xx -DENABLE_MODULE_ECDH -DENABLE_MODULE_ELLSWIFT -DENABLE_MODULE_MUSIG -DENABLE_MODULE_EXTRAKEYS -DENABLE_MODULE_SCHNORRSIG -DSECP256K1_ASM=arm32 -DSECP256K1_EXPERIMENTAL=ON -DECMULT_WINDOW_SIZE=4 -c -I../Core/Inc -I../Core/Algorithm -I../Core/Algorithm/micro-ecc -I../Core/Algorithm/secp256k1/include -I../Core/Algorithm/secp256k1/src -I../Core/Utility -I../Drivers/STM32L4xx_HAL_Driver/Inc -I../Drivers/STM32L4xx_HAL_Driver/Inc/Legacy -I../Drivers/CMSIS/Device/ST/STM32L4xx/Include -I../Drivers/CMSIS/Include -O2 -ffunction-sections -fdata-sections -Wall -Wno-unused-function -fstack-usage -fcyclomatic-complexity -MMD -MP -MF"Core/Algorithm/ed25519/ed25519_intf.d" -MT"Core/Algorithm/ed25519/ed25519_intf.o" --specs=nano.specs -mfpu=fpv4-sp-d16 -mfloat-abi=hard -mthumb -o "Core/Algorithm/ed25519/ed25519_intf.o"
../Core/Algorithm/secp256k1/secp256k1_check.c: In function 'secp256k1_check_ecdh':
../Core/Algorithm/secp256k1/secp256k1_check.c:469:18: warning: implicit declaration of function 'secp256k1_ecdh'; did you mean 'secp256k1_check_ecdh'? [-Wimplicit-function-declaration]
  469 |     return_val = secp256k1_ecdh(ctx, shared_secret1, &pubkey2, seckey1, NULL, NULL);
      |                  ^~~~~~~~~~~~~~
      |                  secp256k1_check_ecdh

compile_warning_details_all.txt