sys/psa_crypto: add monocypher as ed25519 software backend

[mguetschow]

Contribution description

Monocypher offers an implementation of Ed25519 that is much faster than the c25519 implementation, at the cost of higher flash consumption: See Table 4 of https://arxiv.org/pdf/2106.05577

This PR adds monocypher as a PSA Crypto API backend and enables it as default software backend.

Testing procedure

make -C tests/sys/psa_crypto_eddsa all flash test should select monocypher as default on BOARD=native and complete successfully.

On a BOARD=nrf52840dk, we get the following numbers:

$ USEMODULE="psa_asymmetric_ecc_ed25519_custom_backend psa_asymmetric_ecc_ed25519_backend_c25519" make -C tests/sys/psa_crypto_eddsa BOARD=nrf52840dk flash test
...
   text    data     bss     dec     hex
  24052     176    5348   29576    7388
...
EdDSA took 4295262 us
All Done
[TEST PASSED]
$ make -C tests/sys/psa_crypto_eddsa BOARD=nrf52840dk flash test
...
   text    data     bss     dec     hex
  32648     176    5348   38172    951c
...
EdDSA took 73349 us
All Done
[TEST PASSED]

Issues/PRs references

Builds on and includes #21821

[riot-ci]

Murdock results

✔️ PASSED

7f85d3a sys/psa_crypto: add monocypher as ed25519 software backend

Success	Failures	Total	Runtime
10931	0	10931	13m:32s

Artifacts

• Documentation preview

[mguetschow]

Rebased this on master after merge of #21821

[crasbe]

at the cost of higher flash consumption

Murdock agrees 👀

diff --git a/tests/sys/psa_crypto/Makefile.ci b/tests/sys/psa_crypto/Makefile.ci
index 5c1a01c4f4..dfd176a483 100644
--- a/tests/sys/psa_crypto/Makefile.ci
+++ b/tests/sys/psa_crypto/Makefile.ci
@@ -1,14 +1,7 @@
 BOARD_INSUFFICIENT_MEMORY := \
-    arduino-duemilanove \
-    arduino-leonardo \
-    arduino-mega2560 \
-    arduino-nano \
-    arduino-uno \
-    atmega328p \
-    atmega328p-xplained-mini \
-    atmega8 \
     bluepill-stm32f030c8 \
     i-nucleo-lrwan1 \
+    nucleo-c031c6 \
     nucleo-f030r8 \
     nucleo-f031k6 \
     nucleo-f042k6 \
@@ -19,6 +12,7 @@ BOARD_INSUFFICIENT_MEMORY := \
     slstk3400a \
     stk3200 \
     stm32c0116-dk \
+    stm32c0316-dk \
     stm32f030f4-demo \
     stm32f0discovery \
     stm32g0316-disco \

[mguetschow]

Murdock agrees 👀

Kind of - apparently monocypher is also 32-bit only? Anyways, I'll probably need such an update for tests/sys/psa_crypto_eddsa as well :)

[crasbe]

On it 🫡

[crasbe]

There you go:

diff --git a/tests/sys/psa_crypto_eddsa/Makefile.ci b/tests/sys/psa_crypto_eddsa/Makefile.ci
index 6a2fca3caf..4e4f6862b6 100644
--- a/tests/sys/psa_crypto_eddsa/Makefile.ci
+++ b/tests/sys/psa_crypto_eddsa/Makefile.ci
@@ -1,14 +1,14 @@
 BOARD_INSUFFICIENT_MEMORY := \
-    arduino-duemilanove \
-    arduino-leonardo \
-    arduino-nano \
-    arduino-uno \
-    atmega328p \
-    atmega328p-xplained-mini \
-    atmega8 \
+    nucleo-c031c6 \
     nucleo-f031k6 \
+    nucleo-f042k6 \
     nucleo-l011k4 \
+    nucleo-l031k6 \
     samd10-xmini \
     stk3200 \
+    stm32c0116-dk \
+    stm32c0316-dk \
     stm32f030f4-demo \
+    stm32g0316-disco \
+    weact-g030f6 \
     #

[mguetschow]

Thanks 🤗 Applied, force-pushed and queued to merge again :)