feat(hal): Add countermeasure for ECDSA generate signature

The ECDSA peripheral before ECO5 of esp32h2 does not perform the ECDSA
    sign operation in constant time. This allows an attacker to read the
    power signature of the ECDSA sign operation and then calculate the
    ECDSA key stored inside the eFuse. The commit adds a countermeasure
    for this attack. In this case the real ECDSA sign operation is
    masked under dummy ECDSA sign operations to hide its real power
    signature

components/hal/include/hal/ecdsa_hal.h

@@ -16,11 +16,23 @@
 #include <stdint.h>
 #include "hal/ecdsa_types.h"
 #include "soc/soc_caps.h"
+#include "sdkconfig.h"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if CONFIG_HAL_ECDSA_GEN_SIG_CM
+
+#define ECDSA_SIGN_MAX_DUMMY_OP_COUNT 0x7
+
+/* This value defines the maximum dummy operation count for the ECDSA signature countermeasure.
+   Higher the number, better the countermeasure's effectiveness against attacks.
+   At the same time higher number leads to slower performance.
+   After the countermeasure is enabled, hardware ECDSA signature operation
+   shall take time approximately equal to original time multiplied by this number.
+   If you observe that the reduced performance is affecting your use-case then you may try reducing this time to the minimum. */
+#endif /* CONFIG_HAL_ECDSA_GEN_SIG_CM */
 /*
  * ECDSA peripheral config structure
  */