diff --git a/crypto/Makefile b/crypto/Makefile
index ca5d034b5..b6dbeeedb 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -7,9 +7,6 @@ ifneq ($(CLANG_VERSION),)
 $(if $(shell [ $(CLANG_VERSION_MAJOR) -ge 13 ] && echo "OK"), \
     $(eval CLANG_AT_LEAST_13 := true), \
     $(eval CLANG_AT_LEAST_13 := false))
-$(if $(shell [ $(CLANG_VERSION_MAJOR) -ge 15 ] && echo "OK"), \
-    $(eval CLANG_AT_LEAST_15 := true), \
-    $(eval CLANG_AT_LEAST_15 := false))
 endif
 
 ifeq ($(FUZZER),1)
@@ -73,12 +70,6 @@ ZKP_PATH = ../vendor/secp256k1-zkp
 # this is specific for 64-bit builds
 CFLAGS += -DSECP256K1_CONTEXT_SIZE=208
 
-# TODO remove this workaround once possible
-ifeq ($(CLANG_AT_LEAST_15),true)
-$(warning "warning: suppressing clang-15 `-Wstrict-prototypes` compiler warning for `zkp_context.c` as workaround")
-zkp_context.o: CFLAGS += -Wno-strict-prototypes
-endif
-
 VALGRIND ?= 1
 ifeq ($(VALGRIND),1)
 CFLAGS += -DVALGRIND
diff --git a/crypto/zkp_context.c b/crypto/zkp_context.c
index 6416b7868..964140f06 100644
--- a/crypto/zkp_context.c
+++ b/crypto/zkp_context.c
@@ -51,7 +51,7 @@ int secp256k1_context_writable_randomize(secp256k1_context *context_writable) {
 bool zkp_context_is_initialized(void) { return context != NULL; }
 
 // returns 0 on success
-int zkp_context_init() {
+int zkp_context_init(void) {
   assert(context == NULL);
 
   const unsigned int context_flags =
@@ -78,7 +78,7 @@ int zkp_context_init() {
   return 0;
 }
 
-void zkp_context_destroy() {
+void zkp_context_destroy(void) {
   assert(context != NULL);
 
   secp256k1_context_preallocated_destroy(context);
@@ -87,14 +87,14 @@ void zkp_context_destroy() {
   context = NULL;
 }
 
-const secp256k1_context *zkp_context_get_read_only() {
+const secp256k1_context *zkp_context_get_read_only(void) {
   assert(context != NULL);
 
   return context;
 }
 
 // returns NULL if context cannot be acquired
-secp256k1_context *zkp_context_acquire_writable() {
+secp256k1_context *zkp_context_acquire_writable(void) {
   assert(context != NULL);
 
   // We don't expect the context to be used by multiple threads
@@ -105,7 +105,7 @@ secp256k1_context *zkp_context_acquire_writable() {
   return context;
 }
 
-void zkp_context_release_writable() {
+void zkp_context_release_writable(void) {
   assert(context != NULL);
 
   atomic_flag_clear(&locked);