diff --git a/secp256k1zkp/depend/secp256k1-zkp/src/ecmult_gen_impl.h b/secp256k1zkp/depend/secp256k1-zkp/src/ecmult_gen_impl.h
index b63c4d866..c1e902423 100644
--- a/secp256k1zkp/depend/secp256k1-zkp/src/ecmult_gen_impl.h
+++ b/secp256k1zkp/depend/secp256k1-zkp/src/ecmult_gen_impl.h
@@ -14,6 +14,9 @@
 #ifdef USE_ECMULT_STATIC_PRECOMPUTATION
 #include "ecmult_static_context.h"
 #endif
+
+#include <string.h>
+
 static void secp256k1_ecmult_gen_context_init(secp256k1_ecmult_gen_context *ctx) {
     ctx->prec = NULL;
 }
diff --git a/secp256k1zkp/depend/secp256k1-zkp/src/ecmult_impl.h b/secp256k1zkp/depend/secp256k1-zkp/src/ecmult_impl.h
index e6e5f4718..81ae08e10 100644
--- a/secp256k1zkp/depend/secp256k1-zkp/src/ecmult_impl.h
+++ b/secp256k1zkp/depend/secp256k1-zkp/src/ecmult_impl.h
@@ -11,6 +11,8 @@
 #include "scalar.h"
 #include "ecmult.h"
 
+#include <string.h>
+
 /* optimal for 128-bit and 256-bit exponents. */
 #define WINDOW_A 5