diff --git a/library/pk_internal.h b/library/pk_internal.h
index ae32955..ece2f82 100644
--- a/library/pk_internal.h
+++ b/library/pk_internal.h
@@ -119,6 +119,16 @@
 #if defined(MBEDTLS_ECP_HAVE_CURVE25519) || defined(MBEDTLS_ECP_HAVE_CURVE448)
 #define MBEDTLS_PK_HAVE_RFC8410_CURVES
 #endif /* MBEDTLS_ECP_HAVE_CURVE25519 || MBEDTLS_ECP_DP_CURVE448 */
+
+#define MBEDTLS_PK_IS_RFC8410_GROUP_ID(id)  \
+    ((id == MBEDTLS_ECP_DP_CURVE25519) || (id == MBEDTLS_ECP_DP_CURVE448))
+
+static inline int mbedtls_pk_is_rfc8410(const mbedtls_pk_context *pk)
+{
+    mbedtls_ecp_group_id id = mbedtls_pk_get_group_id(pk);
+
+    return MBEDTLS_PK_IS_RFC8410_GROUP_ID(id);
+}
 #endif /* MBEDTLS_PK_HAVE_ECC_KEYS */
 
 /* Helper for (deterministic) ECDSA */
diff --git a/library/pkparse.c b/library/pkparse.c
index 608c854..0b5de8d 100644
--- a/library/pkparse.c
+++ b/library/pkparse.c
@@ -863,12 +863,6 @@
     return 0;
 }
 
-/* Helper for Montgomery curves */
-#if defined(MBEDTLS_PK_HAVE_RFC8410_CURVES)
-#define MBEDTLS_PK_IS_RFC8410_GROUP_ID(id)  \
-    ((id == MBEDTLS_ECP_DP_CURVE25519) || (id == MBEDTLS_ECP_DP_CURVE448))
-#endif /* MBEDTLS_PK_HAVE_RFC8410_CURVES */
-
 /*
  *  SubjectPublicKeyInfo  ::=  SEQUENCE  {
  *       algorithm            AlgorithmIdentifier,
diff --git a/library/pkwrite.c b/library/pkwrite.c
index 7a9cfed..468df14 100644
--- a/library/pkwrite.c
+++ b/library/pkwrite.c
@@ -366,23 +366,6 @@
 }
 
 #if defined(MBEDTLS_PK_HAVE_RFC8410_CURVES)
-static inline int mbedtls_pk_is_rfc8410(const mbedtls_pk_context *pk)
-{
-    mbedtls_ecp_group_id id = mbedtls_pk_get_group_id(pk);
-
-#if defined(MBEDTLS_ECP_HAVE_CURVE25519)
-    if (id == MBEDTLS_ECP_DP_CURVE25519) {
-        return 1;
-    }
-#endif
-#if defined(MBEDTLS_ECP_HAVE_CURVE448)
-    if (id == MBEDTLS_ECP_DP_CURVE448) {
-        return 1;
-    }
-#endif
-    return 0;
-}
-
 /*
  * RFC8410 section 7
  *