diff --git a/lib/internal.h b/lib/internal.h
index c718bc95..0463004a 100644
--- a/lib/internal.h
+++ b/lib/internal.h
@@ -85,4 +85,6 @@ struct backend_functions YH_INTERNAL *fuzz_backend_functions(void);
 struct backend_functions *backend_functions(void);
 #endif
 
+void increment_ctr(uint8_t *ctr, size_t len);
+
 #endif
diff --git a/lib/lib_util.c b/lib/lib_util.c
index ee719c60..59a68e3e 100644
--- a/lib/lib_util.c
+++ b/lib/lib_util.c
@@ -181,3 +181,11 @@ bool parse_usb_url(const char *url, unsigned long *serial) {
   }
   return false;
 }
+
+void increment_ctr(uint8_t *ctr, size_t len) {
+  while (len > 0) {
+    if (++ctr[--len]) {
+      break;
+    }
+  }
+}
diff --git a/lib/yubihsm.c b/lib/yubihsm.c
index d467b729..83ff63d3 100644
--- a/lib/yubihsm.c
+++ b/lib/yubihsm.c
@@ -191,19 +191,6 @@ static
   return yrc;
 }
 
-#ifndef FUZZING
-static
-#endif
-  void
-  increment_ctr(uint8_t *ctr, uint16_t len) {
-
-  while (len > 0) {
-    if (++ctr[--len]) {
-      break;
-    }
-  }
-}
-
 static yh_rc translate_device_error(uint8_t device_error) {
 
   enum {
diff --git a/lib/yubihsm.h b/lib/yubihsm.h
index 077b7143..e70b69e6 100644
--- a/lib/yubihsm.h
+++ b/lib/yubihsm.h
@@ -3193,7 +3193,6 @@ yh_rc yh_domains_to_string(uint16_t domains, char *string, size_t max_len);
 yh_rc compute_cryptogram(const uint8_t *key, uint16_t key_len, uint8_t type,
                          const uint8_t context[SCP_CONTEXT_LEN], uint16_t L,
                          uint8_t *key_out);
-void increment_ctr(uint8_t *ctr, uint16_t len);
 #endif
 
 #endif
diff --git a/pkcs11/util_pkcs11.c b/pkcs11/util_pkcs11.c
index c65b7861..fb525e7e 100644
--- a/pkcs11/util_pkcs11.c
+++ b/pkcs11/util_pkcs11.c
@@ -6092,14 +6092,6 @@ bool match_meta_attributes(yubihsm_pkcs11_session *session,
   return true;
 }
 
-static void increment_ctr(uint8_t *ctr, size_t len) {
-  while (len > 0) {
-    if (++ctr[--len]) {
-      break;
-    }
-  }
-}
-
 CK_RV ecdh_with_kdf(ecdh_session_key *shared_secret, uint8_t *fixed_info,
                     size_t fixed_len, CK_ULONG kdf, size_t value_len) {