diff --git a/lib/internal.h b/lib/internal.h
index 7267d51b..8ca50164 100644
--- a/lib/internal.h
+++ b/lib/internal.h
@@ -75,6 +75,7 @@
 struct crypt_device;
 
 struct volume_key {
+	int id;
 	size_t keylength;
 	const char *key_description;
 	char key[];
@@ -84,6 +85,8 @@ struct volume_key *crypt_alloc_volume_key(size_t keylength, const char *key);
 struct volume_key *crypt_generate_volume_key(struct crypt_device *cd, size_t keylength);
 void crypt_free_volume_key(struct volume_key *vk);
 int crypt_volume_key_set_description(struct volume_key *key, const char *key_description);
+void crypt_volume_key_set_id(struct volume_key *vk, int id);
+int crypt_volume_key_get_id(const struct volume_key *vk);
 
 struct crypt_pbkdf_type *crypt_get_pbkdf(struct crypt_device *cd);
 int init_pbkdf_type(struct crypt_device *cd,
diff --git a/lib/volumekey.c b/lib/volumekey.c
index bb771039..b84cd7da 100644
--- a/lib/volumekey.c
+++ b/lib/volumekey.c
@@ -39,6 +39,7 @@ struct volume_key *crypt_alloc_volume_key(size_t keylength, const char *key)
 
 	vk->key_description = NULL;
 	vk->keylength = keylength;
+	vk->id = -1;
 
 	/* keylength 0 is valid => no key */
 	if (vk->keylength) {
@@ -64,6 +65,17 @@ int crypt_volume_key_set_description(struct volume_key *vk, const char *key_desc
 	return 0;
 }
 
+void crypt_volume_key_set_id(struct volume_key *vk, int id)
+{
+	if (vk && id >= 0)
+		vk->id = id;
+}
+
+int crypt_volume_key_get_id(const struct volume_key *vk)
+{
+	return vk ? vk->id : -1;
+}
+
 void crypt_free_volume_key(struct volume_key *vk)
 {
 	if (vk) {