diff --git a/api/handler/acl.go b/api/handler/acl.go
index 5e52624..8a0bded 100644
--- a/api/handler/acl.go
+++ b/api/handler/acl.go
@@ -596,7 +596,7 @@ func (h *handler) PutBucketPolicyHandler(w http.ResponseWriter, r *http.Request)
 }
 
 func getBucketChainID(bktInfo *data.BucketInfo) chain.ID {
-	return chain.ID("bkt" + string(bktInfo.CID[:]))
+	return chain.ID(string(chain.S3) + ":bkt" + string(bktInfo.CID[:]))
 }
 
 func parseACLHeaders(header http.Header, key *keys.PublicKey) (*AccessControlPolicy, error) {