diff --git a/characterize.go b/characterize.go
index 96e7bee..735c278 100644
--- a/characterize.go
+++ b/characterize.go
@@ -1,4 +1,17 @@
 // Copyright 2015 Richard Lehane.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
 // Golang port of encoding.c from the file command
 // https://github.com/file/file/blob/master/src/encoding.c
 // Original copyright notice: