diff --git a/debian/grep_dd_sigs b/debian/grep_dd_sigs
index 7ae0ee4..438723c 100755
--- a/debian/grep_dd_sigs
+++ b/debian/grep_dd_sigs
@@ -1,5 +1,20 @@
 #!/bin/sh
 
+# Copyright: Thomas Preud'homme (2011)
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 sigs=$(gpg --with-colons --check-sigs $1 \
 	| grep "sig:\!" \
 	| sed -r "s/sig:\!::[[:digit:]]+:([[:alnum:]]+):.*$/\1/")