diff --git a/COPYING b/COPYING
new file mode 100644
index 0000000..3fec1f6
--- /dev/null
+++ b/COPYING
@@ -0,0 +1,26 @@
+Copyright (c) 2009-2013 Yubico AB
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+  * Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+
+  * Redistributions in binary form must reproduce the above
+    copyright notice, this list of conditions and the following
+    disclaimer in the documentation and/or other materials provided
+    with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/Makefile b/Makefile
index 71c6e44..c1b0d45 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,5 @@
 # Written by Simon Josefsson <simon@josefsson.org>.
-# Copyright (c) 2009-2012 Yubico AB
+# Copyright (c) 2009-2013 Yubico AB
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
diff --git a/NEWS b/NEWS
index ea8e66d..da9081b 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,7 @@
 * Version 1.12 (unreleased)
 
+  * Added COPYING file.
+
 * Version 1.11 (released 2013-01-31)
 
   * Added missing manprefix to Makefile.
diff --git a/ykksm-decrypt.php b/ykksm-decrypt.php
index f5f333b..5fae894 100644
--- a/ykksm-decrypt.php
+++ b/ykksm-decrypt.php
@@ -1,7 +1,7 @@
 <?php
 
 # Written by Simon Josefsson <simon@josefsson.org>.
-# Copyright (c) 2009-2012 Yubico AB
+# Copyright (c) 2009-2013 Yubico AB
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
diff --git a/ykksm-gen-keys b/ykksm-gen-keys
index d8d9f11..b29a6e2 100755
--- a/ykksm-gen-keys
+++ b/ykksm-gen-keys
@@ -1,7 +1,7 @@
 #!/usr/bin/perl
 
 # Written by Simon Josefsson <simon@josefsson.org>.
-# Copyright (c) 2009-2012 Yubico AB
+# Copyright (c) 2009-2013 Yubico AB
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
diff --git a/ykksm-utils.php b/ykksm-utils.php
index a755059..4db08fa 100644
--- a/ykksm-utils.php
+++ b/ykksm-utils.php
@@ -1,7 +1,7 @@
 <?php
 
 # Written by Simon Josefsson <simon@josefsson.org>.
-# Copyright (c) 2009-2012 Yubico AB
+# Copyright (c) 2009-2013 Yubico AB
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without