diff --git a/cdr-md5.sh b/cdr-md5.sh
index 4234c6c..2cd80f0 100755
--- a/cdr-md5.sh
+++ b/cdr-md5.sh
@@ -2,7 +2,8 @@
 error() { echo "$@"; exit 1; }
 test -n "$1" || error "Usage: $0 <cdr-file>"
 test -f "$1" || error "File '$1' not found"
-TMPFILE="/tmp/$(basename "$1").$$"
+BASECDR="$(basename "$1")"
+TMPFILE="$(mktemp -t "cdr-md5.${BASECDR}.XXXXXXXXXX")"
 MD5="$(tail -1 "$1")  ${TMPFILE}"
 sed '$d' < "$1" > "${TMPFILE}"
 echo "$MD5" | md5sum -c -