diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..99fd8ae
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module github.com/chrj/smtpd
+
+require github.com/eaigner/dkim v0.0.0-20150301120808-6fe4a7ee9cfb
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..0d11b77
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,2 @@
+github.com/eaigner/dkim v0.0.0-20150301120808-6fe4a7ee9cfb h1:17kQ+7S0aEyRhZd9KCAofvKlL1N1/w+zUZKaxpLFpM0=
+github.com/eaigner/dkim v0.0.0-20150301120808-6fe4a7ee9cfb/go.mod h1:FSCIHbrqk7D01Mj8y/jW+NS1uoCerr+ad+IckTHTFf4=