--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/common/random.go	Wed Aug 15 15:55:41 2018 +0200
@@ -0,0 +1,48 @@
+package common
+
+import (
+	"bytes"
+	"crypto/rand"
+	"io"
+	"log"
+	"math/big"
+)
+
+func GenerateRandomKey(length int) []byte {
+	k := make([]byte, length)
+	if _, err := io.ReadFull(rand.Reader, k); err != nil {
+		return nil
+	}
+	return k
+}
+
+func RandomString(n int) string {
+
+	const (
+		special  = "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~"
+		alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
+			"abcdefghijklmnopqrstuvwxyz" +
+			"0123456789" +
+			special
+	)
+
+	max := big.NewInt(int64(len(alphabet)))
+	out := make([]byte, n)
+
+	for i := 0; i < 1000; i++ {
+		for i := range out {
+			v, err := rand.Int(rand.Reader, max)
+			if err != nil {
+				log.Panicf("error: %v\n", err)
+			}
+			out[i] = alphabet[v.Int64()]
+		}
+		// Ensure at least one special char.
+		if bytes.IndexAny(out, special) >= 0 {
+			return string(out)
+		}
+	}
+	log.Println("warn: Your random generator may be broken.")
+	out[0] = special[0]
+	return string(out)
+}