Use strong random number generator.

src/app/spreed-speakfreely-server/random.go

@@ -21,7 +21,8 @@
 package main
 
 import (
-	"math/rand"
+	"crypto/rand"
+	pseudoRand "math/rand"
 	"time"
 )
 
@@ -32,14 +33,22 @@ const (
 func RandomString(length int) string {
 
 	buf := make([]byte, length)
-	for i := 0; i < length; i++ {
-		buf[i] = dict[rand.Intn(len(dict)-1)]
+	_, err := rand.Read(buf)
+	if err != nil {
+		// fallback to pseudo-random
+		for i := 0; i < length; i++ {
+			buf[i] = dict[pseudoRand.Intn(len(dict))]
+		}
+	} else {
+		for i := 0; i < length; i++ {
+			buf[i] = dict[int(buf[i])%len(dict)]
+		}
 	}
 	return string(buf)
 
 }
 
 func init() {
-	// Make sure to seed dsfault random generator.
-	rand.Seed(time.Now().UTC().UnixNano())
+	// Make sure to seed default random generator.
+	pseudoRand.Seed(time.Now().UTC().UnixNano())
 }