logic/accesskeys: math.Rand -> crypto.Rand

This replaces the usage of the non-cryptographically
secure math.Rand with the system CSPRNG accessed via crypto.Rand.

Signed-off-by: John Sahhar <john@gravitl.com>

logic/accesskeys_test.go

@@ -0,0 +1,23 @@
+package logic
+
+import "testing"
+
+func Test_genKeyName(t *testing.T) {
+	for i := 0; i < 100; i++ {
+		kname := genKeyName()
+		t.Log(kname)
+		if len(kname) != 20 {
+			t.Fatalf("improper length of key name, expected 20 got :%d", len(kname))
+		}
+	}
+}
+
+func Test_genKey(t *testing.T) {
+	for i := 0; i < 100; i++ {
+		kname := genKey()
+		t.Log(kname)
+		if len(kname) != 16 {
+			t.Fatalf("improper length of key name, expected 16 got :%d", len(kname))
+		}
+	}
+}