mirror of
https://github.com/octoleo/syncthing.git
synced 2024-11-06 05:17:49 +00:00
97 lines
2.4 KiB
Go
97 lines
2.4 KiB
Go
// Copyright (C) 2016 The Syncthing Authors.
|
|
//
|
|
// This Source Code Form is subject to the terms of the Mozilla Public
|
|
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
|
|
// You can obtain one at https://mozilla.org/MPL/2.0/.
|
|
|
|
package rand
|
|
|
|
import "testing"
|
|
|
|
func TestSecureSource(t *testing.T) {
|
|
// This is not a test to verify that the random numbers are secure,
|
|
// merely that the numbers look random at all and that we've haven't
|
|
// broken the implementation by masking off half the bits or always
|
|
// returning "4" (chosen by fair dice roll),
|
|
|
|
const nsamples = 10000
|
|
|
|
// Create a new source and sample values from it.
|
|
s := newSecureSource()
|
|
res0 := make([]int64, nsamples)
|
|
for i := range res0 {
|
|
res0[i] = s.Int63()
|
|
}
|
|
|
|
// Do it again
|
|
s = newSecureSource()
|
|
res1 := make([]int64, nsamples)
|
|
for i := range res1 {
|
|
res1[i] = s.Int63()
|
|
}
|
|
|
|
// There should (statistically speaking) be no repetition of the values,
|
|
// neither within the samples from a source nor between sources.
|
|
for _, v0 := range res0 {
|
|
for _, v1 := range res1 {
|
|
if v0 == v1 {
|
|
t.Errorf("Suspicious coincidence, %d repeated between res0/res1", v0)
|
|
}
|
|
}
|
|
}
|
|
for i, v0 := range res0 {
|
|
for _, v1 := range res0[i+1:] {
|
|
if v0 == v1 {
|
|
t.Errorf("Suspicious coincidence, %d repeated within res0", v0)
|
|
}
|
|
}
|
|
}
|
|
for i, v0 := range res1 {
|
|
for _, v1 := range res1[i+1:] {
|
|
if v0 == v1 {
|
|
t.Errorf("Suspicious coincidence, %d repeated within res1", v0)
|
|
}
|
|
}
|
|
}
|
|
|
|
// Count how many times each bit was set. On average each bit ought to
|
|
// be set in half of the samples, except the topmost bit which must
|
|
// never be set (int63). We raise an alarm if a single bit is set in
|
|
// fewer than 1/3 of the samples or more often than 2/3 of the samples.
|
|
var bits [64]int
|
|
for _, v := range res0 {
|
|
for i := range bits {
|
|
if v&1 == 1 {
|
|
bits[i]++
|
|
}
|
|
v >>= 1
|
|
}
|
|
}
|
|
for bit, count := range bits {
|
|
switch bit {
|
|
case 63:
|
|
// The topmost bit is never set
|
|
if count != 0 {
|
|
t.Errorf("The topmost bit was set %d times in %d samples (should be 0)", count, nsamples)
|
|
}
|
|
default:
|
|
if count < nsamples/3 {
|
|
t.Errorf("Bit %d was set only %d times out of %d", bit, count, nsamples)
|
|
}
|
|
if count > nsamples/3*2 {
|
|
t.Errorf("Bit %d was set fully %d times out of %d", bit, count, nsamples)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
var sink int64
|
|
|
|
func BenchmarkSecureSource(b *testing.B) {
|
|
s := newSecureSource()
|
|
for i := 0; i < b.N; i++ {
|
|
sink = s.Int63()
|
|
}
|
|
b.ReportAllocs()
|
|
}
|