func TestCounterEncIdenticalStreams(t *testing.T) {
k, err := rsa.GenerateKey(&RandSeedReader{*rand.New(rand.NewSource(0xFF43109))}, 128)
fatalOnErr(err, "rsa.GenerateKey", t)
c1, err := goproxy.NewCounterEncryptorRandFromKey(k, []byte("the quick brown fox run over the lazy dog"))
fatalOnErr(err, "NewCounterEncryptorRandFromKey", t)
c2, err := goproxy.NewCounterEncryptorRandFromKey(k, []byte("the quick brown fox run over the lazy dog"))
fatalOnErr(err, "NewCounterEncryptorRandFromKey", t)
nout := 1000
out1, out2 := make([]byte, nout), make([]byte, nout)
io.ReadFull(&c1, out1)
tmp := out2[:]
rand.Seed(0xFF43109)
for len(tmp) > 0 {
n := 1 + rand.Intn(256)
if n > len(tmp) {
n = len(tmp)
}
n, err := c2.Read(tmp[:n])
fatalOnErr(err, "CounterEncryptorRand.Read", t)
tmp = tmp[n:]
}
if !bytes.Equal(out1, out2) {
t.Error("identical CSPRNG does not produce the same output")
}
}
func TestCounterEncDifferentConsecutive(t *testing.T) {
k, err := rsa.GenerateKey(&RandSeedReader{*rand.New(rand.NewSource(0xFF43109))}, 128)
fatalOnErr(err, "rsa.GenerateKey", t)
c, err := goproxy.NewCounterEncryptorRandFromKey(k, []byte("the quick brown fox run over the lazy dog"))
fatalOnErr(err, "NewCounterEncryptorRandFromKey", t)
for i := 0; i < 100*1000; i++ {
var a, b int64
binary.Read(&c, binary.BigEndian, &a)
binary.Read(&c, binary.BigEndian, &b)
if a == b {
t.Fatal("two consecutive equal int64", a, b)
}
}
}
func TestCounterEncStreamHistogram(t *testing.T) {
k, err := rsa.GenerateKey(&RandSeedReader{*rand.New(rand.NewSource(0xFF43109))}, 128)
fatalOnErr(err, "rsa.GenerateKey", t)
c, err := goproxy.NewCounterEncryptorRandFromKey(k, []byte("the quick brown fox run over the lazy dog"))
fatalOnErr(err, "NewCounterEncryptorRandFromKey", t)
nout := 100 * 1000
out := make([]byte, nout)
io.ReadFull(&c, out)
refhist := make([]int, 256)
for i := 0; i < nout; i++ {
refhist[rand.Intn(256)]++
}
hist := make([]int, 256)
for _, b := range out {
hist[int(b)]++
}
refstddev, stddev := stddev(refhist), stddev(hist)
// due to lack of time, I guestimate
t.Logf("ref:%v - act:%v = %v", refstddev, stddev, math.Abs(refstddev-stddev))
if math.Abs(refstddev-stddev) >= 1 {
t.Errorf("stddev of ref histogram different than regular PRNG: %v %v", refstddev, stddev)
}
}