add random test

Author: xtaci

qpp.go

@@ -197,21 +197,21 @@ func (qpp *QuantumPermutationPad) DecryptWithPRNG(data []byte, rand *Rand) {
 
 	// handle unaligned 8bytes
 	if count != 0 {
-		i := 0
-		for ; i < len(data); i++ {
+		offset := 0
+		for ; offset < len(data); offset++ {
 			rr = byte(r >> (count * 8))
-			data[i] = *(*byte)(unsafe.Pointer(base + uintptr(data[i]))) ^ rr
+			data[offset] = *(*byte)(unsafe.Pointer(base + uintptr(data[offset]))) ^ rr
 			count++
 
 			if count == PAD_SWITCH {
 				r = xorshift64star(r)
 				base = qpp.rpadsPtr + uintptr(uint16(r)%qpp.numPads)<<8
-				i = i + 1
+				offset = offset + 1
 				count = 0
 				break
 			}
 		}
-		data = data[i:]
+		data = data[offset:]
 	}
 
 	// handle 8-bytes aligned

qpp_test.go

@@ -84,10 +84,43 @@ func TestEncryption3(t *testing.T) {
 	assert.NotEqual(t, original, msg, "not encrypted")
 
 	// 12 = 9 + 1 + 2
-	//receiver.Decrypt(msg[:9])
-	//receiver.Decrypt(msg[9:10])
-	//receiver.Decrypt(msg[10:])
-	receiver.Decrypt(msg)
+	receiver.Decrypt(msg[:9])
+	receiver.Decrypt(msg[9:10])
+	receiver.Decrypt(msg[10:])
+	//receiver.Decrypt(msg)
+	assert.Equal(t, original, msg, "not equal")
+}
+
+func TestEncryptionRandLength(t *testing.T) {
+	seed := make([]byte, 32)
+	io.ReadFull(rand.Reader, seed)
+
+	sender := NewQPP(seed, 1024)
+	receiver := NewQPP(seed, 1024)
+
+	original := make([]byte, 10*1024*1024)
+	io.ReadFull(rand.Reader, original)
+	msg := make([]byte, len(original))
+	copy(msg, original)
+
+	// 12 == 3 + 5 + 4
+	start := msg
+	for len(start) > 0 {
+		l := mathrand.Intn(len(start)+1) % 256
+		sender.Encrypt(start[:l])
+		start = start[l:]
+	}
+	//sender.Encrypt(msg)
+	assert.NotEqual(t, original, msg, "not encrypted")
+
+	// 12 = 9 + 1 + 2
+	start = msg
+	for len(start) > 0 {
+		l := mathrand.Intn(len(start)+1) % 256
+		receiver.Decrypt(start[:l])
+		start = start[l:]
+	}
+	//receiver.Decrypt(msg)
 	assert.Equal(t, original, msg, "not equal")
 }