Change the protocol to solve sessionTicket inconsistency

cmd/ck-client/ck-client.go

@@ -4,6 +4,7 @@ package main
 
 import (
 	"encoding/base64"
+	"encoding/binary"
 	"flag"
 	"fmt"
 	"io"
@@ -176,16 +177,18 @@ start:
 	log.Println("Attemtping to start a new session")
 	// sessionID is usergenerated. There shouldn't be a security concern because the scope of
 	// sessionID is limited to its UID.
-	rand.Seed(time.Now().UnixNano())
+	quad := make([]byte, 4)
-	sessionID := rand.Uint32()
+	rand.Read(quad)
+	sta.SessionID = binary.BigEndian.Uint32(quad)
+
+	sta.UpdateIntervalKeys()
 
 	if adminUID != nil {
-		sessionID = 0
+		sta.SessionID = 0
 		sta.UID = adminUID
 		sta.NumConn = 1
 	}
 
-	sta.SetSessionID(sessionID)
 	var crypto mux.Crypto
 	switch sta.EncryptionMethod {
 	case 0x00:
@@ -204,11 +207,8 @@ start:
 		}
 	}
 
-	sessionKey := make([]byte, 32)
+	_, tthKey, _ := sta.GetIntervalKeys()
-	rand.Read(sessionKey)
+	sesh := mux.MakeSession(sta.SessionID, mux.UNLIMITED_VALVE, mux.MakeObfs(tthKey, crypto), mux.MakeDeobfs(tthKey, crypto), util.ReadTLS)
-	sta.SessionKey = sessionKey
-
-	sesh := mux.MakeSession(sessionID, mux.UNLIMITED_VALVE, mux.MakeObfs(sta.SessionKey, crypto), mux.MakeDeobfs(sta.SessionKey, crypto), util.ReadTLS)
 
 	var wg sync.WaitGroup
 	for i := 0; i < sta.NumConn; i++ {
@@ -227,7 +227,7 @@ start:
 	}
 	wg.Wait()
 
-	log.Printf("Session %v established", sessionID)
+	log.Printf("Session %v established", sta.SessionID)
 
 	for {
 		if sesh.IsBroken() {

cmd/ck-server/ck-server.go

@@ -73,7 +73,7 @@ func dispatchConnection(conn net.Conn, sta *server.State) {
 		return
 	}
 
-	isCloak, UID, sessionID, proxyMethod, encryptionMethod, sessionKey := server.TouchStone(ch, sta)
+	isCloak, UID, sessionID, proxyMethod, encryptionMethod, tthKey := server.TouchStone(ch, sta)
 	if !isCloak {
 		log.Printf("+1 non Cloak TLS traffic from %v\n", conn.RemoteAddr())
 		goWeb(data)
@@ -109,8 +109,8 @@ func dispatchConnection(conn net.Conn, sta *server.State) {
 		return
 	}
 
-	obfs := mux.MakeObfs(sessionKey, crypto)
+	obfs := mux.MakeObfs(tthKey, crypto)
-	deobfs := mux.MakeDeobfs(sessionKey, crypto)
+	deobfs := mux.MakeDeobfs(tthKey, crypto)
 
 	finishHandshake := func() error {
 		reply := server.ComposeReply(ch)

internal/client/auth.go

@@ -1,67 +1,52 @@
 package client
 
 import (
-	"crypto"
 	"crypto/rand"
 	"crypto/sha256"
 	"encoding/binary"
-	"io"
-
 	"github.com/cbeuw/Cloak/internal/ecdh"
 	"github.com/cbeuw/Cloak/internal/util"
 )
 
-type keyPair struct {
-	crypto.PrivateKey
-	crypto.PublicKey
-}
-
 func MakeRandomField(sta *State) []byte {
+	// [4 bytes sessionId] [12 bytes random] [16 bytes hash]
 	t := make([]byte, 8)
 	binary.BigEndian.PutUint64(t, uint64(sta.Now().Unix()/(12*60*60)))
-	rdm := make([]byte, 16)
+
-	io.ReadFull(rand.Reader, rdm)
+	front := make([]byte, 16)
+	binary.BigEndian.PutUint32(front[0:4], sta.SessionID)
+	rand.Read(front[4:])
 	preHash := make([]byte, 56)
 	copy(preHash[0:32], sta.UID)
 	copy(preHash[32:40], t)
-	copy(preHash[40:56], rdm)
+	copy(preHash[40:56], front)
 	h := sha256.New()
 	h.Write(preHash)
+
 	ret := make([]byte, 32)
-	copy(ret[0:16], rdm)
+	copy(ret[0:16], front)
 	copy(ret[16:32], h.Sum(nil)[0:16])
 	return ret
 }
 
 func MakeSessionTicket(sta *State) []byte {
-	// sessionTicket: [marshalled ephemeral pub key 32 bytes][encrypted UID+sessionID 20 bytes, proxy method 16 bytes, encryption method 1 byte, sessionKey 32 bytes][16 bytes authentication tag][padding 75 bytes]
+	// sessionTicket: [marshalled ephemeral pub key 32 bytes][encrypted UID 16 bytes, proxy method 16 bytes, encryption method 1 byte][16 bytes authentication tag][padding 111 bytes]
 	// The first 12 bytes of the marshalled ephemeral public key is used as the nonce
 	// for encrypting the UID
-	tthInterval := sta.Now().Unix() / int64(sta.TicketTimeHint)
+
-	sta.keyPairsM.Lock()
-	ephKP := sta.keyPairs[tthInterval]
-	if ephKP == nil {
-		ephPv, ephPub, _ := ecdh.GenerateKey(rand.Reader)
-		ephKP = &keyPair{
-			ephPv,
-			ephPub,
-		}
-		sta.keyPairs[tthInterval] = ephKP
-	}
-	sta.keyPairsM.Unlock()
 	ticket := make([]byte, 192)
-	copy(ticket[0:32], ecdh.Marshal(ephKP.PublicKey))
-	key := ecdh.GenerateSharedSecret(ephKP.PrivateKey, sta.staticPub)
 
-	plain := make([]byte, 69)
+	//TODO: error when the interval has expired
+	ephPub, intervalKey, seed := sta.GetIntervalKeys()
+	copy(ticket[0:32], ecdh.Marshal(ephPub))
+
+	plain := make([]byte, 33)
 	copy(plain, sta.UID)
-	binary.BigEndian.PutUint32(plain[16:20], sta.sessionID)
+	copy(plain[16:32], []byte(sta.ProxyMethod))
-	copy(plain[20:36], []byte(sta.ProxyMethod))
+	plain[32] = sta.EncryptionMethod
-	plain[36] = sta.EncryptionMethod
-	copy(plain[37:69], sta.SessionKey)
 
-	cipher, _ := util.AESGCMEncrypt(ticket[0:12], key, plain)
+	cipher, _ := util.AESGCMEncrypt(ticket[0:12], intervalKey, plain)
-	copy(ticket[32:117], cipher)
+	copy(ticket[32:81], cipher)
 	// The purpose of adding sessionID is that, the generated padding of sessionTicket needs to be unpredictable.
 	// As shown in auth.go, the padding is generated by a psudo random generator. The seed
 	// needs to be the same for each TicketTimeHint interval. However the value of epoch/TicketTimeHint
@@ -72,6 +57,6 @@ func MakeSessionTicket(sta *State) []byte {
 	// With the sessionID value generated at startup of ckclient and used as a part of the seed, the
 	// sessionTicket is still identical for each TicketTimeHint interval, but others won't be able to know
 	// how it was generated. It will also be different for each client.
-	copy(ticket[117:192], util.PsudoRandBytes(75, tthInterval+int64(sta.sessionID)))
+	copy(ticket[81:192], util.PsudoRandBytes(111, seed))
 	return ticket
 }

internal/client/auth_test.go

@@ -2,6 +2,7 @@ package client
 
 import (
 	"bytes"
+	"encoding/gob"
 	//"crypto/aes"
 	//"crypto/cipher"
 	//"crypto/rand"
@@ -15,89 +16,75 @@ import (
 	//"github.com/cbeuw/Cloak/internal/ecdh"
 )
 
-/*
 func TestMakeSessionTicket(t *testing.T) {
-	UID, _ := hex.DecodeString("26a8e88bcd7c64a69ca051740851d22a6818de2fddafc00882331f1c5a8b866c")
-	staticPv, staticPub, _ := ecdh.GenerateKey(rand.Reader)
-	mockSta := &State{
-		Now:            time.Now,
-		sessionID:      42,
-		UID:            UID,
-		staticPub:      staticPub,
-		keyPairs:       make(map[int64]*keyPair),
-		TicketTimeHint: 3600,
-	}
 
+	stateGob, _ := hex.DecodeString("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")
+	buf := bytes.NewBuffer(stateGob)
+	mockSta := &State{}
+	gob.NewDecoder(buf).Decode(mockSta)
+	mockSta.intervalData = &tthIntervalKeys{}
+	mockSta.intervalData.interval = 434487
+	ephPub, _ := hex.DecodeString("7b7e0db16bb8c83355771a424234e36c02fd752b6a9310968d27787d7c117b10")
+	ephPv, _ := hex.DecodeString("68584fed8ede64e2b17619b9cc0effb2678feb2face92456a8414dafa629334b")
+	mockSta.intervalData.intervalKey, _ = hex.DecodeString("47e1c2413f1a6b397fbd61d6cf21397b20a2338cef48fae68643602881d93d4b")
+	mockSta.intervalData.seed = 7518847459617826018
+	staticPub, _ := hex.DecodeString("218a14ce495efd3fe4ae213e51f766ec01d0b487869c159b8619536e60e95142")
+
+	var a, b, c [32]byte
+	copy(a[:], ephPub)
+	copy(b[:], ephPv)
+	copy(c[:], staticPub)
+	mockSta.intervalData.ephPub = &a
+	mockSta.intervalData.ephPv = &b
+	mockSta.staticPub = &c
+
+	target, _ := hex.DecodeString("7b7e0db16bb8c83355771a424234e36c02fd752b6a9310968d27787d7c117b103a2d246fd8b7d9e4243d6b83a7365858bd9cb583ba950287c4f4edc249cea935e235eda92c48569f455fca34ff6e4d37cf8f519b1d66e7cd51b31c1766ffb03134576e8d61ad5eae58a9ce4153ec33af73c7a8d04ab56d51155ac19fe731c792c17ee98a97fbfef8efc952964b7fd61dd2a35d7de4128abc730e20ba44e069e44ba8e29b66a8e4f114b9ab4cc2fba944a925086d7f09892a59147d990b58d393")
 	ticket := MakeSessionTicket(mockSta)
 
-	// verification
+	if !bytes.Equal(target, ticket) {
-	ephPub, _ := ecdh.Unmarshal(ticket[0:32])
-	key := ecdh.GenerateSharedSecret(staticPv, ephPub)
-
-	// aes decrypt
-	UIDsID := make([]byte, len(ticket[32:68]))
-	copy(UIDsID, ticket[32:68]) // Because XORKeyStream is inplace, but we don't want the input to be changed
-	block, _ := aes.NewCipher(key)
-	stream := cipher.NewCTR(block, ticket[0:16])
-	stream.XORKeyStream(UIDsID, UIDsID)
-
-	decryUID := UIDsID[0:32]
-	decrySessionID := binary.BigEndian.Uint32(UIDsID[32:36])
-
-	// check padding
-	tthInterval := mockSta.Now().Unix() / int64(mockSta.TicketTimeHint)
-	r := prand.New(prand.NewSource(tthInterval + int64(mockSta.sessionID)))
-	pad := make([]byte, 124)
-	r.Read(pad)
-
-	if !bytes.Equal(mockSta.UID, decryUID) {
 		t.Error(
-			"For", "UID",
+			"For", "sessionTicket generation",
-			"expecting", fmt.Sprintf("%x", mockSta.UID),
+			"expecting", fmt.Sprintf("%x", target),
-			"got", fmt.Sprintf("%x", decryUID),
+			"got", fmt.Sprintf("%x", ticket),
-		)
-	}
-	if mockSta.sessionID != decrySessionID {
-		t.Error(
-			"For", "sessionID",
-			"expecting", mockSta.sessionID,
-			"got", decrySessionID,
-		)
-	}
-	if !bytes.Equal(pad, ticket[68:]) {
-		t.Error(
-			"For", "Padding",
-			"expecting", fmt.Sprintf("%x", pad),
-			"got", fmt.Sprintf("%x", ticket[68:]),
 		)
 	}
+
 }
-*/
 
 func TestMakeRandomField(t *testing.T) {
-	UID, _ := hex.DecodeString("26a8e88bcd7c64a69ca051740851d22a6818de2fddafc00882331f1c5a8b866c")
+	UID, _ := hex.DecodeString("4cd8cc15600d7eb68131fd8097673746")
 	mockSta := &State{
 		Now:       time.Now,
 		UID:       UID,
+		SessionID: 1,
 	}
 	random := MakeRandomField(mockSta)
 
 	// verification
 	tb := make([]byte, 8)
 	binary.BigEndian.PutUint64(tb, uint64(time.Now().Unix()/(12*60*60)))
-	rdm := random[0:16]
+	front := random[0:16]
 	preHash := make([]byte, 56)
 	copy(preHash[0:32], UID)
 	copy(preHash[32:40], tb)
-	copy(preHash[40:56], rdm)
+	copy(preHash[40:56], front)
 	h := sha256.New()
 	h.Write(preHash)
 	exp := h.Sum(nil)[0:16]
 	if !bytes.Equal(exp, random[16:32]) {
 		t.Error(
-			"For", "Random",
+			"For", "Random generation",
 			"expecting", fmt.Sprintf("%x", exp),
 			"got", fmt.Sprintf("%x", random[16:32]),
 		)
 	}
+
+	random2 := MakeRandomField(mockSta)
+	if bytes.Equal(random, random2) {
+		t.Error(
+			"For", "Duplicate random generation",
+			"expecting", "two different randoms",
+			"got", fmt.Sprintf("the same: %x", random),
+		)
+	}
 }

internal/client/state.go

@@ -2,7 +2,9 @@ package client
 
 import (
 	"crypto"
+	"crypto/rand"
 	"encoding/base64"
+	"encoding/binary"
 	"encoding/json"
 	"errors"
 	"io/ioutil"
@@ -24,6 +26,14 @@ type rawConfig struct {
 	NumConn          int
 }
 
+type tthIntervalKeys struct {
+	interval    int64
+	ephPv       crypto.PrivateKey
+	ephPub      crypto.PublicKey
+	intervalKey []byte
+	seed        int64
+}
+
 // State stores global variables
 type State struct {
 	LocalHost  string
@@ -32,12 +42,12 @@ type State struct {
 	RemotePort string
 
 	Now       func() time.Time
-	sessionID  uint32
+	SessionID uint32
-	SessionKey []byte
 	UID       []byte
 	staticPub crypto.PublicKey
-	keyPairsM  sync.RWMutex
+
-	keyPairs   map[int64]*keyPair
+	intervalDataM sync.Mutex
+	intervalData  *tthIntervalKeys
 
 	ProxyMethod      string
 	EncryptionMethod byte
@@ -54,12 +64,31 @@ func InitState(localHost, localPort, remoteHost, remotePort string, nowFunc func
 		RemoteHost:   remoteHost,
 		RemotePort:   remotePort,
 		Now:          nowFunc,
+		intervalData: &tthIntervalKeys{},
 	}
-	ret.keyPairs = make(map[int64]*keyPair)
 	return ret
 }
 
-func (sta *State) SetSessionID(id uint32) { sta.sessionID = id }
+func (sta *State) UpdateIntervalKeys() {
+	sta.intervalDataM.Lock()
+	currentInterval := sta.Now().Unix() / int64(sta.TicketTimeHint)
+	if currentInterval == sta.intervalData.interval {
+		sta.intervalDataM.Unlock()
+		return
+	}
+	sta.intervalData.interval = currentInterval
+	ephPv, ephPub, _ := ecdh.GenerateKey(rand.Reader)
+	intervalKey := ecdh.GenerateSharedSecret(ephPv, sta.staticPub)
+	seed := int64(binary.BigEndian.Uint64(ephPv.(*[32]byte)[0:8]))
+	sta.intervalData.ephPv, sta.intervalData.ephPub, sta.intervalData.intervalKey, sta.intervalData.seed = ephPv, ephPub, intervalKey, seed
+	sta.intervalDataM.Unlock()
+}
+
+func (sta *State) GetIntervalKeys() (crypto.PublicKey, []byte, int64) {
+	sta.intervalDataM.Lock()
+	defer sta.intervalDataM.Unlock()
+	return sta.intervalData.ephPub, sta.intervalData.intervalKey, sta.intervalData.seed
+}
 
 // semi-colon separated value. This is for Android plugin options
 func ssvToJson(ssv string) (ret []byte) {

internal/server/auth.go

@@ -5,37 +5,37 @@ import (
 	"crypto"
 	"crypto/sha256"
 	"encoding/binary"
-	"log"
-
 	"github.com/cbeuw/Cloak/internal/ecdh"
 	"github.com/cbeuw/Cloak/internal/util"
+	"log"
 )
 
-// input ticket, return UID
+func decryptSessionTicket(staticPv crypto.PrivateKey, ticket []byte) (UID []byte, proxyMethod string, encryptionMethod byte, tthKey []byte) {
-func decryptSessionTicket(staticPv crypto.PrivateKey, ticket []byte) ([]byte, uint32, string, byte, []byte) {
+	// sessionTicket: [marshalled ephemeral pub key 32 bytes][encrypted UID 16 bytes, proxy method 16 bytes, encryption method 1 byte][16 bytes authentication tag][padding 111 bytes]
 	ephPub, _ := ecdh.Unmarshal(ticket[0:32])
-	key := ecdh.GenerateSharedSecret(staticPv, ephPub)
+	tthKey = ecdh.GenerateSharedSecret(staticPv, ephPub)
-	plain, err := util.AESGCMDecrypt(ticket[0:12], key, ticket[32:117])
+	plain, err := util.AESGCMDecrypt(ticket[0:12], tthKey, ticket[32:81])
 	if err != nil {
-		return nil, 0, "", 0x00, nil
+		return
 	}
-	sessionID := binary.BigEndian.Uint32(plain[16:20])
+	return plain[0:16], string(bytes.Trim(plain[16:32], "\x00")), plain[32], tthKey
-	return plain[0:16], sessionID, string(bytes.Trim(plain[20:36], "\x00")), plain[36], plain[37:69]
 }
 
-func validateRandom(random []byte, UID []byte, time int64) bool {
+func validateRandom(random []byte, UID []byte, time int64) (bool, uint32) {
 	t := make([]byte, 8)
 	binary.BigEndian.PutUint64(t, uint64(time/(12*60*60)))
-	rdm := random[0:16]
+	front := random[0:16]
 	preHash := make([]byte, 56)
 	copy(preHash[0:32], UID)
 	copy(preHash[32:40], t)
-	copy(preHash[40:56], rdm)
+	copy(preHash[40:56], front)
 	h := sha256.New()
 	h.Write(preHash)
-	return bytes.Equal(h.Sum(nil)[0:16], random[16:32])
+
+	sessionID := binary.BigEndian.Uint32(front[0:4])
+	return bytes.Equal(h.Sum(nil)[0:16], random[16:32]), sessionID
 }
-func TouchStone(ch *ClientHello, sta *State) (isCK bool, UID []byte, sessionID uint32, proxyMethod string, encryptionMethod byte, sessionKey []byte) {
+func TouchStone(ch *ClientHello, sta *State) (isCK bool, UID []byte, sessionID uint32, proxyMethod string, encryptionMethod byte, tthKey []byte) {
 	var random [32]byte
 	copy(random[:], ch.random)
 
@@ -50,14 +50,17 @@ func TouchStone(ch *ClientHello, sta *State) (isCK bool, UID []byte, sessionID u
 	}
 
 	ticket := ch.extensions[[2]byte{0x00, 0x23}]
-	if len(ticket) < 68 {
+
+	if len(ticket) < 81 {
 		return
 	}
-	UID, sessionID, proxyMethod, encryptionMethod, sessionKey = decryptSessionTicket(sta.staticPv, ticket)
+
+	UID, proxyMethod, encryptionMethod, tthKey = decryptSessionTicket(sta.staticPv, ticket)
+
 	if len(UID) < 16 {
 		return
 	}
-	isCK = validateRandom(ch.random, UID, sta.Now().Unix())
+	isCK, sessionID = validateRandom(ch.random, UID, sta.Now().Unix())
 	if !isCK {
 		return
 	}

internal/server/auth_test.go

@@ -1,22 +1,27 @@
 package server
 
 import (
+	"bytes"
 	//"bytes"
 	"encoding/hex"
 	"fmt"
+	"github.com/cbeuw/Cloak/internal/ecdh"
 	"testing"
 	//"github.com/cbeuw/Cloak/internal/ecdh"
 )
 
-/*
 func TestDecryptSessionTicket(t *testing.T) {
-	UID, _ := hex.DecodeString("26a8e88bcd7c64a69ca051740851d22a6818de2fddafc00882331f1c5a8b866c")
+	UID, _ := hex.DecodeString("4cd8cc15600d7eb68131fd8097673746")
-	sessionID := uint32(42)
+	pvb, _ := hex.DecodeString("10de5a3c4a4d04efafc3e06d1506363a72bd6d053baef123e6a9a79a0c04b547")
-	pvb, _ := hex.DecodeString("083794692e77b28fa2152dfee53142185fd58ea8172d3545fdeeaea97b3c597c")
 	staticPv, _ := ecdh.Unmarshal(pvb)
-	sessionTicket, _ := hex.DecodeString("f586223b50cada583d61dc9bf3d01cc3a45aab4b062ed6a31ead0badb87f7761aab4f9f737a1d8ff2a2aa4d50ceb808844588ee3c8fdf36c33a35ef5003e287337659c8164a7949e9e63623090763fc24d0386c8904e47bdd740e09dd9b395c72de669629c2a865ed581452d23306adf26de0c8a46ee05e3dac876f2bcd9a2de946d319498f579383d06b3e66b3aca05f533fdc5f017eeba45b42080aabd4f71151fa0dfc1b0e23be4ed3abdb47adc0d5740ca7b7689ad34426309fb6984a086")
+	proxyMethod := "shadowsocks"
+	encryptionMethod := byte(0)
+	tthKey, _ := hex.DecodeString("92389a9b2769e2b76514c4cb163217bed0c5500bceb4a5ade1ceae597616db23")
+
+	sessionTicket, _ := hex.DecodeString("9ee339202508b6fbe9c19988575330c547efbc27b0d072ed93c0cc265b67d826825a49211b8f86b4364b436ed5db15925774c3bec4a1776f70a17db68ba541dc4c23871d2cc1a5074b081bbe0f8b86f1c7f7749964517dcfd8830532eddc8ac707544ec04b754a133b9595ebc2af988156dbe1e4f3b89c9dc289d441cb5a15d72cc59423981d43a498292d509e5fa5c8e8bf8ee85a2e4991ae126fcd6e4d2aa1119e918c80afa2dc38bec1ef621c9c3994af43b1983c241c68e04e8043c95d74")
+
+	decryUID, decryProxyMethod, decryEncryptionMethod, decryTthKey := decryptSessionTicket(staticPv, sessionTicket)
 
-	decryUID, decrySessionID, _, _ := decryptSessionTicket(staticPv, sessionTicket)
 	if !bytes.Equal(decryUID, UID) {
 		t.Error(
 			"For", "UID",
@@ -24,43 +29,65 @@ func TestDecryptSessionTicket(t *testing.T) {
 			"got", fmt.Sprintf("%x", decryUID),
 		)
 	}
-	if decrySessionID != sessionID {
+	if proxyMethod != decryProxyMethod {
 		t.Error(
-			"For", "sessionID",
+			"For", "proxyMethod",
-			"expecting", fmt.Sprintf("%x", sessionID),
+			"expecting", fmt.Sprintf("%x", proxyMethod),
-			"got", fmt.Sprintf("%x", decrySessionID),
+			"got", fmt.Sprintf("%x", decryProxyMethod),
+		)
+	}
+	if encryptionMethod != decryEncryptionMethod {
+		t.Error(
+			"For", "encryptionMethod",
+			"expecting", fmt.Sprintf("%x", encryptionMethod),
+			"got", fmt.Sprintf("%x", decryEncryptionMethod),
+		)
+	}
+	if !bytes.Equal(tthKey, decryTthKey) {
+		t.Error(
+			"For", "tthKey",
+			"expecting", fmt.Sprintf("%x", tthKey),
+			"got", fmt.Sprintf("%x", decryTthKey),
 		)
 	}
 
 }
-*/
 
 func TestValidateRandom(t *testing.T) {
-	UID, _ := hex.DecodeString("26a8e88bcd7c64a69ca051740851d22a6818de2fddafc00882331f1c5a8b866c")
+	sessionID := uint32(2422026642)
-	random, _ := hex.DecodeString("6274de9992a6f96a86fc35cf6644a5e7844951889a802e9531add440eabb939b")
+	random, _ := hex.DecodeString("905d319272711946f6400db4f5028d6893f7b22659c78371c1f72386191a8ab4")
-	right := validateRandom(random, UID, 1547912444)
+	UID, _ := hex.DecodeString("4cd8cc15600d7eb68131fd8097673746")
+
+	right, decrySessionID := validateRandom(random, UID, 1564150721)
 	if !right {
 		t.Error(
-			"For", fmt.Sprintf("good random: %x at time %v", random, 1547912444),
+			"For", fmt.Sprintf("good random: %x at time %v", random, 1564150721),
 			"expecting", true,
 			"got", false,
 		)
 	}
+	if sessionID != decrySessionID {
+		t.Error(
+			"For", fmt.Sprintf("good random: %x at time %v", random, 1564150721),
+			"expecting", sessionID,
+			"got", decrySessionID,
+		)
+	}
 
-	replay := validateRandom(random, UID, 1547955645)
+	replay, _ := validateRandom(random, UID, 1764150721)
 	if replay {
 		t.Error(
-			"For", fmt.Sprintf("expired random: %x at time %v", random, 1547955645),
+			"For", fmt.Sprintf("expired random: %x at time %v", random, 1764150721),
 			"expecting", false,
 			"got", true,
 		)
 	}
 
 	random[13] = 0x42
-	bogus := validateRandom(random, UID, 1547912444)
+	bogus, _ := validateRandom(random, UID, 1564150721)
 	if bogus {
 		t.Error(
-			"For", fmt.Sprintf("bogus random: %x at time %v", random, 1547912444),
+			"For", fmt.Sprintf("bogus random: %x at time %v", random, 1564150721),
 			"expecting", false,
 			"got", true,
 		)