func (dag *Dagger) Eval(N *big.Int) *big.Int {
pow := common.BigPow(2, 26)
dag.xn = pow.Div(N, pow)
sha := sha3.NewKeccak256()
sha.Reset()
ret := new(big.Int)
for k := 0; k < 4; k++ {
d := sha3.NewKeccak256()
b := new(big.Int)
d.Reset()
d.Write(dag.hash.Bytes())
d.Write(dag.xn.Bytes())
d.Write(N.Bytes())
d.Write(big.NewInt(int64(k)).Bytes())
b.SetBytes(Sum(d))
pk := (b.Uint64() & 0x1ffffff)
sha.Write(dag.Node(9, pk).Bytes())
}
return ret.SetBytes(Sum(sha))
}
// secrets is called after the handshake is completed.
// It extracts the connection secrets from the handshake values.
func (h *encHandshake) secrets(auth, authResp []byte) (secrets, error) {
ecdheSecret, err := h.randomPrivKey.GenerateShared(h.remoteRandomPub, sskLen, sskLen)
if err != nil {
return secrets{}, err
}
// derive base secrets from ephemeral key agreement
sharedSecret := crypto.Sha3(ecdheSecret, crypto.Sha3(h.respNonce, h.initNonce))
aesSecret := crypto.Sha3(ecdheSecret, sharedSecret)
s := secrets{
RemoteID: h.remoteID,
AES: aesSecret,
MAC: crypto.Sha3(ecdheSecret, aesSecret),
Token: crypto.Sha3(sharedSecret),
}
// setup sha3 instances for the MACs
mac1 := sha3.NewKeccak256()
mac1.Write(xor(s.MAC, h.respNonce))
mac1.Write(auth)
mac2 := sha3.NewKeccak256()
mac2.Write(xor(s.MAC, h.initNonce))
mac2.Write(authResp)
if h.initiator {
s.EgressMAC, s.IngressMAC = mac1, mac2
} else {
s.EgressMAC, s.IngressMAC = mac2, mac1
}
return s, nil
}
func (dag *Dagger) Node(L uint64, i uint64) *big.Int {
if L == i {
return dag.hash
}
var m *big.Int
if L == 9 {
m = big.NewInt(16)
} else {
m = big.NewInt(3)
}
sha := sha3.NewKeccak256()
sha.Reset()
d := sha3.NewKeccak256()
b := new(big.Int)
ret := new(big.Int)
for k := 0; k < int(m.Uint64()); k++ {
d.Reset()
d.Write(dag.hash.Bytes())
d.Write(dag.xn.Bytes())
d.Write(big.NewInt(int64(L)).Bytes())
d.Write(big.NewInt(int64(i)).Bytes())
d.Write(big.NewInt(int64(k)).Bytes())
b.SetBytes(Sum(d))
pk := b.Uint64() & ((1 << ((L - 1) * 3)) - 1)
sha.Write(dag.Node(L-1, pk).Bytes())
}
ret.SetBytes(Sum(sha))
return ret
}
func TestRLPXFrameRW(t *testing.T) {
var (
aesSecret = make([]byte, 16)
macSecret = make([]byte, 16)
egressMACinit = make([]byte, 32)
ingressMACinit = make([]byte, 32)
)
for _, s := range [][]byte{aesSecret, macSecret, egressMACinit, ingressMACinit} {
rand.Read(s)
}
conn := new(bytes.Buffer)
s1 := secrets{
AES: aesSecret,
MAC: macSecret,
EgressMAC: sha3.NewKeccak256(),
IngressMAC: sha3.NewKeccak256(),
}
s1.EgressMAC.Write(egressMACinit)
s1.IngressMAC.Write(ingressMACinit)
rw1 := newRLPXFrameRW(conn, s1)
s2 := secrets{
AES: aesSecret,
MAC: macSecret,
EgressMAC: sha3.NewKeccak256(),
IngressMAC: sha3.NewKeccak256(),
}
s2.EgressMAC.Write(ingressMACinit)
s2.IngressMAC.Write(egressMACinit)
rw2 := newRLPXFrameRW(conn, s2)
// send some messages
for i := 0; i < 10; i++ {
// write message into conn buffer
wmsg := []interface{}{"foo", "bar", strings.Repeat("test", i)}
err := Send(rw1, uint64(i), wmsg)
if err != nil {
t.Fatalf("WriteMsg error (i=%d): %v", i, err)
}
// read message that rw1 just wrote
msg, err := rw2.ReadMsg()
if err != nil {
t.Fatalf("ReadMsg error (i=%d): %v", i, err)
}
if msg.Code != uint64(i) {
t.Fatalf("msg code mismatch: got %d, want %d", msg.Code, i)
}
payload, _ := ioutil.ReadAll(msg.Payload)
wantPayload, _ := rlp.EncodeToBytes(wmsg)
if !bytes.Equal(payload, wantPayload) {
t.Fatalf("msg payload mismatch:\ngot %x\nwant %x", payload, wantPayload)
}
}
}
func newTestTransport(id discover.NodeID, fd net.Conn) transport {
wrapped := newRLPX(fd).(*rlpx)
wrapped.rw = newRLPXFrameRW(fd, secrets{
MAC: zero16,
AES: zero16,
IngressMAC: sha3.NewKeccak256(),
EgressMAC: sha3.NewKeccak256(),
})
return &testTransport{id: id, rlpx: wrapped}
}
func Sha3(data ...[]byte) []byte {
d := sha3.NewKeccak256()
for _, b := range data {
d.Write(b)
}
return d.Sum(nil)
}
func Sha3Hash(data ...[]byte) (h common.Hash) {
d := sha3.NewKeccak256()
for _, b := range data {
d.Write(b)
}
d.Sum(h[:0])
return h
}
func verify(hash common.Hash, diff *big.Int, nonce uint64) bool {
sha := sha3.NewKeccak256()
n := make([]byte, 8)
binary.PutUvarint(n, nonce)
sha.Write(n)
sha.Write(hash[:])
verification := new(big.Int).Div(common.BigPow(2, 256), diff)
res := common.BigD(sha.Sum(nil))
return res.Cmp(verification) <= 0
}
func rlpHash(x interface{}) (h common.Hash) {
hw := sha3.NewKeccak256()
rlp.Encode(hw, x)
hw.Sum(h[:0])
return h
}
// TODO: copied from crypto.go , move to sha3 package?
func Sha3(data []byte) []byte {
d := sha3.NewKeccak256()
d.Write(data)
return d.Sum(nil)
}