1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
|
package whisper
import (
"crypto/ecdsa"
"encoding/binary"
"fmt"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/crypto/ecies"
"github.com/ethereum/go-ethereum/rlp"
)
const (
DefaultPow = 50 * time.Millisecond
)
type Envelope struct {
Expiry uint32 // Whisper protocol specifies int32, really should be int64
Ttl uint32 // ^^^^^^
Topics [][]byte
Data []byte
Nonce uint32
hash Hash
}
func (self *Envelope) Hash() Hash {
if self.hash == EmptyHash {
enc, _ := rlp.EncodeToBytes(self)
self.hash = H(crypto.Sha3(enc))
}
return self.hash
}
func NewEnvelope(ttl time.Duration, topics [][]byte, data *Message) *Envelope {
exp := time.Now().Add(ttl)
return &Envelope{uint32(exp.Unix()), uint32(ttl.Seconds()), topics, data.Bytes(), 0, Hash{}}
}
func (self *Envelope) Seal(pow time.Duration) {
self.proveWork(pow)
}
func (self *Envelope) Open(prv *ecdsa.PrivateKey) (msg *Message, err error) {
data := self.Data
var message Message
dataStart := 1
if data[0] > 0 {
if len(data) < 66 {
return nil, fmt.Errorf("unable to open envelope. First bit set but len(data) < 66")
}
dataStart = 66
message.Flags = data[0]
message.Signature = data[1:66]
}
payload := data[dataStart:]
if prv != nil {
message.Payload, err = crypto.Decrypt(prv, payload)
switch err {
case nil: // OK
case ecies.ErrInvalidPublicKey: // Payload isn't encrypted
message.Payload = payload
return &message, err
default:
return nil, fmt.Errorf("unable to open envelope. Decrypt failed: %v", err)
}
}
return &message, nil
}
func (self *Envelope) proveWork(dura time.Duration) {
var bestBit int
d := make([]byte, 64)
enc, _ := rlp.EncodeToBytes(self.withoutNonce())
copy(d[:32], enc)
then := time.Now().Add(dura).UnixNano()
for n := uint32(0); time.Now().UnixNano() < then; {
for i := 0; i < 1024; i++ {
binary.BigEndian.PutUint32(d[60:], n)
fbs := common.FirstBitSet(common.BigD(crypto.Sha3(d)))
if fbs > bestBit {
bestBit = fbs
self.Nonce = n
}
n++
}
}
}
func (self *Envelope) valid() bool {
d := make([]byte, 64)
enc, _ := rlp.EncodeToBytes(self.withoutNonce())
copy(d[:32], enc)
binary.BigEndian.PutUint32(d[60:], self.Nonce)
return common.FirstBitSet(common.BigD(crypto.Sha3(d))) > 0
}
func (self *Envelope) withoutNonce() interface{} {
return []interface{}{self.Expiry, self.Ttl, self.Topics, self.Data}
}
// rlpenv is an Envelope but is not an rlp.Decoder.
// It is used for decoding because we need to
type rlpenv Envelope
func (self *Envelope) DecodeRLP(s *rlp.Stream) error {
raw, err := s.Raw()
if err != nil {
return err
}
if err := rlp.DecodeBytes(raw, (*rlpenv)(self)); err != nil {
return err
}
self.hash = H(crypto.Sha3(raw))
return nil
}
|
