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
125
126
127
|
package whisper
import (
"bytes"
"crypto/ecdsa"
"encoding/binary"
"fmt"
"io"
"time"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/ethutil"
"github.com/ethereum/go-ethereum/rlp"
"github.com/obscuren/ecies"
)
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 NewEnvelopeFromReader(reader io.Reader) (*Envelope, error) {
var envelope Envelope
buf := new(bytes.Buffer)
buf.ReadFrom(reader)
h := H(crypto.Sha3(buf.Bytes()))
if err := rlp.Decode(buf, &envelope); err != nil {
return nil, err
}
envelope.hash = h
return &envelope, nil
}
func (self *Envelope) Hash() Hash {
if self.hash == EmptyHash {
self.hash = H(crypto.Sha3(ethutil.Encode(self)))
}
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 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)
copy(d[:32], ethutil.Encode(self.withoutNonce()))
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 := ethutil.FirstBitSet(ethutil.BigD(crypto.Sha3(d)))
if fbs > bestBit {
bestBit = fbs
self.Nonce = n
}
n++
}
}
}
func (self *Envelope) valid() bool {
d := make([]byte, 64)
copy(d[:32], ethutil.Encode(self.withoutNonce()))
binary.BigEndian.PutUint32(d[60:], self.Nonce)
return ethutil.FirstBitSet(ethutil.BigD(crypto.Sha3(d))) > 0
}
func (self *Envelope) withoutNonce() interface{} {
return []interface{}{self.Expiry, self.Ttl, ethutil.ByteSliceToInterface(self.Topics), self.Data}
}
func (self *Envelope) RlpData() interface{} {
return []interface{}{self.Expiry, self.Ttl, ethutil.ByteSliceToInterface(self.Topics), self.Data, self.Nonce}
}
|
