Official Go implementation of the Ethereum protocol
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go-ethereum/ethchain/dagger.go

218 lines
4.1 KiB

package ethchain
import (
"github.com/ethereum/eth-go/ethcrypto"
"github.com/ethereum/eth-go/ethlog"
"github.com/ethereum/eth-go/ethreact"
"github.com/ethereum/eth-go/ethutil"
"github.com/obscuren/sha3"
"hash"
"math/big"
"math/rand"
"time"
)
var powlogger = ethlog.NewLogger("POW")
type PoW interface {
Search(block *Block, reactChan chan ethreact.Event) []byte
Verify(hash []byte, diff *big.Int, nonce []byte) bool
}
type EasyPow struct {
hash *big.Int
}
func (pow *EasyPow) Search(block *Block, reactChan chan ethreact.Event) []byte {
r := rand.New(rand.NewSource(time.Now().UnixNano()))
hash := block.HashNoNonce()
diff := block.Difficulty
i := int64(0)
start := time.Now().UnixNano()
for {
select {
case <-reactChan:
powlogger.Infoln("Breaking from mining")
return nil
default:
i++
if i%1234567 == 0 {
elapsed := time.Now().UnixNano() - start
hashes := ((float64(1e9) / float64(elapsed)) * float64(i)) / 1000
powlogger.Infoln("Hashing @", int64(hashes), "khash")
}
sha := ethcrypto.Sha3Bin(big.NewInt(r.Int63()).Bytes())
if pow.Verify(hash, diff, sha) {
return sha
}
}
}
return nil
}
func (pow *EasyPow) Verify(hash []byte, diff *big.Int, nonce []byte) bool {
sha := sha3.NewKeccak256()
d := append(hash, nonce...)
sha.Write(d)
v := ethutil.BigPow(2, 256)
ret := new(big.Int).Div(v, diff)
res := new(big.Int)
res.SetBytes(sha.Sum(nil))
return res.Cmp(ret) == -1
}
func (pow *EasyPow) SetHash(hash *big.Int) {
}
type Dagger struct {
hash *big.Int
xn *big.Int
}
var Found bool
func (dag *Dagger) Find(obj *big.Int, resChan chan int64) {
r := rand.New(rand.NewSource(time.Now().UnixNano()))
for i := 0; i < 1000; i++ {
rnd := r.Int63()
res := dag.Eval(big.NewInt(rnd))
powlogger.Infof("rnd %v\nres %v\nobj %v\n", rnd, res, obj)
if res.Cmp(obj) < 0 {
// Post back result on the channel
resChan <- rnd
// Notify other threads we've found a valid nonce
Found = true
}
// Break out if found
if Found {
break
}
}
resChan <- 0
}
func (dag *Dagger) Search(hash, diff *big.Int) *big.Int {
// TODO fix multi threading. Somehow it results in the wrong nonce
amountOfRoutines := 1
dag.hash = hash
obj := ethutil.BigPow(2, 256)
obj = obj.Div(obj, diff)
Found = false
resChan := make(chan int64, 3)
var res int64
for k := 0; k < amountOfRoutines; k++ {
go dag.Find(obj, resChan)
// Wait for each go routine to finish
}
for k := 0; k < amountOfRoutines; k++ {
// Get the result from the channel. 0 = quit
if r := <-resChan; r != 0 {
res = r
}
}
return big.NewInt(res)
}
func (dag *Dagger) Verify(hash, diff, nonce *big.Int) bool {
dag.hash = hash
obj := ethutil.BigPow(2, 256)
obj = obj.Div(obj, diff)
return dag.Eval(nonce).Cmp(obj) < 0
}
func DaggerVerify(hash, diff, nonce *big.Int) bool {
dagger := &Dagger{}
dagger.hash = hash
obj := ethutil.BigPow(2, 256)
obj = obj.Div(obj, diff)
return dagger.Eval(nonce).Cmp(obj) < 0
}
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 Sum(sha hash.Hash) []byte {
//in := make([]byte, 32)
return sha.Sum(nil)
}
func (dag *Dagger) Eval(N *big.Int) *big.Int {
pow := ethutil.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))
}