go-ethereum/dagger.go

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package main
import (
"math/big"
"math/rand"
"time"
"github.com/obscuren/sha3"
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"hash"
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)
type Dagger struct {
hash *big.Int
xn *big.Int
}
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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()
if dag.Eval(big.NewInt(rnd)).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 {
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// TODO fix multi threading. Somehow it results in the wrong nonce
amountOfRoutines := 1
dag.hash = hash
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obj := BigPow(2, 256)
obj = obj.Div(obj, diff)
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Found = false
resChan := make(chan int64, 3)
var res int64
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for k := 0; k < amountOfRoutines; k++ {
go dag.Find(obj, resChan)
}
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// 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
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}
}
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return big.NewInt(res)
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}
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func DaggerVerify(hash, diff, nonce *big.Int) bool {
dagger := &Dagger{}
dagger.hash = hash
obj := BigPow(2, 256)
obj = obj.Div(obj, diff)
return dagger.Eval(nonce).Cmp(obj) < 0
}
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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.NewKeccak224()
sha.Reset()
d := sha3.NewKeccak224()
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())
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b.SetBytes(Sum(d))
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pk := b.Uint64() & ((1 << ((L - 1) * 3)) - 1)
sha.Write(dag.Node(L - 1, pk).Bytes())
}
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ret.SetBytes(Sum(sha))
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return ret
}
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func Sum(sha hash.Hash) []byte {
in := make([]byte, 32)
return sha.Sum(in)
}
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func (dag *Dagger) Eval(N *big.Int) *big.Int {
pow := BigPow(2, 26)
dag.xn = N.Div(N, pow)
sha := sha3.NewKeccak224()
sha.Reset()
ret := new(big.Int)
for k := 0; k < 4; k++ {
d := sha3.NewKeccak224()
b := new(big.Int)
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d.Reset()
d.Write(dag.hash.Bytes())
d.Write(dag.xn.Bytes())
d.Write(N.Bytes())
d.Write(big.NewInt(int64(k)).Bytes())
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b.SetBytes(Sum(d))
pk := (b.Uint64() & 0x1ffffff)
sha.Write(dag.Node(9, pk).Bytes())
}
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return ret.SetBytes(Sum(sha))
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}