mirror of https://github.com/poanetwork/quorum.git
111 lines
2.0 KiB
Go
111 lines
2.0 KiB
Go
package main
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import (
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"math/big"
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"fmt"
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"math/rand"
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"time"
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"github.com/obscuren/sha3"
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)
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type Dagger struct {
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hash *big.Int
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xn *big.Int
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}
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func (dag *Dagger) Search(diff *big.Int) *big.Int {
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dag.hash = big.NewInt(0)
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obj := BigPow(2, 256)
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obj = obj.Div(obj, diff)
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fmt.Println("diff", diff, "< objective", obj)
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r := rand.New(rand.NewSource(time.Now().UnixNano()))
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rnd := big.NewInt(r.Int63())
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fmt.Println("init rnd =", rnd)
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for i := 0; i < 1000; i++ {
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if dag.Eval(rnd).Cmp(obj) < 0 {
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fmt.Println("Found result! i = ", i)
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return rnd
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}
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rnd = rnd.Add(rnd, big.NewInt(1))
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}
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return big.NewInt(0)
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}
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func (dag *Dagger) Node(L uint64, i uint64) *big.Int {
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if L == i {
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return dag.hash
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}
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var m *big.Int
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if L == 9 {
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m = big.NewInt(16)
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} else {
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m = big.NewInt(3)
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}
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sha := sha3.NewKeccak224()
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sha.Reset()
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d := sha3.NewKeccak224()
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b := new(big.Int)
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ret := new(big.Int)
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for k := 0; k < int(m.Uint64()); k++ {
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d.Reset()
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d.Write(dag.hash.Bytes())
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d.Write(dag.xn.Bytes())
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d.Write(big.NewInt(int64(L)).Bytes())
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d.Write(big.NewInt(int64(i)).Bytes())
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d.Write(big.NewInt(int64(k)).Bytes())
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b.SetBytes(d.Sum(nil))
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pk := b.Uint64() & ((1 << ((L - 1) * 3)) - 1)
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sha.Write(dag.Node(L - 1, pk).Bytes())
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}
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ret.SetBytes(sha.Sum(nil))
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return ret
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}
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func (dag *Dagger) Eval(N *big.Int) *big.Int {
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pow := BigPow(2, 26)
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dag.xn = N.Div(N, pow)
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sha := sha3.NewKeccak224()
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sha.Reset()
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ret := new(big.Int)
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doneChan := make(chan bool, 3)
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for k := 0; k < 4; k++ {
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go func(_k int) {
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d := sha3.NewKeccak224()
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b := new(big.Int)
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d.Reset()
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d.Write(dag.hash.Bytes())
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d.Write(dag.xn.Bytes())
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d.Write(N.Bytes())
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d.Write(big.NewInt(int64(_k)).Bytes())
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b.SetBytes(d.Sum(nil))
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pk := (b.Uint64() & 0x1ffffff)
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sha.Write(dag.Node(9, pk).Bytes())
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doneChan <- true
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}(k)
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}
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for k := 0; k < 4; k++ {
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<- doneChan
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}
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return ret.SetBytes(sha.Sum(nil))
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}
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