package ethchain import ( "github.com/ethereum/eth-go/ethutil" "github.com/obscuren/sha3" "hash" "log" "math/big" "math/rand" "time" ) type PoW interface { Search(block *Block) []byte Verify(hash []byte, diff *big.Int, nonce []byte) bool } type EasyPow struct { hash *big.Int } func (pow *EasyPow) Search(block *Block) []byte { r := rand.New(rand.NewSource(time.Now().UnixNano())) hash := block.HashNoNonce() diff := block.Difficulty for { sha := ethutil.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)) log.Printf("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)) }