Implemented AR PoW

pow/ar/block.go

@@ -0,0 +1,11 @@
+package ar
+
+import (
+	"math/big"
+	"github.com/ethereum/eth-go/ethtrie"
+)
+
+type Block interface {
+	Trie() *ethtrie.Trie
+	Diff() *big.Int
+}

pow/ar/ops.go

@@ -0,0 +1,54 @@
+package ar
+
+import "math/big"
+
+const lenops int64 = 9
+
+type OpsFunc func(a, b *big.Int) *big.Int
+
+var ops [lenops]OpsFunc
+
+func init() {
+	ops[0] = Add
+	ops[1] = Mul
+	ops[2] = Mod
+	ops[3] = Xor
+	ops[4] = And
+	ops[5] = Or
+	ops[6] = Sub1
+	ops[7] = XorSub
+	ops[8] = Rsh
+}
+
+func Add(x, y *big.Int) *big.Int {
+	return new(big.Int).Add(x, y)
+}
+func Mul(x, y *big.Int) *big.Int {
+	return new(big.Int).Mul(x, y)
+}
+func Mod(x, y *big.Int) *big.Int {
+	return new(big.Int).Mod(x, y)
+}
+func Xor(x, y *big.Int) *big.Int {
+	return new(big.Int).Xor(x, y)
+}
+func And(x, y *big.Int) *big.Int {
+	return new(big.Int).And(x, y)
+}
+func Or(x, y *big.Int) *big.Int {
+	return new(big.Int).Or(x, y)
+}
+func Sub1(x, y *big.Int) *big.Int {
+	a := big.NewInt(-1)
+	a.Sub(a, x)
+
+	return a
+}
+func XorSub(x, y *big.Int) *big.Int {
+	t := Sub1(x, nil)
+
+	return t.Xor(t, y)
+}
+func Rsh(x, y *big.Int) *big.Int {
+	return new(big.Int).Rsh(x, uint(y.Uint64()%64))
+}

pow/ar/pow.go

@@ -0,0 +1,122 @@
+package ar
+
+import (
+	"math/big"
+
+	"github.com/ethereum/eth-go/ethutil"
+)
+
+type Entry struct {
+	op   OpsFunc
+	i, j *big.Int
+}
+
+type Tape struct {
+	tape  []Entry
+	block Block
+}
+
+func NewTape(block Block) *Tape {
+	return &Tape{nil, block}
+}
+
+func (self *Tape) gen(w, h int64, gen NumberGenerator) {
+	self.tape = nil
+
+	for v := int64(0); v < h; v++ {
+		op := ops[gen.rand64(lenops).Int64()]
+		r := gen.rand64(100).Uint64()
+
+		var j *big.Int
+		if r < 20 && v > 20 {
+			j = self.tape[len(self.tape)-1].i
+		} else {
+			j = gen.rand64(w)
+		}
+
+		i := gen.rand64(w)
+		self.tape = append(self.tape, Entry{op, i, j})
+	}
+}
+
+func (self *Tape) runTape(w, h int64, gen NumberGenerator) *big.Int {
+	var mem []*big.Int
+	for i := int64(0); i < w; i++ {
+		mem = append(mem, gen.rand(ethutil.BigPow(2, 64)))
+	}
+
+	set := func(i, j int) Entry {
+		entry := self.tape[i*100+j]
+		mem[entry.i.Uint64()] = entry.op(entry.i, entry.j)
+
+		return entry
+	}
+
+	dir := true
+	for i := 0; i < int(h)/100; i++ {
+		var entry Entry
+		if dir {
+			for j := 0; j < 100; j++ {
+				entry = set(i, j)
+			}
+		} else {
+			for j := 99; i >= 0; j-- {
+				entry = set(i, j)
+			}
+		}
+
+		t := mem[entry.i.Uint64()]
+		if big.NewInt(2).Cmp(new(big.Int).Mod(t, big.NewInt(37))) < 0 {
+			dir = !dir
+		}
+	}
+
+	return Sha3(mem)
+}
+
+func (self *Tape) Verify(header, nonce []byte) bool {
+	n := ethutil.BigD(nonce)
+
+	var w int64 = 10000
+	var h int64 = 150000
+	gen := Rnd(Sha3([]interface{}{header, new(big.Int).Div(n, big.NewInt(1000))}))
+	self.gen(w, h, gen)
+
+	gen = Rnd(Sha3([]interface{}{header, new(big.Int).Mod(n, big.NewInt(1000))}))
+	hash := self.runTape(w, h, gen)
+
+	it := self.block.Trie().Iterator()
+	next := it.Next(string(new(big.Int).Mod(hash, ethutil.BigPow(2, 160)).Bytes()))
+
+	req := ethutil.BigPow(2, 256)
+	req.Div(req, self.block.Diff())
+	return Sha3([]interface{}{hash, next}).Cmp(req) < 0
+}
+
+func (self *Tape) Run(header []byte) []byte {
+	nonce := big.NewInt(0)
+	var w int64 = 10000
+	var h int64 = 150000
+
+	req := ethutil.BigPow(2, 256)
+	req.Div(req, self.block.Diff())
+
+	for {
+		if new(big.Int).Mod(nonce, b(1000)).Cmp(b(0)) == 0 {
+			gen := Rnd(Sha3([]interface{}{header, new(big.Int).Div(nonce, big.NewInt(1000))}))
+			self.gen(w, h, gen)
+		}
+
+		gen := Rnd(Sha3([]interface{}{header, new(big.Int).Mod(nonce, big.NewInt(1000))}))
+		hash := self.runTape(w, h, gen)
+
+		it := self.block.Trie().Iterator()
+		next := it.Next(string(new(big.Int).Mod(hash, ethutil.BigPow(2, 160)).Bytes()))
+
+		if Sha3([]interface{}{hash, next}).Cmp(req) < 0 {
+			return nonce.Bytes()
+		} else {
+			nonce.Add(nonce, ethutil.Big1)
+		}
+	}
+}

pow/ar/pow_test.go

@@ -0,0 +1,47 @@
+package ar
+
+import (
+	"fmt"
+	"math/big"
+	"testing"
+
+	"github.com/ethereum/eth-go/ethdb"
+	"github.com/ethereum/eth-go/ethtrie"
+)
+
+type TestBlock struct {
+	trie *ethtrie.Trie
+}
+
+func NewTestBlock() *TestBlock {
+	db, _ := ethdb.NewMemDatabase()
+	return &TestBlock{
+		trie: ethtrie.New(db, ""),
+	}
+}
+
+func (self *TestBlock) Diff() *big.Int {
+	return b(10)
+}
+
+func (self *TestBlock) Trie() *ethtrie.Trie {
+	return self.trie
+}
+
+func (self *TestBlock) Hash() []byte {
+	a := make([]byte, 32)
+	a[0] = 10
+	a[1] = 2
+	return a
+}
+
+func TestPow(t *testing.T) {
+	entry := make([]byte, 32)
+	entry[0] = 255
+
+	block := NewTestBlock()
+
+	pow := NewTape(block)
+	nonce := pow.Run(block.Hash())
+	fmt.Println("Found nonce", nonce)
+}

pow/ar/rnd.go

@@ -0,0 +1,66 @@
+package ar
+
+import (
+	"math/big"
+
+	"github.com/ethereum/eth-go/ethcrypto"
+	"github.com/ethereum/eth-go/ethutil"
+)
+
+var b = big.NewInt
+
+type Node interface {
+	Big() *big.Int
+}
+
+type ByteNode []byte
+
+func (self ByteNode) Big() *big.Int {
+	return ethutil.BigD(ethutil.Encode([]byte(self)))
+}
+
+func Sha3(v interface{}) *big.Int {
+	if b, ok := v.(*big.Int); ok {
+		return ethutil.BigD(ethcrypto.Sha3(b.Bytes()))
+	} else if b, ok := v.([]interface{}); ok {
+		return ethutil.BigD(ethcrypto.Sha3(ethutil.Encode(b)))
+	} else if s, ok := v.([]*big.Int); ok {
+		v := make([]interface{}, len(s))
+		for i, b := range s {
+			v[i] = b
+		}
+
+		return ethutil.BigD(ethcrypto.Sha3(ethutil.Encode(v)))
+	}
+
+	return nil
+}
+
+type NumberGenerator interface {
+	rand(r *big.Int) *big.Int
+	rand64(r int64) *big.Int
+}
+
+type rnd struct {
+	seed *big.Int
+}
+
+func Rnd(s *big.Int) rnd {
+	return rnd{s}
+}
+
+func (self rnd) rand(r *big.Int) *big.Int {
+	o := b(0).Mod(self.seed, r)
+
+	self.seed.Div(self.seed, r)
+
+	if self.seed.Cmp(ethutil.BigPow(2, 64)) < 0 {
+		self.seed = Sha3(self.seed)
+	}
+
+	return o
+}
+
+func (self rnd) rand64(r int64) *big.Int {
+	return self.rand(b(r))
+}