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|
package main
import (
"bytes"
"encoding/binary"
"log"
"fmt"
"encoding/hex"
"crypto/sha256"
"strconv"
"math"
"math/big"
)
var (
maxnonce int32 = math.MaxInt32
)
type Block struct{
version int32
prevBlockHash []byte
merkleroot [] byte
hash []byte
time int32
bits int32
nonce int32
}
func IntToHex(num int32) []byte{
buff := new(bytes.Buffer)
err:= binary.Write(buff,binary.LittleEndian,num)
if err!=nil{
log.Panic(err)
}
return buff.Bytes()
}
func IntToHex2(num int32) []byte{
buff := new(bytes.Buffer)
err:= binary.Write(buff,binary.BigEndian,num)
if err!=nil{
log.Panic(err)
}
return buff.Bytes()
}
func ReverseBytes4(data []byte){
for i,j :=0,len(data) - 1;i<j;i,j = i+1,j - 1{
data[i],data[j] = data[j],data[i]
}
}
func (block *Block) serialize() []byte{
result := bytes.Join(
[][]byte{
IntToHex(block.version),
block.prevBlockHash,
block.merkleroot,
IntToHex(block.time),
IntToHex(block.bits),
IntToHex(block.nonce)},
[]byte{},
)
return result
}
func main(){
prev,_ := hex.DecodeString("000000000000000016145aa12fa7e81a304c38aec3d7c5208f1d33b587f966a6")
ReverseBytes4(prev)
fmt.Printf("%x\n",prev)
merkleroot,_ := hex.DecodeString("3a4f410269fcc4c7885770bc8841ce6781f15dd304ae5d2770fc93a21dbd70d7")
ReverseBytes4(merkleroot)
fmt.Printf("%x\n",merkleroot)
block := &Block{
2,
prev,
merkleroot,
[]byte{},
1418755780,
404454260,
0,
}
targetHash:=CalculateTargetFast(IntToHex2(block.bits))
var tartget big.Int
tartget.SetBytes(targetHash)
var currenthash big.Int
for block.nonce < maxnonce{
data:= block.serialize()
fitstHash := sha256.Sum256(data)
secondhash := sha256.Sum256(fitstHash[:])
ReverseBytes4(secondhash[:])
fmt.Printf("nonce:%d, currenthash:%x\n",block.nonce,secondhash)
currenthash.SetBytes(secondhash[:])
if currenthash.Cmp(&tartget) == -1{
break
}else{
block.nonce++
}
}
}
func CalculateTargetFast(bits []byte) []byte{
var result []byte
exponent := bits[:1]
fmt.Printf("%x\n",exponent)
coeffient:= bits[1:]
fmt.Printf("%x\n",coeffient)
str:= hex.EncodeToString(exponent)
fmt.Printf("str=%s\n",str)
exp,_:=strconv.ParseInt(str,16,8)
fmt.Printf("exp=%d\n",exp)
result = append(bytes.Repeat([]byte{0x00},32-int(exp)),coeffient...)
result = append(result,bytes.Repeat([]byte{0x00},32-len(result))...)
return result
}
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