Initial commit

chain/block.go

@@ -0,0 +1,79 @@
+package chain
+
+import (
+	"bytes"
+	"encoding/gob"
+	"fmt"
+	"golang.org/x/crypto/sha3"
+	"log"
+	"math/rand"
+)
+
+type block struct {
+	Transactions []transaction
+	HashPrevious []byte
+	Nonce        []byte
+}
+
+func NewBlock(hashPrevious []byte) block {
+	return block{
+		Transactions: nil,
+		HashPrevious: hashPrevious,
+	}
+}
+
+func (b *block) AddTransaction(t transaction) {
+	b.Transactions = append(b.Transactions, t)
+}
+
+func (b block) GenerateHash(difficulty int) []byte {
+	found := false
+	var compBytes []byte
+	for i := 0; i < difficulty; i++ {
+		compBytes = append(compBytes, []byte("0x00")...)
+	}
+	for !found {
+		random := make([]byte, 64)
+		rand.Read(random)
+		b.Nonce = random
+		var buf bytes.Buffer
+		err := gob.NewEncoder(&buf).Encode(b.Nonce)
+		if err != nil {
+			log.Fatal(err)
+		}
+		hasher := sha3.New512()
+		hasher.Write(b.ToBytes())
+		hash := hasher.Sum(nil)
+		fmt.Printf("\033[2K\r%x\n", hash)
+		if checkAllZero(XorSlice(hash[:difficulty], compBytes)) {
+			return hash
+		}
+	}
+	return nil
+}
+
+func (b block) ToBytes() []byte {
+	var bytes []byte
+	for i := 0; i < len(b.Transactions); i++ {
+		bytes = append(bytes, b.Transactions[i].ToBytes()...)
+	}
+	bytes = append(bytes, b.Nonce...)
+	return bytes
+}
+
+func XorSlice(a []byte, b []byte) []byte {
+	for i, _ := range a {
+		a[i] = a[i] ^ b[i]
+	}
+	return a
+}
+
+func checkAllZero(a []byte) bool {
+	fmt.Printf("Checking if all zero: %x\n", a)
+	for i, _ := range a {
+		if a[i] != 0x00 {
+			return false
+		}
+	}
+	return true
+}