>[success] # 一条简单的区块链 >[info] ### 区块 - 区块链首先要有区块, 区块里存放着交易相关等数据 - 在本节中我们弄一个简单的区块, 仅仅包含最关键的信息，其数据结构在go语言定义如下： ```go type Block struct { Timestamp int64 //时间戳 Data []byte //内容 PrevBlockHash []byte //上一个区块的Hash Hash []byte //当前区块的Hash } ``` - 其中Hash计算如下 ```go Hash = SHA256(PrevBlockHash + Timestamp + Data) ``` >[info] ### 区块链 - 将一个个区块连接起来组成区块链 ```go type Blockchain struct { blocks []*Block //区块的切片即区块链 } ``` >[warning] ### 一条简单的区块链 - 通过区块和区块链实现一条简单的区块链 ```go package main import ( "bytes" "crypto/sha256" "fmt" "strconv" "time" ) //区块 type Block struct { Timestamp int64 PrevBlockHash []byte Hash []byte Data []byte } //区块链 type BlockChain struct { blocks []*Block } func main() { // 创建一个有创世块的链 blockchain := NewBlockChain() //添加新的块 blockchain.AddBlock("第二个块的内容") blockchain.AddBlock("第三个块的内容") //遍历块 for _, block := range blockchain.blocks { fmt.Printf("Timestamp: %s\n", time.Unix(block.Timestamp, 0).Format("2006-01-02 03:04:05")) fmt.Printf("Prev hash: %x\n", block.PrevBlockHash) fmt.Printf("Data: %s\n", block.Data) fmt.Printf("Hash: %x\n", block.Hash) fmt.Println() } } func NewBlock(data string, prevBlockHash []byte) *Block { block := &Block{ Timestamp: time.Now().Unix(), PrevBlockHash: prevBlockHash, Data: []byte(data), Hash: []byte{}, } //设置当前块Hash block.SetHash() return block } // Hash = sha256(PrevBlockHash + Data + Timestamp) func (b *Block) SetHash() { timestamp := []byte(strconv.FormatInt(b.Timestamp, 10)) headers := bytes.Join([][]byte{b.PrevBlockHash, b.Data, timestamp}, []byte{}) hash := sha256.Sum256(headers) b.Hash = hash[:] } //创世块 func NewGenesisBlock() *Block { return NewBlock("创世块", []byte{}) } //创世链 func NewBlockChain() *BlockChain { return &BlockChain{[]*Block{NewGenesisBlock()}} } //添加块 func (blockchain *BlockChain) AddBlock(data string) { prevBlock := blockchain.blocks[len(blockchain.blocks)-1] //获取上一个区块的Hash newBlock := NewBlock(data, prevBlock.Hash) blockchain.blocks = append(blockchain.blocks, newBlock) //把当前块添加到区块链上 } ``` >[danger] ### 效果图 ``` Timestamp: 2020-01-07 17:14:43 Prev hash: Data: 创世块 Hash: cf774fdc758cbb90e28cf053401927576a7350f778b60631112ce6fc074a278a Timestamp: 2020-01-07 17:14:43 Prev hash: cf774fdc758cbb90e28cf053401927576a7350f778b60631112ce6fc074a278a Data: 第二个块的内容 Hash: 3dd326874c10708e299c649760ed93689670a0d4fbeecd0a20755e0cbc9aded1 Timestamp: 2020-01-07 17:14:43 Prev hash: 3dd326874c10708e299c649760ed93689670a0d4fbeecd0a20755e0cbc9aded1 Data: 第三个块的内容 Hash: 5a2aaa1c443453717cbb92a85893c9600e2166555428a1d5714bf742842bb6cd ```