基礎資料

發行總量：2100萬。
新區塊生成周期：約10分鐘。
挖礦難度調整週期：每2016個區塊，大約2個星期。
挖礦獎勵：比特幣的挖礦獎勵來源於兩部分：

• 創世區塊獎勵50個比特幣，以後每210000個區塊減半，即約4年調整一次。目前已經經歷了兩次減半，當前的挖礦獎勵為12.5個比特幣。
• 比特幣的每個交易必須支付一定數額的手續費給礦工。這個設定是為了防止惡意節點發送大量的垃圾交易對比特幣網路進行DOS攻擊。

挖礦演算法

挖礦參考演算法：挖礦演算法為SHA256。在挖礦過程中，礦工將比特幣的80個位元組長度的區塊頭資料進行兩次SHA256運算，運算結果就是一個256位（32位元組）長度的字串。通過比較與當前難度值的大小判斷當前區塊是否合法。即滿足下列條件：
SHA256(SHA256(block_header))< difficulty

例項分析

為了更加深入理解比特幣的挖礦演算法，以一個實際的區塊資料為例。

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
 
988ac0000000001000000010b6072b386d4a773235237f64c1126ac3b240c84b917a3909ba1c43ded5f51f4000000008c493046022100bb1ad26df930a51cce110cf44f7a48c3c561fd977500b1ae5d6b6fd13d0b3f4a022100c5b42951acedff14abba2736fd574bdb465f3e6f8da12e2c5303954aca7f78f3014104a7135bfe824c97ecc01ec7d7e336185c81e2aa2c41ab175407c09484ce9694b44953fcb751206564a9c24dd094d42fdbfdd5aad3e063ce6af4cfaaea4ea14fbbffffffff0140420f00000000001976a91439aa3d569e06a1d7926dc4be1193c99bf2eb9ee088ac00000000
 

獲取的資料是16進位制的，其中前80個位元組是區塊頭資料。對前80個位元組資料進行雙SHA256運算，得到當前區塊的雜湊值。Go語言程式碼如下：

package main

import (
    "crypto/sha256"
    "encoding/hex"
    "fmt"
)

const HashSize = 32
type Hash [32]byte

func (hash Hash) String() string {
    for i := 0; i < HashSize/2; i++ {
        hash[i], hash[HashSize-1-i] = hash[HashSize-1-i], hash[i]
    }
    return hex.EncodeToString(hash[:])
}

func main() {
    block, _ := hex.DecodeString("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")
    first := sha256.Sum256(block[:80])  // 選擇區塊的前80個位元組，即區塊頭資料，進行第一次雜湊運算
    second := sha256.Sum256(first[:])   // 將第一次結果繼續雜湊，得到第二個結果，該結果為區塊雜湊值
    fmt.Printf("blockheader is: \n%x\n", block[:80])
    fmt.Printf("doublehash is:\n%v\n", Hash(second))
}

執行結果為：

blockheader is:
0100000050120119172a610421a6c3011dd330d9df07b63616c2cc1f1cd00200000000006657a9252aacd5c0b2940996ecff952228c3067cc38d4885efb5a4ac4247e9f337221b4d4c86041b0f2b5710
doublehash is:
000000000003ba27aa200b1cecaad478d2b00432346c3f1f3986da1afd33e506

可以發現經過兩次SHA256運算之後得到的結果就是區塊雜湊。