自从比特币火起来以后,网上对比特币的解释可谓汗牛充栋,纷繁复杂。但对于程序员来说,最直接的方式莫过于直接看程序代码了。嫌比特币代码庞杂没关系,我找到一段简明扼要的代码,用来理解比特币再好不过了。
以下这段程序转自知乎上Wu Hao的回答。
- function mine()
- {
- while(true)
- {
- longestChain = getLongestValidChain()
- -- A number that changes every time, so that you don't waste
- -- time trying to calculate a valid blockHash with the same
- -- input.
- nonce = getNewNonce()
- currentTXs = getUnconfirmedTransactionsFromNetwork()
- newBlock = getNewBlock(longestChain, currentTXs, nonce)
- -- http://en.wikipedia.org/wiki/SHA-2
- -- and this is what all the "mining machines" are doing.
- blockHash = sha256(newBlock)
- if (meetReqirements(blockHash))
- {
- broadcast(newBlock)
- -- Now the height the block chain is incremented by 1
- -- (if the new block is accepted by other peers),
- -- and all the TXs in the new block are "confirmed"
- }
- }
- }
- ////////////////////////////////////////////////////////////////
- function sendBTC(amount)
- {
- sourceTXs = pickConfirmedTransactionsToBeSpent(amount)
- tx = generateTX(sourceTXs, targetAddrs, amount, fee)
- signedTx = sign(tx, privateKeysOfAllInputAddress)
- broadcast(signedTx)
- }
- ////////////////////////////////////////////////////////////////
下面是我的解释:
挖矿过程就是不断从比特币网络中获取所有未确认交易getUnconfirmedTransactionsFromNetwork(),把它们打包成一个区块并挂载目前最长的区块链上getNewBlock(longestChain, currentTXs, nonce),然后计算新的区块的散列值sha256(newBlock),如果散列值正好满足挖矿难度了meetReqirements(blockHash),那么就挖矿成功了。所谓挖矿难度,指的是要求的二进制散列值末尾0的个数,而散列值是碰运气生成的,除了穷举没有别的办法,要求的0个数越多挖矿的难度就越大。
付款过程就是把一些有余额的已确认交易拿出来作为发送地址pickConfirmedTransactionsToBeSpent(amount),然后根据目标地址支付一定交易费生成新的交易generateTX(sourceTXs, targetAddrs, amount, fee),并用钱包私钥对交易签名sign(tx, privateKeysOfAllInputAddress),然后广播出去。
原文链接:https://www.byvoid.com/zhs/blog/bitcoin-principle-program