How to make transaction id unique?

[guihao-liang]

I'm reading part 4, and I think if txid is not unique for this tutorial. Txid should be unique for blockchain. Otherwise, you can't lookup each transaction by txid.

The logic to generate txid. It generates the same id for newly mined coin:

https://github.com/Jeiwan/blockchain_go/blob/e17722eb18caa7618dee298da677a9f5667a0513/transaction.go#L64-L72

the FindUnspentTransactions would go wrong:

https://github.com/Jeiwan/blockchain_go/blob/e17722eb18caa7618dee298da677a9f5667a0513/blockchain.go#L78-L82

for example, could you mine 2 new coins with duplicated txid by calling NewCoinbaseTX("same_miner", "")

Then one coin could be used and the other is not. The above FindUnspentTransactions logic can't distinguish those 2 coins.

Even if you add rand in part 6, it still has a chance of colliding.

https://github.com/Jeiwan/blockchain_go/blob/0538111918aad7d18f2b71b19f8ad0dec186e6db/transaction.go#L174-L188

Any suggestion to make sure that the txid is unique?

[Anmilover]

您好，邮件已查收。Anmi、