The Path of a Single Bitcoin from “Send” to “Received”

In this video I want to tie everything up and explain how a Bitcoin travels from the moment it is sent, up until its recipient receives it. If you haven’t watched the previous tutorials I recommend starting from there as this video may use some unfamiliar terminology.

To begin with, let’s talk about Bitcoin nodes. Nodes are just computers which are connected to the Internet and hold a complete copy of the Blockchain. If you have a Bitcoin wallet on your computer, you’re probably a node yourself.

Now let’s say I want to send you 1 Bitcoin. I log into my Bitcoin wallet, enter your public address as the recipient and hit “send”.

Once I click “send”, my wallet will use my private key and transaction message to create a unique digital signature for this transaction. The wallet will then group this signature along with my transaction message into of a file. This file will be shared with nodes around the network that will verify its validity using only my public key. If something doesn’t add up they will reject it and stop sharing it.

At this point you will see the transaction on your wallet as “unconfirmed”. Even though the transaction is valid, it’s considered unconfirmed or “unordered” since it’s just floating around the network.

Miners will gather this floating transaction file along with other unconfirmed files like it, and will need to order them in some way. This is important in order to prevent double spending as explained in previous videos.

First the miners will group transactions together into what is know as a block. Afterward, they will try to get the new block into the Blockchain. Miners will use their super powerful computers to solve a mathematical problem; the first miner to succeed in this will get his block into the Blockchain and receive a bounty. At this point the transaction will have 1 confirmation.

So blocks are ordered one after the other dictating the exact transaction order – hence the name Blockchain.

Over time other blocks will be built over the block containing our transaction. The more blocks built the more confirmations you will see, and the risk of me succeeding in double spending this Bitcoin will reduce.

Congratulations…you are now Bitcoin certified.

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Anonymous
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Anonymous

I have accidentally bought way too many bitcoins than I am allowed, will this transaction go through?

Rob Esmund
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Rob Esmund

If a transaction remains unconfirmed for three days does it mean something is wtrong and it will never be cleared or completed? In which case can it be reversed?
Or is it that there is congestion in the blockchain and every transaction wioll eventually be cleared?

Samuel
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Samuel

Thanks a lot for these lessons. Very informative. Please continue and give us more.

Ramani
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Ramani

Hi Ofir, The free BTC that you gave me as part of the sign up has 75 confirmations? 1. Why does a transaction need to be confirmed so many times? 2. What does the current miner do, that the previous miner did not do in their process? 3. What determines a transaction “confirmed”? Previous Videos 4: What is the rationale behind 1. Saying the total BTC available for mint is only 21 million? Why not more ?Why not less? 2. Satoshi not allowing to mint new BTC? 3. Satoshi’s rationale to maintain the minted BTC to 0 regardless of how… Read more »