Topic: How to determine the antiquity of my coins? (Read 1529 times)

You're welcome.


Transaction validity further highlights the fees issue.  Consider a coinbase transaction with a total output of, say, 25.3 BTC.  To be valid, we need that the total of all the fees of the transactions included in the block is at least 0.3 BTC.  To check this we'd need to check a large number of seemingly unrelated transactions.  Working recursively, we'd soon find ourselves checking transactions from 2010 if not 2009.

Also, you may have noticed that neither shorena nor I have yet used the term "address".  Bitcoin addresses don't really exist at the protocol level and are more of a higher-order convenience.  At any moment in time, an address could be associated with any number of different unspent transaction outputs.  The validity of a transaction which spends the balance of an address relies on the validity of each of these outputs.  The "antiquity" of a heavily used address, as you've described the term, will rise and fall with time as the set of unspent outputs it is associated with changes.

If anything, the "antiquity of an address" should probably correspond to the minimum of the numbers of the blocks in which it appears.

Thanks for your kindly explanations!

There's something I don't understand however, let's assume that a bitcoin address makes a valid transaction that spend all of this balance, while checking the validity of that transaction you have to go back in time, in transactions and in blocks.

I know now that the antiquity of particular coins can't be determined (thanks!), but antiquity of an address is just how much blocks you had to analyze to tell that the transaction is ok. Isn't?

As shorena puts across well and in detail, the question "When were my bitcoins born?" suggests an unfortunately common misunderstanding of how Bitcoin works. *

However, let's put this to one side and try to capture the spirit of your idea.  We'll say that an output y is a parent to an output x if there exists a transaction with y used as an input and x given as an output.  We'll say that an output y is an ancestor of an output x if there exists a chain of parents connecting x to y.  Finally, we'll define the bloodline birthblock of an output x to be the minimum of the heights of all blocks that contain ancestors of x. **

Given these definitions, every output has a well-defined bloodline birthblock and this concept corresponds loosely with "antiquity of my coins".  One could associate this concept with the chunk of bitcoin one imagines is stored in an output.  Following the analogy, Bitcoin transactions aren't so much moving chunks of bitcoin as they are breeding them (corresponding to the second shorena interpretation).

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* People like to think that chunks of bitcoin have identities independently of transactions and therefore can be tracked as they "move" through the blockchain.  In reality, a chunk of bitcoin is nothing more than a property of some Bitcoin output; an amount.

** For simplicity I have ignored fees, essentially assuming that fees are destroyed and created anew as they are claimed with coinbase transactions (corresponding to the first shorena interpretation).

You can follow a transaction chain back in time to its origin, but the coins you currently hold in your wallet either do not exist at all or were created when you received the transaction for them. Depends on your interpretation

Maybe a few examples can help.

Lets say you have received 1 BTC from A and 1 BTC from B. Your balance is 2 BTC.

If you want to spend 0.5 BTC you either use the coins you received from A the coins you received from B or both.

Lets assume you use the coins from A (or B). You send 0.5 to someone else and 0.5 (no fee for simplicity) back to yourself. These 0.5 you send back to yourself (called change) did not exist before. You just created them with your transaction. You can clearly say them came from A though.

Lets assume you use both coins from A and B. You send 1 BTC to someone else and 1 BTC back to yourself. Its impossible to say which coins come from A and which from B. You can follow both paths back and will probably find several coinbases where the coins originally came from.

Alternativly you can see bitcoin as a long chain of transactions (starting with the 1st coinbase transaction in each block) that can be referenced to create new transactions. This is closer to how bitcoin actually works, but more difficult to grasp for us humans. In this interpretation there are no coins[1].


[1] Feel free to use the "there is no spoon" kid voice in your head.

Hi there Bitcoin Society!

I was wondering when my Bitcoins were born, in which block height my coins were actually mined. There is a magical thing in think that maybe you have some Satoshis built in the first mountains of the Bitcoin blockchain.

There's no web-service/app for this? The idea is to search for a public address and obtain a detailed tree of coins movements up to the Coinbase.