Homework on Bitcoin Transactions and UTXO - Questions

[Alex_Cheung]

1. UTXOs is input created from a previous transaction. It is the equivalent of the balance of the wallet.

2. If there are 0 UTXOs, then a transaction cannot be made.

3. A wallet specifies the transaction fee from the remainder of the inputs available in the UTXO and the output of a transaction. It is implied rather than specific as all UTXO needs to be spent, so the leftover will be sent back into the wallet. The leftover that gets sent back will be slightly less than the original input. That slightly less difference will be the transaction fee.

4.Inputs and outputs can be used to increase privacy in a transaction because the encryption that happens makes it so that that addresses the outputs go to are unknown, including the remaining inputs that get transferred back to the “original” wallet.

[jose_martin]

1. Unspent Transaction Outputs are outputs from a previous transaction that are available and have not been spent.
2. If you do not have any single UTXO large enough to cover your transaction then the transaction will be declined.
3. The bitcoin wallet specifies the transaction fee when creating a transaction by substracting the input from the output.
4. From the outside it is impossible to know which output went where, to the recipient, to the sender and there can be multiple outputs. That increases anonymity in transactions.

[TheCryptoRat]

1. Describe what Unspent Transaction Outputs (UTXO) are.
Outputs from other transactions that aren’t spent. When sending an output, the whole balance is sent as the output with the amount not being spent being sent back to the wallet

2. What would happen if you don’t have any single UTXO that is large enough to cover for your transaction?
Your transaction would be rejected and funds returned minus a small fee

3. How would a bitcoin wallet specify the transaction fee when creating a transaction?
It would give you an approximate fee needed for the transaction to be mined which will then be deducted from the utxo’s used for the transaction.

4. How could you use the notion of transaction inputs and outputs to increase privacy in your transaction?
If you create different addresses each time you do a transaction, all the bitcoin will be moved to that new address (minus the fee or payable amount). Since addresses are not linked to an identity it is hard to try to link utxo’s to an individual.

[alve_lagander]

1. A utxo is basically just btc that you haven’t spent yet.
2. The network redeems the transaction impossible and nothing happens.
3. Fee = input - output
4. Because the transaction’s participants are just encrypted addresses.

[Alko89]

@jose_martin

If you do not have any single UTXO large enough to cover your transaction then the transaction will be declined.

@TheCryptoRat

Your transaction would be rejected and funds returned minus a small fee

@alve_lagander

The network redeems the transaction impossible and nothing happens.

You can use multiple UTXOs as inputs to a new tx. If you still don’t have enough then your tx would be declined.

[Lexiih36]

Utxos are the transactions that have been sent to your private key. Basically your balance.
Would not be able to make a transaction without having enough utxos. you cant just suddenly generate a code from nothing
input-output
There is no way of knowing who made what transaction based off of just their public key. So no one can trace it to you, and you can spend your money however you want.

[DisenfranchisedSoul]

@ivan

• Describe what Unspent Transaction Outputs (UTXO) are.
• What would happen if you don’t have any single UTXO that is large enough to cover for your transaction?
• How would a bitcoin wallet specify the transaction fee when creating a transaction?
• How could you use the notion of transaction inputs and outputs to increase privacy in your transaction?

1. They are transactions that have been assigned to a ‘new’ owner but remain attached to the block chain until the new owner uses them.
2. It will deny the transaction
3. It subtracts the output from the inputs and the difference is the estimated transaction fee.
   4.You can send coin to yourself as well as others in the transaction and it muddies the chain that could be linked to you specifically.

[Alko89]

@DisenfranchisedSoul

It will deny the transaction

You can use multiple UTXOs as inputs to a new tx. If you still don’t have enough then your tx would be declined.

[jokir]

1. UTXO are unspent transactions that your wallet has access to. The total value of all UTXO assigned to you wallet is the total balance of all BTC your wallet has available to spend.

2. Transaction would be rejected if your wallet attempted to submit to blockchain.

3. Transaction fee is included in the total output and must be covered by the total inputs.

4. The inputs and outputs are anonymous addresses so it is unclear exactly where the money is going. Additionally, additional UTXOs could be added to the transaction to further obfuscate.

[erik_sonos]

1. They are outputs that are stored in your crypto wallet with which you make payments. UTXOs represent the total amount of BTC that you can spend.

2. The transaction would not go through, it’d be deemed invalid by the blockchain as it checks with your crypto wallet whether there are enough UTXOs.

3. Fee = Inputs - Outputs. Most crypto wallets calculate the fee automatically for you and let you know what the amount will be.

4. Create multiple output addresses. That will make it near impossible to trace back to your private key.

[DanDan]

1. Describe what Unspent Transaction Outputs (UTXO) are.
A UTXO is the output from a previous transaction that is yet to be placed into a new transaction as an input. Your entire wallet balance is made up of UTXO’s read by your wallet from the blockchain.
2. What would happen if you don’t have any single UTXO that is large enough to cover for your transaction?
Your wallet would use another UTXO combined with the first UTXO as inputs that together are a sum that is more than the transaction amount. Then within the outputs on the transaction, the amount left over after covering the transaction amount would then be sent back to your wallet as a new UTXO. The same as if you had used a £10 note to pay for a £5 transaction, you would get your £5 change in return.
3. How would a bitcoin wallet specify the transaction fee when creating a transaction?
It calculates this fee based on what it thinks will get your transaction into the blockchain fast enough, based on other transactions taking place on the blockchain and their average fees.
4. How could you use the notion of transaction inputs and outputs to increase privacy in your transaction?
Any individual can have multiple Bitcoin addresses and no one person can tell who those addresses belong to, therefore if an individual spreads out there BTC among multiple addresses then it is impossible to work out how much BTC they truly own based on TX data.

[Emmaculate]

1). Unspent transaction outputs , UTXOs, are transaction outputs from a sender to a receiver that are yet to be spent by the receiver.

2). In a situation where there’s no single transaction output large enough to cover for a transaction, Several UTXOs can be combined to create a single output. A portion of the excess goes to miners as transaction fees and the rest goes back to the change address in the sender’s wallet.

3). Transaction fees are rather implied when creating a transaction and it can be derived by subtracting the output from the input of a transaction. Fees = input - output

4). The notion of transaction inputs and outputs can be used to increase privacy in transactions by generating different addresses for different transactions. That way,no one but the private key owner is aware that all different transactions belong to him.

[Andreas_Langes]

1. UTXOs are the inputs that can be used for the transaction. The total UTXOs are the balance of the wallet.

2. Then multiple UTXOs (if there are) will be used to fill the transaction.

3. Fee = Input - Output

4. Part of the output goes back to you (in case you spend less than UTXOs present), which might be to a different address, but might be the same wallet. No one knows the private key owner.

[fakz]

1. (UTXO) is the total amount available in your wallet. They serve as the input for every transaction.

2. The transaction will be rejected.

3. The wallet will specify the transaction fee based on the traffic level in the blockchain and required speed of transaction.

[Roberto_Torrens]

1. UTXO unspent outputs of the previous transaction.
2. It will sum up more UTXOs if there is no sum , the transaction is invalid.
3. Input = Output + TX fee
4. Anonymity is provided by the nature of bitcoin transaction.

[Alko89]

@fakz

(UTXO) is the total amount available in your wallet. They serve as the input for every transaction.

The sum of all your UTXOs is your balance.

@jokir

Transaction would be rejected if your wallet attempted to submit to blockchain.

@fakz

The transaction will be rejected.

You can use multiple UTXOs as inputs to a new tx. If you still don’t have enough then your tx would be rejected.

[crypto-djent76]

Describe what Unspent Transaction Outputs (UTXO) are

Unspent Transaction Outputs (UTXOs) refer to the amount of digital currency someone has left remaining after executing a cryptocurrency transaction.

What would happen if you don’t have any single UTXO that is large enough to cover for your transaction?

If you don't have any single UTXO that is large enough to cover your transaction, then either the transaction will be disregarded or it will be combined with another UTXO that you own to make up the total transaction amount.

How would a bitcoin wallet specify the transaction fee when creating a transaction?

The transaction fee is calculated by subtracting the total transaction inputs by the total transaction outputs.

How could you use the notion of transaction inputs and outputs to increase privacy in your transaction?

By using several output addresses from a single transaction input, it causes an obfuscation on your identity or private key.

[themichaelbird]

1. they are outputs from someone else into your wallet for example. They are not considered spent until another transaction is created and sent as a new “output”. All of this is tracked on the block chain. your wallet is really reflecting UTXOs

2. you would give multiple and send the remainder to yourself

3. it will pick the fee that it thinks is best based on the previous fees to get you in the blockchain reasonably fast

4. you can increase privacy by sending utxo’s to another private address you have so there isn’t a way of confirming if it went back to you or someone else

[soshau01]

1. UTXO’s are the result of a transaction that has not been used for another transaction yet.
2. The wallet would group together different UTXO’s for that transaction and send you a new UTXO for the difference.
3. It doesn’t specify, it implies what it would be based on the difference of the input UTXO’s and the output UTXO’s. When the transaction is complete then you get the actual fee.
4. Buy just looking at the blockchain transactions it is impossible to see who those transactions actually belong to. Therefore they are unable to track where input and output’s go and come from.

[patricia2157]

1. It is the amount in digital eg. BTC that one can use in a new transaction/s. But the input has to equal the output.
2. If the output transaction is larger than the present UTXO then it can take place.
3. The wallet will calculate the fee based on present network conditions at that time and the data size of the transaction.
4. Not sure about this becos the wallet has the private key to facilitate the transaction and the actual transaction recording is done via the adding to the blockchain by the miners and it will amongst a lot of other transactions that the miners are adding into a block. It would be difficult to trace it backwards I would have thot. Maybe not impossible.