Homework on Bitcoin Transactions and UTXO - Questions

Blockchain and Bitcoin 101
#81

1 UTXO é o saldo positivo restante de uma carteira, proveniente de uma transação anterior.

2 Caso a soma de todos UTXOs seja menor que o valor da transação, a transação não seria aprovada. A transação somente será aprovado caso a soma de UTXOs da carteira seja maior que o valor da transação e caso exista diferença entre o valor da transação e o(s) UTXO(s) haverá uma transação de retorno, que corresponderia ao troco - taxa.

3 A carteira leva em conta as taxas pagas mais recentemente e calcula qual seria a taxa baseada nisso e na urgência estipulada pelas configurações da carteira. Outra forma seria permitir ao usuário escolher a taxa.

4 Utilizando novos endereços a cada transação. Utilizando Torbrowser para realizar operações, para evitar que serviços de rastreamento associem seu IP a suas chaves públicas. Utilizando serviços de mixer para embaralhar as transações. Tomar cuidado ao receber transações de fontes em que a fonte da transação esteja identificada por KYC.
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#82
  1. Transactions sent to my wallet that now can be spent.
  2. The transaction wont go through
  3. It will calculate the transaction fee based on the difference betwen the available UTXO and the amount requested to be sent.
  4. I can send transactions to another wallet I own to increase security.,
    .
#83
  1. UTXO are unspent transactions
  2. it would reject the transaction, or use other UTXO to make up thee amount if available.
  3. The difference between input and outputs is what it cost you, the wallet would specify the fee.
  4. Using multiple outputs would lend a degree of privacy as no one knows whose address is who’s.
#84

  1. UTXOs are basically the output amount of a transaction that remains unspent, and, therefore, can be spent by the recipient. If Bob sends 1 BTC to Kath, the UTXO is 1 BTC, which is the amount Kath now can spent for an input in another transaction.

  2. If you don’t have enough UTXO, the transaction will simply be rejected.

  3. It takes a look at the previous transaction fees and suggests a transaction fee based upon that, that’d put your transaction into the blockchain reasonably fast. You can set a transaction fee yourself, but setting it too low will simply make your transaction go into the blockchain slower, since miners take the transactions with the biggest fees first. The rule of supply/demand for the service of the miners.

  4. A transaction can have multiple inputs and outputs. If your balance is 1 BTC, and you want to send .5 BTC to Bob, you’ll basically create a transaction sending 1 BTC (because you have to spend everything you got every time you make a transaction), .5 BTC to Bob and .5 BTC to yourself.

To increase your privacy, you could avoid sending the change (.5 BTC) back to the same address it came from, and send it to a new (or more) address(es), owned by you. This way, it’d look like you sent 1 BTC, split up, to e.g. 4 different people, but in fact you sent .5 BTC to the recipient, and the rest (.5 BTC) is divided and sent to your 3 other BTC wallets.

#85

1.UTXOs are the inputs that are sent to an address. Once they are added up that is the balance of the wallet.
2.As long as the sum of all UTXOs can cover the transaction it will be accepted. If the address does not have enough UTXOs then the transaction will be declined
3.Based on previous transactions.
4. You can send yourself your own bitcoin back to a different address making it very hard to know who has the bitcoin.

#86

  1. Unspent Transaction Outputs (UTXO) are the change that you can send back to yourself during a transaction. The sum of all your UTXOs is the maximum amount you can spend in a future transaction.

  2. If I don’t have any single UTXO that is large enough to cover for my transaction, I will use several UTXOs together as input. If I don’t have enough UTXOs then the transaction cannot be created.

  3. A bitcoin wallet doesn’t specify the transaction fee when creating a transaction, because it is calculated by substracting the output(s) from the input(s).

  4. I can use the notion of transaction inputs and outputs to increase privacy in my transaction, by using a lot of different addresses controlled by myself, as outputs.

#87
  1. Describe what Unspent Transaction Outputs (UTXO) are.

UTXOs are transactions that a user received but has not spent yet.

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

You will get a transaction back to your account for the same amount of your total UTXOs.

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

The wallet would deduct the total amount of your transactions from your UTXOs.

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

Each transaction has its own unique ID. There is no single account id that holds the details of all transactions.

#88
  1. UTXO is the difference between the sum of input transactions and the sum of output transactions.
  2. The transaction maybe never collected from a miner to make it part of the blockchain.
  3. The wallet checks the recently transactions fees.
  4. You could send your bitcoin to some new addresses which are controlled from your private key.
#89

1.) an (single) UTXO is a part of your balance, which is in the blockchain and “belongs” to your private key. A wallet figure out all your UTXOs (belonging to your private key - at this point, I don’t know how this is done by a wallet, means technically - deeper implementation of searching and matching private key and public keys) and builds your total balance.
2.) more than one UTXO is used to build a TX which covers the sum of the transaction (including fees)
3.) The transaction fee is basicly calulated by the difference of outputs-inputs(UTXOs)
4.) If a TX sent to multiple (public) addresses, which can be also your addresses, it’s hard to find out, which belongs to your wallet (especially if they didn’t have further outputs, I think) or “real” receipients

#90
  1. UTXOs are Unspent Transaction Outputs. They are stored in your Wallet. Basicly, this is the balance in your wallet.

2.Transaction = UTOXs plus fees If you didn’t have any single UTOX that is large enough to cover your transaction, the wallet would check to see if there are any more UTXOs that will total up and cover the transaction - If the total number of UTXOs in the wallet will cover the transaction plus the fee the Wallet willconstruct the transaction for you, calculate the fee for you , and give you the fee that gets you into the blockchain the fastest and sign the transaction - if the total UTOXs in the wallet don’t cover the transaction plus the fee the Wallet will not execute.

  1. the Wallet check the blockchain and calculates the fee - sometimes it will use a higher fee to get you into the blockchain quicker.

  2. By using several addresses and outputs which can result from one transaction.

#91

1- Transactions that are coming into your BTC address that you have not spent yet
2- Transaction will not go through
3- Sats per byte in a block
4- Use different address while sending/ receiving bitcoins

#92

  1. UTXO’s are transaction which you received but are not yet spent any further. They represent your wallet balance

  2. Multiple UTXO’s are combined till at least the demanded value plus fees is reached. If the combined UTXO’s exceed the demanded value an additional transaction is added returning the excess back to your wallet.

  3. The bitcoin wallet recommends a reasonable fee for the transaction. The fee it self is deduced from the sum of transaction input minus the UTXO’s output.

  4. Use multiple inputs and outputs. The more are combined and the more outputs you send to the harder is to track which of the addresses is your own. Furthermore to increase privacy it may be recommended to use a different address for every transaction to be received.

#93
  1. UTXOs are inputs from other people that I received.
  2. My wallet would sum up other UTXOs until it was large enough to cover, and then send the difference back.
  3. Input minus the output
  4. You could send your outputs to multiple wallets that you controlled since no one would know those wallets are yours
#94

1. Describe what Unspent Transaction Outputs (UTXO) are.
UTXO`s are the total of the transactions that you have received, but not spent.
2. What would happen if you don’t have any single UTXO that is large enough to cover for your transaction?
The transaction would be rejected.
3. How would a bitcoin wallet specify the transaction fee when creating a transaction?
It would calculate how fast some of the previous transactions were excepted on the block chain and use an average of those fees. The input minus the output would be the transaction fee.
4. How could you use the notion of transaction inputs and outputs to increase privacy in your transaction?
By sending 3 or 4 transactions, with different addresses.

#95
  1. They are the output of previous transactions that were received and they can now be spent by the recipient.
  2. Your wallet will look for all other UTXO to determine if you have enough to spend. If you do then you can complete the transaction and return the balance to yourself as an UTXO. If not enough the transaction will be rejected.
  3. The wallet would look at previous recent transaction fees and suggest a fee that would get your transaction into the blockchain fairly quickly. You can still decide to set the fee yourself but if it is lower then you will have to accept that the miners will not prioritize your transaction as highly for the next block. tx fee = inputs - outputs.
  4. By using a new wallet address for each transaction, and especially for returning yourself change, you can remove the association that you may have had with a specific wallet address. You can also breakup the change amount into multiple addresses so it looks like there is no change at all and all outputs were being spent.
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#96

Unspent transaction outputs (UTXO) are summed by the wallet to show your bitcoin balance. Each UTXO can be used as an input for a future transaction. It’s a little confusing when we’re used to thinking in terms of ledgers where we don’t specify the inputs for a transaction - we just take from the balance to know how much we can spend. With the UTXO model each transaction is connected to prior transactions on the blockchain. One output where you received “coins” can be used as an input for the next transaction.

The wallet would determine which UTXOs could be summed to cover the transaction. Change left over from the transaction is returned to the wallet. Else, if there’s not enough UTXO the wallet couldn’t make the transaction and the blockchain would never see it.

Wallets determine a fee for the transaction based on the size of the transaction which deals with the amount of inputs or UTXOs used to create a number of outputs. Certain wallets allow one to prioritize their transaction by selecting a higher fee, and vice versa. Miners will select transactions with the highest fees to process first. The sum of inputs minus the outputs equals the transaction fee.

Anyone can look at a blockchain explorer to see the inputs and outputs and fees for any transaction. Since your wallet determines the inputs and fees for a new transaction, you can vary the outputs to increase your privacy. By using several output addresses in a transaction it makes it more difficult to trace, but not impossible. The key to enhanced privacy would be to not spend from an address that is publicly posted or known to have come from an exchange which is associated with your identity. Use a different wallet address for each transaction and for receiving change from spending your bitcoin

#97
  1. Describe what Unspent Transaction Outputs (UTXO) are.

UTXO’s are unspent outputs from a previous transaction.

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

You wouldn’t be able to complete the transaction unless you added another UTXO to the transaction so you had the value you needed.

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

The wallet would specify the fee, total inputs minus the total outputs.

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

While making transactions you could increase the outputs and inputs the more you increase it the more privacy you add to your transactions.

#98
  1. Describe what Unspent Transaction Outputs (UTXO) are.
    It’s the funds that a wallet received that aren’t spent yet.
  2. What would happen if you don’t have any single UTXO that is large enough to cover for your transaction?
    You could use several UTXO to cover your transaction.
  3. How would a bitcoin wallet specify the transaction fee when creating a transaction?
    It would estimate a fee that is high enough that the transaction gets into a block in a reasonable time. To do so, it can refer to fees paid in former blocks.
  4. How could you use the notion of transaction inputs and outputs to increase privacy in your transaction?
    You could increase the number of outputs that go to your own wallet to make tracking of the funds flow harder.
#99
  1. UTXOs are outcomes of transactions from the past to a particular wallet adres in the blockchain ledger, not yet spent.
  2. The wallet takes more UTXOs and makes a (UTXO-fees) to the same input adres. (UTXO-fees) is the transaction balance of total input minus actual spending.
  3. The wallet would look what the actual fees are for a reasonable time to get the transaction in the blockchain and makes a proposition.
  4. Use different wallet adres(ses) for your transaction balance .
#100

1-Unspent Transaction Outputs or UTXO’s are transactions made from someone else to you so you can have a balance to make spends in the future.

2- The wallet will calculate the sum to be spend with your others UTXO’s by checking the blockchain to have the right amount ready to be send and make the transaction.

3- A wallet communicates with the blockchain and check for the latest fees to give you the exact fee for the transaction you’re about to make by calculating the input - output. Some wallets let’s you pick how much fee you would like to be charge for a transaction.

4- By spending the amount to the other person and sending the rest of the balance back to you but using another wallet address.