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12

With the Bitcoin Core client, you can create a transaction sending coins to several addresses. On the "Send" tab, there is an "Add Recipient" button at the bottom of the screen; click it as many times as needed to add a form for each recipient. Enter all the addresses and the corresponding amounts to be sent, and you will get a single transaction sending ...


11

TL;DR: Just read the second paragraph of "Concrete Numbers". Wallet Recommendation: Electrum Doing this in Electrum is very simple. Just switch to the Send tab and then (in the menu) choose Tools → Pay to many. The "Pay to" field will become a text area and a popup will open, telling you how to send money to many addresses. Note that the unit of the ...


10

I don't use MultiBit, but just checked its source code to see what the message you quoted means. It turns out that the message is shown when the amount you're asking to send plus fees is less than the "available balance", which is defined as: Balance that can be safely used to create new spends. This is all confirmed unspent outputs minus the ones spent ...


9

In this scenario, neither address A nor address B had a sufficient balance to pay 0.5 BTC by itself. The two together did have enough. So, the clients are intelligent enough combine the amounts of two addresses together in order to meet the desired transaction amount. Unfortunately, the combination has the effect of sending bitcoins to yourself as "change" ...


9

As long as you're running a relatively recent version of Bitcoin Core you can use Coin Control. This feature let's you pick which unspent outputs will be used in the transaction. To enable Coin Control, go to Settings->Options->Wallet->'Enable coin control features'. Now in the Send window, you can click 'Inputs...' to select which unspent outputs you want ...


7

If the address is valid, the transaction will succeed. If nobody knows the private key for that address, the money is lost forever. For all practical purposes, it's impossible to guess the key for an address that you made up.


7

Transactions have a list of inputs and a list of outputs. Many transactions just have two outputs, one that pays to the receiver of the funds, and one that sends the leftovers ("change") back to the sender of the funds. Since this is the most common transaction type, this is what most bitcoin interfaces are designed for. With that said, there are a few ...


6

Yes, all of those are stored in the wallet.dat file. I myself have successfully migrated the wallet file to a new computer and have the addresses and descriptions intact.


5

The coin selection that the client does is performed behind the scenes, the client takes care of the details. But if you are curious to know what happens behind the scenes: INPUT: Address: A 1.0 BTC Address: B 1.0 BTC OUTPUT: Address: C 2.0 BTC FEE (derived as inputs - outputs): 0.0 BTC This is assuming you didn't pay a fee. Let's say instead you ...


5

From the bitcoin wiki: Several of the characters inside a Bitcoin address are used as a checksum so that typographical errors can be automatically found and rejected. The checksum also allows Bitcoin software to confirm that a 33-character (or shorter) address is in fact valid and isn't simply an address with a missing character. In other words, ...


4

Under Receive Money, Archived, find the address in question ("username (Sent Via XX"). Click this button to bring it back to active addresses: Under Send Money, Custom, send all the money from that address to another address in your wallet. You can now archive the address again.


4

Say your 1 BTC balance was the output of a single transaction. To pay someone .5 BTC, you have to claim the output of that transaction. Then you have to pay the .0005 BTC fee. That leaves .4995 BTC which need to be left as an unclaimed transaction output for you to spend later. To perform another transaction, you need to claim that .4995 BTC output from ...


4

The problem itself is not Bitcoin-specific per se. It's a matter of being able to verify the sender of some data. Bitcoin addresses are only designed to be immune to typos (they contain a checksum), but otherwise the protocol does nothing. One can, however, do a couple things to make sure a proper address is sent and received: One can use a vanity address ...


4

I'd suggest you read this blog post about using the raw Bitcoin protocol: http://www.righto.com/2014/02/bitcoins-hard-way-using-raw-bitcoin.html To answer your question, you should specifically read the "How to find peers" section of that post. Specifically this part: There's a chicken-and-egg problem, though, of how to find the first peer. Bitcoin ...


4

If you call bitcoin-cli settxfee <fee> just before call bitcoin-cli sendtoaddress "1LipeR1AjHL6gwE7WQECW4a2H4tuqm768N" <value> Then the fee will be <fee>. Important note: make sure in the graphic mode (when you start with bitcoin-qt command) the "custom" is selected, otherwise your command settxfee will be ignored (see image bellow). ...


4

Bitcoin transactions are not reversable. The only way for you to get your bitcoins returned is by convincing your business partner to send them back to you.


4

When sending Bitcoin from Coinbase.com to an email address, you are sending the Bitcoin to another Coinbase.com account linked to that email address. So for example, if you had a friend who has a Coinbase.com account and you wanted to send them Bitcoin, you could ask them for their Coinbase.com email address and then send the Bitcoin to that email address, ...


4

You are sending to a bech32 address. The current release of Bitcoin Core does not support bech32 addresses. The address box highlighted in read indicates that the address is invalid to the wallet. The next release of Bitcoin Core will support sending to bech32 addresse as well as full Segwit wallet support.


3

Bitcoin doesn't currently provide any protection against that. Alice and Bob will need to make sure that their communication channel is secure.


3

A Bitcoin transaction can have multiple inputs (and multiple outputs). In the scenario you described, a single transaction will be created, which will include as inputs both the payment to A and the payment to B. Usually, the receiving party will not care what are the inputs of a transaction, he will care that the output will include the expected payment to ...


3

Bitcoin doesn't really have sender addresses. Every transaction consumes some of your coins, and creates one or more new coins, potentially assigned to a different address. What the receiver can see is the transaction, and he can trace which coins it spent, and which addresses those coins were previously assigned to. Some programs/sites use the first such ...


3

This is technically possible and can be easily implemented, but I see two problems, which may be stopping people from creating such a service: Trust: how can the service ensure its clients that it will not steal their money? Security: email is not secure, a man in the middle can access the email message on its way before the recipient, and steal the money. ...


3

The wallet belongs to someone and you've just sent him money. (Can one contact this person and ask for it to be returned?) The key phrase is "can one contact" not "can you force him to give it back." Not unless the owner of that address has publicly stated that she owns that address (perhaps on her blog or on a forum? Try googling). The wallet (as ...


3

Most transactions create an Unspent Transaction Output (UTXO) which can only be spent by the owner of the corresponding recipient address. Any "well-formed address" can receive such a transaction, whether it has been used before or not. Should somebody own the address, they might try to send the money back to the original sending address, however, it is ...


3

The correct configuration parameter is: paytxfee=<amount>, where <amount>is the amount (fee) per kB to add to your outgoing txs


3

Many wallets have the "Coin Control" panel where you can specifically choose which outputs to use in the transaction. Which wallet are you using?


3

You appear to have caught some malware that replaces Bitcoin your addresses with their own when copy-pasting one. You'll probably want to look into removing the malware from your computer. Meanwhile, it is unlikely that you'll be able to recover your bitcoins. The Bitcoin network doesn't have a way of reverting payments. Basically, you're in a similar ...


3

Great question, I've always wondered this too. But im pretty sure that Electrum, by default, will send your oldest unspent outputs first. (Sorry if example is a little repetitive) E.g. If you recieved 0.4 on address A 3 days ago, 0.2 on address B 2 days ago and 0.1 in address A again 1 day ago, it would send 0.4 from address A, then 0.2 from address B, then ...


3

Electrum appears to have two Coin Selection policies that users can select from. CoinChooserOldestFirst selects oldest first prunes any unneeded inputs starting from the smallest standard policy CoinChooserPrivacy randomly selects UTXO until sufficient prunes any unneeded inputs starting from the smallest attempts to create a change within 0.75 and 1.33 ...


3

Unfortunately, there's no distinction between "external" and "internal" transfers in bitcoin. If you want coins to be in another address, you have to pay the transaction fee. That said, you can create a single transaction that does everything you want and only pay the fee once (though, obviously, that transaction will be relatively big, you should still save ...


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