To request bitcoin from someone else you need to provide them with a "Bitcoin address".They look like this 1AhN6rPdrMuKBGFDKR1k9A8SCLYaNgXhty and you might want think of them as a unique address for a payment.Anyone that you give this address to will be able to send you bitcoin from that moment on.Remember that they may keep this address for a long time so you should never abandon a wallet by throwing away the wallet words.It's very unlikely you'll ever have to type a Bitcoin address by hand so don't worry about having to memorise them.Bitcoin addresses are intended to be used just once since for technical reasons (see later) they become a little less secure after you have spent the bitcoin received by them.For this reason MultiBit HD always gives you a new address each time you click the "Request" button.QR codes are a convenient way to transfer information from one machine to another.MultiBit HD will generate one for you by clicking the QR code icon near the Recipient box.This makes it easy for you to request payment from smartphones with Bitcoin wallets installed.Once you have requested a payment it appears in the Payments screen with the status 'You requested'.

At this point you are waiting to get paid, the general process is as follows:The other person sends you bitcoin and the status moves to "Unconfirmed" to indicate that the Bitcoin network is processing it.You will also get a green alert bar with a message indicating that bitcoin is incoming.You will see at the top of MultiBit HD the message "+ Unconfirmed: mBTC xyz", where "xyz" is the amount of bitcoin they sent you.You cannot spend unconfirmed transactions in MultiBit HD since they could fail to confirm for many reasons.When your request has been paid and before it is confirmed the status of the transaction moves to "Receiving".If the other person only sends you part of the bitcoin you requested, the status is "Part paid" until they send you all that you requested.Bitcoin miners process all the unconfirmed transactions and put them into blocks.Once this happens your transaction is confirmed and you can spend it.This normally takes between 10 minutes and an hour.Once your transaction is confirmed in a block its status changes to "Received".You can view many details of a particular transaction as follows:Use the Payments screen.

select the payment request and click the Delete button.You can undo this if you select the wrong one.This requires a technical explanation of how Bitcoin addresses are created.In short, a Bitcoin address is a hash of a hash of an elliptic curve public key (RIPEMD160(SHA256(pubkey)) and some other integrity checking information.bitcoin dovizThis process makes the address short so it doesn't take up much space in the block chain, and also makes it very hard to work back from the address through two different hashing algorithms to arrive at the original public key.During the Bitcoin spending process the public key is exposed in the block chain for all to see.bitcoin fastest gpuThis is necessary to allow everyone to verify that the address matches the public key and that the private key was used to sign the transaction, but removes the hash of a hash protection.ecb bitcoin report

This weakens the security from that of an address to simply the mathematical relationship between a public and private key within elliptic curve cryptography.While this is immensely strong, it is still weaker than the additional hash of a hash which is why addresses should not be re-used.Last updated: 20th March 2015 Bitcoin transactions are sent from and to electronic bitcoin wallets, and are digitally signed for security.Everyone on the network knows about a transaction, and the history of a transaction can be traced back to the point where the bitcoins were produced.Holding onto bitcoins is great if you’re a speculator waiting for the price to go up, but the whole point of this currency is to spend it, right?So, when spending bitcoins, how do transactions work?Here’s the funny thing about bitcoins: they don’t exist anywhere, even on a hard drive.We talk about someone having bitcoins, but when you look at a particular bitcoin address, there are no digital bitcoins held in it, in the same way that you might hold pounds or dollars in a bank account.

You cannot point to a physical object, or even a digital file, and say “this is a bitcoin”.Instead, there are only records of transactions between different addresses, with balances that increase and decrease.Every transaction that ever took place is stored in a vast public ledger called the block chain.If you want to work out the balance of any bitcoin address, the information isn’t held at that address; you must reconstruct it by looking at the blockchain.If Alice sends some bitcoins to Bob, that transaction will have three pieces of information: To send bitcoins, you need two things: a bitcoin address and a private key.A bitcoin address is generated randomly, and is simply a sequence of letters and numbers.The private key is another sequence of letters and numbers, but unlike your bitcoin address, this is kept secret.Think of your bitcoin address as a safe deposit box with a glass front.Everyone knows what is in it, but only the private key can unlock it to take things out or put things in.

When Alice wants to send bitcoins to Bob, she uses her private key to sign a message with the input (the source transaction(s) of the coins), amount, and output (Bob’s address).She then sends them from her bitcoin wallet out to the wider bitcoin network.From there, bitcoin miners verify the transaction, putting it into a transaction block and eventually solving it.Because your transaction must be verified by miners, you are sometimes forced to wait until they have finished mining.The bitcoin protocol is set so that each block takes roughly 10 minutes to mine.Some merchants may make you wait until this block has been confirmed, meaning that you may have to make a cup of coffee and come back again in a short while before you can download the digital goods or take advantage of the paid service.On the other hand, some merchants won’t make you wait until the transaction has been confirmed.They effectively take a chance on you, assuming that you won’t try and spend the same bitcoins somewhere else before the transaction confirms.

This often happens for low value transactions, where the risk of fraud isn’t as great.Because bitcoins exist only as records of transactions, you can end up with many different transactions tied to a particular bitcoin address.Perhaps Jane sent Alice two bitcoins, Philip sent her three bitcoins and Eve sent her a single bitcoin, all as separate transactions at separate times.These are not automatically combined in Alice’s wallet to make one file containing six bitcoins.They simply sit there as different transaction records.When Alice wants to send bitcoins to Bob, her wallet will try to use transaction records with different amounts that add up to the number of bitcoins that she wants to send Bob.The chances are that when Alice wants to send bitcoins to Bob, she won’t have exactly the right number of bitcoins from other transactions.Perhaps she only wants to send 1.5 BTC to Bob.None of the transactions that she has in her bitcoin address are for that amount, and none of them add up to that amount when combined.

Alice can’t just split a transaction into smaller amounts.You can only spend the whole output of a transaction, rather than breaking it up into smaller amounts.Instead, she will have to send one of the incoming transactions, and then the rest of the bitcoins will be returned to her as change.Alice sends the two bitcoins that she got from Jane to Bob.Jane is the input, and Bob is the output.But the amount is only 1.5 BTC, because that is all she wants to send.So, her wallet automatically creates two outputs for her transaction: 1.5 BTC to Bob, and 0.5 BTC to a new address, which it created for Alice to hold her change from Bob.Sometimes, but not all the time.Transaction fees are calculated using various factors.Some wallets let you set transaction fees manually.Any portion of a transaction that isn’t picked up by the recipient or returned as change is considered a fee.This then goes to the miner lucky enough to solve the transaction block as an extra reward.Right now, many miners process transactions for no fees.