Bitcoin qt account login

However, Alice will neither be allowed to take back the unspent output she transferred, nor will she be able to spend it again. Alice has a problem: To resolve this dilemma, Alice uses a transaction that splits her payment, a feature fully supported by Bitcoin.

In the previous examples, Alice directed change into the same address she spent from. Privacy depends on the strict separation between addresses and personal identities, a model referred to as pseudonymity. Any observer capable of linking Bitcoin addresses to personal identities can begin to draw conclusions about money transfers between people. Users make this job more difficult by sending change to newly-created addresses.

To see why, imagine a transaction that sends funds from Address A to Address B. If change is returned to Address A, the block chain clearly reveals that the person controlling Address A paid the person controlling Address B. The same reasoning holds if two or more addresses are involved.

Any transaction involving Address A as a sender reveals the receiving address unambiguously. Should the identity of the person controlling either receiving or payment addresses become known, the identities of the other parties could become known as well.

Now imagine that Address A initiates a payment to B, but this time directs change to a newly-generated change address C. The identity of the person controlling Addresses B or C may or may not be the same as the identity of the person controlling Address A.

Given another transaction from Address C, the picture becomes even murkier. Which of the transfers represent payments and which represent the receipt of change? An observer trying to link personal identities to addresses must gather more secondary information and expend more resources when all parties send change to newly-created addresses. Coordinating multiple addresses is a complicated task.

Wallet software frees the user from the need to do this manually. Although change addresses play a key role in improving privacy, wallet developers can implement this feature in a number of ways. Four strategies are currently in use, each with its own implications for privacy and security. Incorrect use of Bitcoin change addresses account for many cases of loss or theft of funds.

Here are some disaster scenarios and ways to avoid them. Understanding the importance of backups, she created an encrypted wallet backup long ago and stored it in a safe place. Alice bought a new hard drive and then re-installed Bitcoin-Qt on it. She then restored her wallet backup. To her horror, Alice discovered the restored wallet was empty. Alice generated enough change addresses to overflow the original pool of Restoring the backup only restored empty addresses.

Using data recovery tools, Alice may be able to salvage the Bitcoin-Qt wallet from the faulty hard drive, and with it her lost funds. Bob uses Electrum to send infrequent bitcoin payments. Worried about possible theft, he wanted a way to keep an eye on his bitcoin balance from one of his many devices. Bob decided on blockchain. A few weeks later, Bob made a 0. After receiving his merchandise, Bob decided to check his balance with blockchain.

Disturbingly, Bob discovered that part of his Overstock payment was transferred to an unknown address. Thinking that his computer running Electrum had been compromised, Bob re-formated the hard drive. This cleared the balance from the sending address, the only one Bob was monitoring. Electrum encourages the storage of its word address generation seed in a safe location. Should Bob still have access to the seed, he can re-generate his old wallet and recover the change from the Overstock transaction.

Carlos is a saver. One day Carlos noticed a deal on new laptops at Overstock and decided to pay using one of his saved bitcoins. But Carlos had a problem: After paying Overstock, he exited the program.

Carlos was worried about leaving any trace of his private key on his computer, so he securely deleted MultiBit and its data directory. He then returned his paper wallet to its safe location. To his shock, the balance read zero. Nineteen bitcoins were sent to an unfamiliar address on the same day as the Overstock payment.

The 19 missing bitcoins were sent to a change address, leaving his paper wallet empty. In securely deleting the MultiBit data directory, Carlos lost any chance of recovering the missing funds.

Dave runs Bitcoin-Qt on two computers, a laptop and a desktop in his garage. Wanting to use both computers to make payments, Dave copied a clean wallet. After making many payments without a problem from both computers, Dave noticed something odd one day. These transactions are called nLockTime transactions because they can only be spent and confirmed by the network after a specific period of time. If the service becomes unavailable, you simply wait until the specified period 90 days by default , then sign and send the transaction using our open source recovery tool garecovery.

Once the nLockTime period expires these nLockTime transactions would allow you to recover the funds in the 2of2 account without requiring GreenAddress's signature. This also means that any limits placed on your spending in GreenAddress, such as 2FA requirements, cease to be enforceable by GreenAddress, and that these funds are no longer available for use in instant transactions because GreenAddress cannot guarantee that you have not tried to double spend them. At this point GreenAddress will prompt you to redeposit the coins by sending them to yourself.

This creates a new nLocktime transaction for you, while re-protecting the coins by once again requiring a GreenAddress signature to spend them. In this way you can take advantage of instant transactions from 2of2 accounts, while always being sure you can retrieve your funds if the service is off-line. The redeposit operation is a standard bitcoin transaction and as such is subject to the usual network transaction fees.

You can place your funds in a GreenAddress 2of3 account, in which case GreenAddress does not generate nLockTime transactions and therefore no redeposits are necessary.

You can increase the nLockTime period on your account which will reduce the frequency of the redeposits. The downside of this is that should you need to recover your funds for example, because you lose your two factor authentication you will have to wait for longer. We recommend that you redeposit your funds when reminded, however redepositing is optional and failure to redeposit will not necessarily lead to the loss of any funds. The main consequences of not redepositing are:.

The funds in the account will no longer be eligible for instant confirmations because GreenAddress can no longer guarantee that you have not tried to double spend them. It becomes possible that anyone with access to both your mnemonic and the nLockTime. No, GreenAddress does not support this. GreenAddress will only sign standard bitcoin transactions. Yes, our https site supports Tor users. Our mainnet production site is at http: Unfortunately, many banks and payment services such as PayPal don't yet support Bitcoin directly.

For the time being, you can exchange your money using bank transfers and sometimes debit or credit cards via an intermediary like a Bitcoin exchange or a broker. There are also online services and communities where you can arrange to exchange cash for Bitcoin. This is an area of rapid change and innovation and so we do not list or specifically recommend any services in this space.

The best service for you depends on many factors. We suggest you locate local services using your favorite search engine and carefully review any potential options. You should see new transactions in your wallet within seconds of it being sent by the payer. If you can not see your transaction in a block explorer, it probably means it is still propagating or failed to do so for example, setting the fee too low can cause transactions to be dropped.

We have sensible rate limits to prevent the service from denial of service attacks. It is extremely unlikely that a user will encounter these limits under normal use.

If you find that you are hitting a rate limit, please contact support with the details. If you have a requirement that exceeds the current limits, please feel free to contact us to discuss your needs further. Addresses change constantly for privacy and security reasons. Re-using old addresses makes it easier for others to group transactions together and can be less secure. While GreenAddress does correctly process multiple payments to the same address, we recommend not re-using them.

Addresses should be thought of as one-time receipt IDs rather than as unchanging identifiers such as traditional bank wire details. Please see the API documentation for more details. All previously generated addresses are available in the Receive tab under Advanced Options when using the Chrome or Cordova wallet clients. Your private keys are not stored. They are derived on demand from your mnemonics as a seed to a BIP32 hierarchical wallet.

Your mnemonics and private keys are never sent to the server. The server receives the public key and chaincode for generated addresses only. When you create a PIN, a random bit AES password is created and used to encrypt your mnemonics and store them on your device in encrypted form.

This password is sent to the server and destroyed on the client. If the server is given the correct PIN when logging in, it will return the password to the device in order to decrypt the mnemonics. If the server is given the wrong PIN three times, it will destroy the password at which point the user must use their mnemonics to log in.

Note that the server never sees your mnemonics at any point. If you can't remember the PIN you use to login to your wallet, you will need to use your mnemonics to log in instead. After entering the wrong PIN three times, the back end service will delete its copy of your wallet's random decryption key, at which point the PIN can no longer be used.

Your wallet client will then ask you to login using your mnemonics and you can resume using the service as normal. The service never knows your mnemonics or passphrase; We cannot help you recover them if they are lost. If you have a wallet with PIN entry enabled, you can use your PIN to log in to the wallet and then view the mnemonics from the settings menu.

You should then write them down and store them safely. In all other cases you will only be able to retrieve your mnemonics by brute force trying various combinations of valid words. This is similar to how a hacker might try to break into your wallet, and is not generally feasible. You should research third party services for wallet recovery, as GreenAddress does not offer assistance or support for wallet cracking for obvious reasons. You should always have at least two different two-factor options enabled.

As long as you keep these backups you can maintain access to your coins even if you lose access to one method for any reason. In cases where you have lost access to all of your two-factor methods, we have no way to return control of your coins to you.

We take our users' security very seriously; we have never disabled two-factor authentication for any user once enabled, unless explicitly authorized to do so via another two-factor authentication method. We follow the restrictions that you placed on your account without exception. If your coins are in a 2of2 account then you will need to recover your authentication - we cannot disable it in this or any other case.

Click on Confirm Transfer to complete the transaction. If you have previously sent bitcoins to this address, no confirmation is needed the transfer will be sent immediately. Related articles Wirex App: How to send funds to external bitcoin wallet What is the blockchain fee? How and why to verify Wirex account? Wirex virtual card limits Wirex fees. Was this article helpful?