_ Here's how it works: Anybody can ask a question Anybody can answer The best answers are voted up and rise to the top up vote down vote favorite 2 Let's say I have 10 bitcoins.I won't be using 8 of them any time soon.How can I put the 8 in a separate "offline" wallet not related to the bitcoin client?This would be a good security measure.If the bitcoin client is ever compromised, only the remaining 2 bitcoins would be at risk.It seems rather reckless to have all of one's savings in the same wallet.wallet up vote 6 down vote Go to your Bitcoin data directory Backup your wallet.dat to a safe location Move your wallet.dat away from the data directory Start Bitcoin.It will create new wallet.dat Get an address from the new wallet, save it in notepad Encrypt the wallet with some passphrase you will remember for a long time Turn Bitcoin off Go back to your Bitcoin data directory Take the new wallet.dat and store it somewhere safe Move your old wallet.dat file back into the data directory Run Bitcoin again.

Send 8 Bitcoins to the address you saved in notepad Now you have two wallet files - one with 2 bitcoins for your normal use, one with 8 bitcoins for keeping them safe.Just make sure not to lose either of the two wallets, or you'll lose your coins.Keep your wallet.dats backed up and don't run duplicates at the same time.bitcoin 1000 satoshiup vote 1 down vote /creating-an-offline-bitcoin-wallet/ Steps for creating an offline bitcoin wallet Open the folder that contains your wallet.dat file For Windows users: Go to Start -> Run (or press WinKey+R) and run this: %APPDATA%\Bitcoin For Linux users: By default you Bitcoin should be here: ~/.bitcoin/ For Mac users: By default you Bitcoin should be here: ~/Library/Application Support/Bitcoin/ Back up your wallet.dat file to a secure location Move your origional wallet.dat file out of this directory Start the Bitcoin client The Bitcoin client will automatically create a new wallet.dat file and a new address Copy the address and save it in notepad Encrypt the wallet with a secure passphrase Close the Bitcoin client Go back to the Bitcoin folder Move the new wallet.dat file out of this folder and store it somewhere safe.bitcoin farm malaysia

I suggest making multiple backups of this on multiple media types.CD, SD Card or a portable hard drive Move your old wallet.dat file back into the Bitcoin directory Run the Bitcoin client You can now send bitcoins to the address you copied down and they will be securely stored offline To get the offline wallet back online.bitcoin kurs 2009Move out the existing wallet.dat file and replace it with you offline file.kurs bitcoin 2009Open the Bitcoin client and you will now have access to the bitcoins associated with that wallet.bitcoin on linux mintup vote 1 down vote You better use off-line machine for generation secure bitcoin address.bitcoin exchange mount

(see vanitygen) Thereafter send your money from on-line machine to this address.Bitcoin now are safe.Nobody know your private key.up vote 0 down vote To save the copy/rename of your wallet.dat you could also use one of the alt-clients that have built in multiple wallet support.Both Armory and MultiBit show multiple wallets directly in the user interface.up vote 0 down vote It seems there's a more secure and easier method., print it off or memorize it or keep it on a USB flashdrive.Then he can go to his Bitcoin client, send 8 bitcoins to the public address of that newly-created private key and that will be most secure.Even if his client is hacked or PC crashes, those 8 bitcoins are damn secure.up vote 0 down vote Step 1: <-- Wiggle mouse, hit print.Step 2: client, send money, enter Bitcoin address, Qty 8 BTC.Browse other questions tagged wallet or ask your own question.How to Set Up a Split Bitcoin Wallet in Qubes What is a “Split” Bitcoin Wallet?

A “split” bitcoin wallet is a strategy of protecting your bitcoin by having your wallet split into an offline “cold storage” wallet and an online “watching only” wallet.A “Watching” Wallet and a “Cold” Wallet Create a Debian 8 backports template using the Qubes VM Manager or running qvm-clone debian-8 debian-8-backports in dom0.Add backports to the sources for the new template by opening a terminal in the new template, run sudo vi /etc/apt/sources.list and add deb http://http.debian.net/debian jessie-backports main.(If you are new to vi text editing, type i to be able to edit, and when done editing press ESC then type :x and press ENTER.)Update source list: sudo apt-get update.Install electrum from backports: sudo apt-get -t jessie-backports install electrum.shut down your debian-8-backports template create an offline-bitcoin qube based on debian-8-backports using the Qubes VM Manager or running qvm-create -t debian-8-backports -l black offline-bitcoin and qvm-prefs -s offline-bitcoin netvm none in dom0.

follow the electrum documentation in creating an offline wallet create a watching-bitcoin qubes based on debian-8-backports connecting to the internet how ever you prefer using the Qubes VM Manager or running for example qvm-create -t debian-8-backports -l green watching-bitcoin and qvm-prefs -s watching-bitcoin netvm sys-whonix in dom0.follow the electrum documentation in creating an online watching-only wallet Important Notes The private keys (xpriv) should never be moved outside of offline-bitcoin.For copying out the public keys (xpub), Qubes provides two secure, convenient methods: the inter-VM clipboard and inter-VM file copy tools.Compared to traditional physically air-gapped machines, these tools makes it very easy to copy out public keys.Jump to: , Casascius holding early paper wallets In the most specific sense, a paper wallet is a document containing all of the data necessary to generate any number of Bitcoin private keys, forming a wallet of keys.

However, people often use the term to mean any way of storing bitcoins offline as a physical document.This second definition also includes paper keys and redeemable codes.A paper key is a single key written on paper that is used multiple times like a wallet (this is strongly discouraged).A redeemable code is a single key intended to be funded and "redeemed" only once: these are commonly used for gifts and as part of physical Bitcoin coins/notes.Storing bitcoins on paper wallets is not safe unless very strict security precautions are undertaken during their initial preparation.Contents 1 2 3 4 5 6 7 Generating paper wallets is not recommended from an online PC.Malware malware on the PC may be able to steal your paper wallet keys.Even if you generate paper wallets securely, they are still vulnerable to loss and theft.Unencrypted paper wallets must be kept safe like jewels or cash.For additional security paper wallets can be split into shares, requiring X of Y shares (e.g., 3 out of 5) to reassemble the secret key.

By creating a keypair, one can store bitcoins on a physical medium to be left as a tip or a gift.The recipient then sweeps the private key to their own wallet.A trusted provider can hide the private key inside a tamper-resistant token, and issue them as a form of bitcoins.This requires those who accept it as payment to trust that when the provider produced the tokens, they loaded them with the correct amount of bitcoins, and that they have not been tampered with since then.To redeem the bitcoin value, the token must be destroyed to access the private key.Often a bitcoin address is embedded on the outside visible, but there is no guarantee (without destroying the token) that this matches the private key inside, or, even if it does, that the private key is not replicated on multiple tokens or saved by the producer.Proper paper wallets are often a very secure way of storing bitcoins, since they are not typically exposed to malware.They can also be easily stored securely in safes and safe deposit boxes.

However, it may be more difficult to securely "backup" paper wallets, and due to the current sub-optimal software support, it may be easier to make a mistake that causes loss of bitcoins.Sometimes people try to use single keys as true bitcoin wallets.However address reuse is very bad for privacy and security.Because of this, one is forced to choose between hazardous options: Therefore, it is highly recommended that you use proper paper wallets which allow you to generate an infinite number of addresses from a single seed.Paper keypair with private key secured beneath folds Proper, multi-key paper wallets usually take the form of a multi-word HD wallet seed mnemonic.The list of several words corresponds to some binary data that is used to generate all of the addresses.Words are used to make it easier to avoid and correct errors.Trying to memorize an entire seed mnemonic is very difficult and is generally not recommended.A single key (for use in insecure single-key paper wallets or redeemable codes) can be represented in several formats, but typically the Wallet Import Format (WIF) is used, since keys represented that way are very short (51 characters) and thus easy to re-enter when importing or "sweeping" it for withdrawal.

The private seed is used to prove your right to spend the bitcoins transferred to the paper wallet, and as such should be kept hidden and secret.If the private seed on a paper wallet is exposed (for example in a photograph) then the wallet may be used by anyone who sees it.To guard against accidental revelation, the private key displayed on the paper wallet may be encrypted or split into several different parts (for example using Shamir's secret sharing scheme).At the very least, the private key should be well hidden e.g.by folding the wallet in half and sealing it shut.Currently, at least Armory and Electrum support generating mnemonic codes for their wallets, which can be written down or printed to make a multi-key paper wallet.Several tools exist for producing single keys, including Bitcoin Address Utility, vanitygen, and Cwallet.Again, using single keys for anything except one-time transfers of bitcoins is strongly discouraged.Some websites feature free open-source client-side keypair/wallet generators written in JavaScript.

Keypairs/wallets generated by JavaScript or using websites are inherently weak and insecure, and unless the code of the website is audited every time it is used, it may leak the generated keys back to the server—especially if un-audited Javascript is downloaded and run locally.Even with careful code auditing, browser plugins or other websites may compromise the environment.Some advanced printers have internal storage (even hard drives) that preserve copies of printouts.This is a risk if someone gets access to your printer, or if you dispose of your printer.There is also the possibility that a smart enough printer can be hacked.(Consider StuxNet which was able to rewrite the firmware of non-computer devices indirectly connected to the Internet) If this concerns you, use a "dumb" printer, and never let your printer have access to the Internet or to an Internet-connected computer.An alternative using a printer for paper wallets is to write the private key and address with your own hand.Base58Check encoding used for Bitcoin addresses and private keys specifically excludes characters that look similar like 0OIl.

The mnemonic recovery seeds used by wallets like Armory and Electrum are also suitable to be written by hand.This section applies only to single-key paper "wallets".Paper keys, when used as wallets, are very different from wallets such as Bitcoin Core in that there is only one address in a paper key rather than a hundred or more online keys that are managed with full software assistance from Bitcoin Core.There are various methods for copying the private key data to other wallets.Note that importing a private key that may be compromised can result in the entire wallet becoming insecure.For this reason, sweeping (or sending the entire amount to a fresh address) is generally recommended over plain importing.Because paper wallets only record the private key and address, wallet software which redeems the bitcoins must somehow learn about the balance of the wallet before being able to spend it.The solution with the best privacy properties is to import the private key into bitcoin-qt and rescanning.