_ 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 5 down vote favorite I am a new adopter of Bitcoins, forgive the ignorance.(note these are test transactions) I am using the Bitcoin qt client and I am very confused and think I have done something wrong.I have two computers A and B both with Bitcoin qt client on.I have made wallets on both computers.After launching Bitcoin qt client for the first time on computer A I created two addresses using the 'new address' button.I then clicked 'Encrypt Wallet' and entered a passcode.Note I only did this process once, even though I created two addresses.I then transfered two test transactions to the wallet on computer A from Bitstamp.These came through as: /2ziI6.jpg (don't know if anything looks wrong in that picture?)I then tried my first ever test transaction and sent it to the address I created on computer B (I have never encrypted this wallet).

To my surprise this sent, even though I didn't have to enter any kind of passcode on computer A?Plus my address on computer B isn't even encrypted?Does that mean anyone can use the funds I have in my wallet on computer A, without my passcode?The status of the transaction on computer B is also, 8 confirmations?Is this a sign of a mistake.Also the 'from' is marked as unknown - is this important?There is also no lock icon on my QT client, which I have been told there should be if the wallet has been encrypted?I'm confused, please advise.Sorry for my ignorance, I am not a technically minded person but trying to adopt bit coins.bitcoin-core up vote 2 down vote You only need to encrypt each wallet once, no matter how many new addresses you make.It sounds like the wallet encryption didn't happen.Did you maybe not type the same passphrase twice or something?People can only spend your funds if they have a copy of your wallet.So even if you didn't manage to encrypt the wallet on computer A successfully yet, your funds are still safe as long as nobody gains access to your files.

The "8 confirmations" simply means that the transaction is buried 8 blocks deep in the blockchain, and so is very unlikely to ever be reversed.The number of confirmations will go up by 1 every time a new block is added to the blockchain by a miner.The 'from' field is always 'unknown' in my experience.I don't even know what it's for.My lock icon is in the bottom right corner of the client.There are 3 icons, and the lock is the leftmost of them.ethereum gift cardsTry encrypting your wallet again and pay attention to what it says.bitcoin mining average incomeI suspect you didn't type the passphrase the same twice when you tried to encrypt your wallet, so it didn't do it.ethereum defup vote 2 down vote If you encrypt your wallet, it will also be encrypted for all addresses your ever create.bitcoin fiat map

Bitcoin qt will ask you for every transaction you made for the password.At this moment yes, try to encrypt it again, maybe you made a misstake?A confirmation means, that you transaction was successful added to a block and is processed.Some markets or platforms need a certain number of confirmations.Your payment is normal confirmed after 1 confirmation.Yes, there should be a "lock" icon on the right bottom.Try to encrypt your wallet again is it possible.bitcoin isinBrowse other questions tagged bitcoin-core or ask your own question.bitcoin bviJump to: , Contents 1 2 3 4 5 6 7 8 Wallet security can be broken down into two independent goals: In the case that your current wallet hasn't been protected adequately (e.g.iphone bitcoin qrput online with a weaker password): For a brief overview see also: Wallet Security Dos and Don'ts A cold wallet generates and stores private wallet keys offline on a clean air-gapped computer.ethereal band wiki

Unsigned transactions are generated online, transferred offline for verification and signing, and the signed transaction is transferred online to be transmitted to the Bitcoin network.This allows funds to be managed offline in Cold storage.Used correctly a cold wallet is protected against online threats, such as viruses and hackers.Cold wallets are similar to hardware wallets, except that a general purpose computing device is used instead of a special purpose peripheral.bitcoin r7Hardware wallets are special purpose security hardened devices for storing Bitcoins on a peripheral that is trusted to generate wallet keys, verify and sign transactions.A hardware wallet typically holds the private keys in its internal storage and is designed to be malware resistant.The device signs the transactions internally and only transmits the signed transactions to the computer.The separation of the private keys from the vulnerable environment allows the user to spend bitcoins on a compromised computer with reduced risk.

An Internet connected computer that stores your Bitcoins is often referred to as a "hot wallet".Though there are several things that can be done to lower the threat, hot wallets are unavoidably risky.Modern operating systems are highly complexity, leading to a large attack surface.They also constantly leak information without the user’s knowledge or consent.It is very hard to ensure your wallet is secure on an Internet connected computer.For low value wallets, the risk may be acceptable but it is recommended not to keep more in a hot wallet than you can afford to lose.For sums beyond that use one of the more secure methods above (e.g.,.To minimize risk, take care that the system is free of malware, viruses, keyloggers, remote access tools, and other tools that may be used to make remote copies of your wallet, Bitcoin-related passwords, or Bitcoin private keys.When your computer is compromised, the precautions taken below may provide additional protection.Bitcoin transactions send Bitcoins to a specific public key.

A Bitcoin address is an encoded hash of a public key.In order to use received Bitcoins, you need to have the private key matching the public key you received with.This is sort of like a super long password associated with an account (the account is the public key).Your Bitcoin wallet contains all of the private keys necessary for spending your received transactions.If you delete your wallet without a backup, then you no longer have the authorization information necessary to claim your coins, and the coins associated with those keys are lost forever.The wallet contains a pool of queued keys.By default there are 100 keys in the key pool.The size of the pool is configurable using the "-keypool" command line argument.When you need an address for whatever reason (send, “new address”, generation, etc.), the key is not actually generated freshly, but taken from this pool.A brand new address is generated to fill the pool back to 100.So when a backup is first created, it has all of your old keys plus 100 unused keys.

After sending a transaction, it has 99 unused keys.After a total of 100 new-key actions, you will start using keys that are not in your backup.Since the backup does not have the private keys necessary for authorizing spends of these coins, restoring from the old backup will cause you to lose Bitcoins.Creating a new address generates a new pair of public and private keys, which are added to your wallet.Each keypair is mostly random numbers, so they cannot be known prior to generation.If you backup your wallet and then create more than 100 new addresses, the keypair associated with the newest addresses will not be in the old wallet because the new keypairs are only known after creating them.Any coins received at these addresses will be lost if you restore from the backup.The situation is made somewhat more confusing because the receiving addresses shown in the UI are not the only keys in your wallet.Each Bitcoin generation is given a new public key, and, more importantly, each sent transaction also sends some number of Bitcoins back to yourself at a new key.

When sending Bitcoins to anyone, you generate a new keypair for yourself and simultaneously send Bitcoins to your new public key and the actual recipient's public key.This is an anonymity feature – it makes tracking Bitcoin transactions much more difficult.So if you create a backup, and then do more than 100 things that cause a new key to be used, and then restore from the backup, some Bitcoins will be lost.Bitcoin has not deleted any keys (keys are never deleted) – it has created a new key that is not in your old backup and then sent Bitcoins to it.A backup is therefore recommended roughly every 50 transactions (or address creations) just to be safe.No software is perfect, and from time to time there may be security vulnerabilities found in your Bitcoin client as well.Be sure you keep your client updated with the latest bug fixes, especially when a new vulnerability is discovered.We maintain a list a known vulnerabilities on this wiki - you can watch that page to get updates.Note that you don't need to be running the latest major client version: some clients, including the popular Bitcoin-Qt, have older versions available with bugfix-only updates.

If a wallet or an encrypted wallet's password has been compromised, it is wise to create a new wallet and transfer the full balance of bitcoins to addresses contained only in the newly created wallet.Examples of ways a wallet may be compromised are through password re-use, minimal strength passwords, computer hack or virus attack.There are a number of ways to create a new wallet with Bitcoin-Qt or bitcoind but this is a process that has been tested with bitcoind 0.6.3.We use the copy command to minimize the chance of any data loss but you are warned to make backups of any wallet.dat that holds a balance for you.You should now have a new wallet with all the bitcoins from the old wallet.Tomb is a simple tool to manage encrypted storage on GNU/Linux.Among its features are bind-hooks to set up a tomb's contents in the place where other programs expect them, for example in our case mount -o bind the .bitcoin directory in a user's home.//software/tomb) Among the requirements: zsh, cryptsetup, pinentry-curses, gnupg, sudo.

Recommended: wipe, dcfldd, steghide, qrencode.Then create a tomb (we name it bitcoin) with three commands: tomb dig -s 100 bitcoin.tomb tomb lock bitcoin.tomb -k bitcoin.tomb.key This will require you to input again the password you selected.Once open the tomb contents are in /media/bitcoin.tomb Move there your bitcoin wallet: Then create a file "/media/bitcoin.tomb/bind-hooks" and put a single line: Which means that every time the tomb is open, the directory my-safe-wallet needs to be bound to ~/.bitcoin.Just make sure an empty ~/.bitcoin directory exists in your home.Now close the tomb and store its keys safely, make sure you memorize the password.Have a look at Tomb's documentation, there is a number of things you can do like steganography or printing out keys on a paper to hide and such.Every time you like to access your wallet open the tomb and the .bitcoin will be in place.One can also store the bitcoin binary inside the tomb and even start the bitcoin client using the exec-hooks.

Tomb's manual page "man tomb" explains the possibilities.The advantage of this approach over an encrypted home is that it becomes extremely portable across computers and even online shells: a Tomb is just a file and its key can be stored far away, on different shells, usb sticks or mobile phones.The first step is to make a new user.In order for that new user to have an encrypted home directory, you'll first need the encryption utility.Run: Now you're ready to create a new user You'll need to come up with a secure new password for that user.When you get to the prompt 'Enter the new value, or press ENTER for the default', just keep hitting ENTER.Then switch user to the new user.To get to the new user you can use the switch user icon for your system, which on Ubuntu is in the 'System/Quit' screen, or if there is no switch icon on your system you can log out and log back in as the new user.Since the home folder of this user is encrypted, if you're not logged in as that user, data that is saved there can't be browsed, even by a root user.

If something goes wrong with your system, and you need to decrypt the new user's files, you'll need its decryption key.It will ask you for your user's password and give you the decryption key.WRITE DOWN OR SAVE THE CODE IT RETURNS because you will need it if you ever have to pull your data off while the OS is not working.(You can run it again later if you need to, but run it now so that you can get your data if your Linux install gets botched.)The encrypted folder data is not encrypted while it's in memory, and so if it's ever sent to the swap partition it can be stolen from there unless that too is encrypted - be aware that this will mean you cannot use Hibernate anymore, as the bootloader won't be able to restore the hibernation data.Then click on a folder in the new user to display the file browser, then keep going up folders until you see the new user home directory, then right click to bring up the Properties dialog, then click on the Permissions tab, then in the Others section, set the folder access to None.

For secure browsing, open Firefox, and then go into the Edit menu and click Preferences.Starting from the left, click on the General tab, and in the 'Startup/When Firefox starts' pop up menu, choose 'Show a Blank Page'.Then click on the Content tab, and deselect 'Load images automatically' and deselect 'Enable JavaScript'.Then click on the Privacy tab, and in the 'History/Firefox will' pop up menu, choose 'Never remember history'.Then click on the Security tab, and in the Passwords section, deselect 'Remember passwords for sites' and deselect 'Use a master password'.Then click on the Advanced tab, then click on the Update tab, and then in the 'Automatically check for updates to' section, deselect 'Add-ons' and 'Search Engines'.When JavaScript is disabled, the Linux download page will not download automatically, so you'll have to click on the 'direct link' part of the "Problems with the download?Please use this 'direct link' or try another mirror."This solution does not scale; the amount of needed space can grow beyond the image size.

Due to the frequency with which Windows computers are compromised, it is advised to encrypt your wallet or to keep your wallet on an encrypted disk image created by third-party software, such as TrueCrypt (open source) or Jetico BestCrypt (commercial).This also applies to the storage of passwords, private keys and other data that can be used to access any of your Bitcoin balances.Assuming that you have installed the Windows Bitcoin client and run it at least once, the process is described below.To mount the Bitcoin data directory on an encrypted drive Use the third-party disk image encryption program of your choice to create and mount an encrypted disk image of at least 5GB in size.This procedure stores the entire block chain database with the wallet.dat file so the required size of the encrypted disk image required may grow in the future.Locate the Bitcoin data directory, and copy the directory with all contents to the encrypted drive.For help finding this directory, see Locating Bitcoin's Data Directory.

Create a Windows shortcut that starts Bitcoin with the -datadir parameter and specifies the encrypted drive and directory.For example, if you installed Bitcoin in the default directory, mounted your Bitcoin encrypted drive as E:\, and stored your Bitcoin data directory on it as Bitcoin, you would type the following command as the shortcut Target: C:\Program Files\Bitcoin\bitcoin.exe -datadir=E:\Bitcoin Open Bitcoin's settings and configure it NOT to start automatically when you start Windows.This is to allow you to mount the Bitcoin encrypted disk image before starting Bitcoin.Shut down Bitcoin, and then restart it from the new shortcut.After doing this, any time you want to use Bitcoin, you must first mount the Bitcoin encrypted disk image using the same drive designation, and then run Bitcoin from the shortcut that you created, so that it can find its data and your wallet.Your wallet.dat file is not encrypted by the Bitcoin program by default but the most current release of the Bitcoin client provides a method to encrypt with a passphrase the private keys stored in the wallet.

Anyone who can access an unencrypted wallet can easily steal all of your coins.Use one of these encryption programs if there is any chance someone might gain access to your wallet.There is also a list of open source encryption software.Decrypting and encrypting the wallet.dat every time you start or quit the Bitcoin client can be tedious (and outright error-prone).If you want to keep your wallet encrypted (except while you're actually running the Bitcoin client), it's better to relegate the automation to a small shell script that handles the en/decryption and starting up Bitcoin client for you (Linux and OSX).There is also a method to print out and encrypt your wallet.dat as a special, scannable code.See details here: WalletPaperbackup Brute-force password cracking has come a long way.A password including capitals, numbers, and special characters with a length of 8 characters can be trivially solved now (using appropriate hardware).The recommended length is at least 12 characters long.

You can also use a multi-word password and there are techniques to increase the strength of your passwords without sacrificing usability.The Usability of Passwords However, simply using dictionary words is also insecure as it opens you up to a dictionary attack.If you use dictionary words, be sure to include random symbols and numbers in the mix as well.If you use keyfiles in addition to a password, it is unlikely that your encrypted file can ever be cracked using brute-force methods, even when even a 12 character password might be too short.Assume that any encrypted files you store online (eg.Gmail, Dropbox) will be stored somewhere forever and can never be erased.Make sure you pick at least one character in each group: You might want to read What is your way to create good passwords that can actually be remembered?and XKCD #936: Short complex password, or long dictionary passphrase?Backing up your wallet is not necessary if you use a wallet with implemented BIP 0032 (hierarchical deterministic wallet).

Today, only TREZOR, Electrum and CarbonWallet fully support BIP 0032.For advise on the backup process see Backing up your wallet.In most operating systems, including Windows, Linux, and Mac OS X, simply deleting a wallet.dat file will not generally destroy it.It is likely that advanced tools can still be used to recover the wallet.dat file, even after it has been deleted.The Linux shred command can be used to overwrite the wallet file with random data prior to deleting; this particular copy of the file will then be practically impossible to recover.Using shred (and similar tools on Windows) however does not guarantee that still other copies don't exist somewhere hidden on your HD.That will depend on your system configuration and what packages you have installed.Some system restore and backup tools, for instance, create periodic snapshots of your filesystem, duplicating your wallet.dat.In Mac OS, the equivalent of shred is srm (introduced in Leopard).Using the Finder to remove files, clicking "Secure Empty Trash" in the Finder menu will shred the contents of the trash can.

As with any OS this doesn't guarantee that there are not other copies elsewhere on your system.For Windows, the built-in command cipher /W will shred all previously-deleted files.CyberShredder can securely deleted individual files.Thus far, this article has been discussing the security of a wallet file for Bitcoin-Qt or bitcoind that is under your sole control.Online wallets have a number of pros and cons to consider.For example, you can access your wallet on any computer in the world, but you are essentially storing your private keys or wallet with the provider of the online wallet.Depending on the level of security of such service, your bitcoins may be lost if the service is compromised.The invention of hardware wallets makes it possible to use online wallets in a more secure manner.A hardware wallet keeps your private keys apart from the computer and internet.) then does not need to store any sensitive data (private keys, passwords or email addresses) and only serves as tool for broadcasting transactions signed in the hardware wallet out to the blockchain.