Topic: Help with wallet.dat? (Read 2070 times)

I do get that, as I only have a blackcoin wallet, and wanted to know the best way for me to back up the wallet.dat file from the blackcoin-qt that is currently downloaded on my macbook. I guess I'm mainly worried I'll do it wrong and say my laptop gets stolen, I buy a new one, and then I try to get the wallet.dat from my flash drive but say it's corrupt or not there or I messed it up. I don't want my coins to be gone forever.

I will definitely look into a bitcoin wallet in the future, but I figure for now I just need to focus and understand one, haha. 

blackcoin-qt is just for blackcoins.

bitcoin-qt is for bitcoins.

There are other wallets to consider for bitcoin as well.  It wouldn't be a bad idea to investigate each and decide which one best suits your needs.  Some are more convenient, others have additional security features.  Here's a good list to get you started:

• Armory
• Bitcoin-Qt (also known as Bitcoin Core)
• Electrum
• MultiBit
• https://blockchain.info/wallet

I haven't ever downloaded the bitcoin-qt.  I just have like .5 bitcoin in Coinbase.

I did download the blackcoin-qt which I'm trying to figure out how to backup in case something happens to my laptop.

You mean bitcoin qt right? lol. Yeah, you should consider it since being one of the first desktop wallets.

Just make sure you update to the latest 0.9.1 like the top forum notification states.

is that the same premise for blackcoin-qt? I actually don't have one for bitcoin, but thought I should download it (I literally have like .5 coin so didn't ever feel the need).

If you are using Bitcoin-Qt, and creating backups, it is important to be aware of how it works.

Bitcoin-Qt pre-generates the next 100 addresses that it will use and keeps them hidden from you in the wallet.dat.

This means that if you create a backup, and then choose the "New Address" button a few times, you can still recover your entire balance from the backup that you have (since the new addresses all came from that pool of addresses that were in the wallet.dat when you backed it up.

Each time the wallet grabs one of these pre-generated addresses, it creates a replacement to add to the end of the list.  Obviously these replacement addresses aren't in your backup.

Therefore, if you go through more than 100 addresses since your last backup, then you will be using addresses that aren't in the backup copy, and will no longer be able to recover your balance.

Another thing to be aware of is that the wallet uses one of these pre-generated addresses every time you send a transaction from the wallet to anywhere.  The wallet needs to send the change from the transaction back into the wallet and it does so by getting a new address from the pre-generated list each time.  It doesn't show this address to you anywhere, since it's jsut for change, but it keeps track of it for you in the wallet.dat and it uses up one of the 100 pre-generated addresses.

Therefore, you want to keep an estimate of both how many addresses you've created with the "New Address" button AND how many transactions you have SENT.

It's a good idea to have multiple backups stored in multiple locations just in case the most recent backup is damaged or otherwise unusable.

In general I advise creating 1 new backup every time your estimated total addresses used up is approximately 25.  Then keep the 3 most recent backups.  That way your backups are staggered over time (in case something recent damaged the wallet.dat file before you made the most recent backup, and you'll have 3 backups that can all recover the complete balance.  You'll also have a bit of "Wiggle room" in case you miscount in your estimate.

Thank you so much!

I am wanting to backup my wallet in case say, my laptop got stolen or something. I want to have the ability to get a new computer and get all my coins back. I think that link was given to someone (maybe me?) here in the beginners forum and I didn't realize it was out of date! It is all making way more sense now why those directions are so different than simply clicking 'backup'.

That really depends on what you're trying to accomplish.  The advice at that link isn't exactly "bad" advice, but it isn't useful advice for a lot of people.  It's also a bit outdated.  It isn't necessary to shut down your wallet and find the file on your hard drive.  The wallet now has a "Backup Wallet" option in the menus.


https://en.bitcoin.it/wiki/Data_directory#Mac

If you want to manually copy the file from that location, you need to make sure that the wallet isn't running.  Also, if/when you want to recover the wallet.dat file you'll need to make sure that the wallet isn't running before copy the backup back to that location.


Yes, that will work as well.  You can do that while the wallet is running (obviously). Either method results in the same file being stored on the USB.


Correct.


Yes.


If your computer was online when you created the wallet, or has ever been online with that wallet.dat file, then there really isn't much benefit to being offline while you copy it to the USB.  If you are very concerned that a hacker might have remote access to your computer, then you can reduce your exposure by being disconnected from the internet BEFORE the wallet.dat is created in the first place.  Then copy it to the USB, and delete it off the computer.  In that way, nobody has access to the file from the internet at all.


This depends on what you are trying to accomplish.  If you just want addresses where you can receive bitcoins, you can write down the addresses before backing them up, and then delete the original file from the computer (AS LONG AS YOU ARE 100% CERTAIN THAT YOU HAVE A GOOD BACKUP). Since the wallet.dat is not on a computer anywhere, nobody can access it to steal the bitcoins unless they get access to the USB.  However, this adds significant inconvenience if you want to be able to send bitcoins from the wallet on a regular basis.  The wallet.dat needs to be on the computer in the correct directory any time you want to send any bitcoins.  Once you've put the wallet.dat on the computer (to send bitcoins somewhere), you've lost the benefit of having a wallet.dat that has NEVER been connected to the internet, so if you want that benefit, you have to repeat the process again creating a new set of addresses, and sending all your bitcoins from the old wallet.dat to the new one.

As I said, if you plan on only receiving bitcoins and long term storage of them, this method is ok.  If you want to be able to send the bitcoins occasionally, this isn't such a great plan.


Correct.


When you want to be able to send any bitcoins from the wallet.dat, you need to make sure that the wallet program is not running.  Then you need to copy the wallet.dat file from the USB to the directory indicated above.  You need to make sure that you name it "wallet.dat" (all lower case) when you put it there.  The wallet program specifically looks for a file with that filename in that location.


You'll get much better advice if you explain what you want to accomplish, rather than asking how to follow some instructions that you found on the internet.

It depends on the # of transactions that are sent. If its more then 80, then you need to back up periodically every week.

I dont want to give you a long prevention list, but if you lost the balance already wondering with the wallet.dat file like most do, its because few mention about # of transactions take a vital role.


Explanation: Alice generated enough change addresses to overflow the original pool of 100. On the 100th spending transaction, Bitcoin-Qt moved Alice's change (which happend to be her entire balance) into an address not in the backup. Restoring the backup only restored empty addresses.

Recovery: Even if a hard drive can't boot an operating system, individual files can still be recovered. 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.

Prevention:

Count the number of manually-created addresses and spending transactions since your last backup. If this number is greater than about 80, back up again. Weekly backups might be enough for most users.
Set a very high value (e.g., 10,000) for the -keypool option, either as a command line parameter, or in the bitcoin.conf file.
Switch to a deterministic wallet.

Wanted to follow up.

I read this: http://www.cryptobadger.com/2013/05/guide-bitcoin-wallet-security/

and wanted to confirm steps 6 and 7 - it's not just for litecoin, but for all qt clients?

I bought the 3 USB flash drives it talks about in step 6. It then talks about Windows and Linux and how to find your wallet file, but I am on a Mac. Can anyone help me locate this? To add, I'm not sure what it's saying here exactly because it tells me to shutdown to client to save the backup from that location. But what I think I'm wanting to do is from the blackcoin client drop down menu, click "Backup Wallet" and save it to my usb flash drives. Yes? So then I can't shut it down first? They're talking about a different method to backup my wallet.dat file? And I should be offline to backup to the flash drives? And then I want to delete it (step 7) from my computer?

And to confirm, when I go to 'open' my wallet.dat file, my mac says application can't be found. So I can't open the file. Is this right? So how do I use it?

I just want to make sure I'm doing this right. Thanks again.

He said very good, very happy for your problems can be solved.

Thanks all!!

And Danny - very much appreciate the breakdown of my questions. I am definitely terrified!!  So I want to make my coins as secure as possible while also keeping them safe from myself and my own errors, haha.

Yeah, it's pretty long, you have to be patient.

For most cryptocurrencies a wallet is a collection of private keys that give you access to the coins that have been sent to specific addresses.  The wallet usually also provides a list of those specific addresses for which it has the private keys so that you know where to send coins (or where to have others send coins) such that you can access them.  In many cases this is handled by software (although there are also paper wallets and brainwallets).  When the wallet is software, it generally includes additional useful features such as but not limited to an intuitive method for creating, signing, and broadcasting transactions, as well as an address book of addresses that you been given to send coins to and a history of transactions sent and received.


The user interface tends to be intuitive for most people. Some wallets have better documentation than others.


Well, they are significantly different in that they each manage a different cryptocurrency.  In addition, the developers of each altcoin have different levels of commitment to thier pet projects.  As such, some do a better job of keeping their software up to date with the latest features and bug fixes than others.

There are also multiple types of wallets for some cryptocurrencies. As an example, bitcoin has Electrum, MultiBit, and Armory in addition to Bitcoin-Qt.  While each of those wallets allows you to control bitcoins, the wallets each have their own set of features, and quirks.


http://en.wikipedia.org/wiki/Qt_%28software%29

I suggest that you read the whitepaper that first described how a decentralized cryptocurrency could work through the use of proof-of-work for a distributed consensus.  It is generally referred to as the "Satoshi Whitepaper", or the "Bitcoin Whitepaper".  You can find it here:
https://bitcoin.org/bitcoin.pdf

The blocks of transactions form the blockchain which is the consensus agreement on the ordering of transactions that solves the double-spending problem.


People do hack into these wallets.

With a wallet such as this, you get to be responsible for keeping your own money safe.  You don't have to trust someone else and hope that they know what they are doing. It is up to you to make sure that you have sufficient security in place.

On the other hand, an exchange is a very publicly known place with a huge number of coins.  There is therefore a lot of incentive for hackers to spend a lot of time and a lot of money finding ways to hack in, and they know where to look.  A piece of software running on your computer is much less likely to draw the attention of a hacker who can find more valuable targets elsewhere.

An exchange also has to have automated methods of transferring balances between users, and automated methods of withdrawing your balance.  Hackers can take advantage of these automated methods.

It is good that you are scared.  Hopefully that fear will act as an incentive to take the time to learn about the various methods available to you for securing your money.


That doesn't sound right?  "Encrypt Wallet" should have asked for a password and then should have encrypted the private keys with the password that you provided.  It shouldn't have created a backup.  Encrypting the wallet is a good idea.  It means that if a hacker does manage to get a copy of the wallet data files, they won't be able to use the private keys to take/spend your bitcoins unless they also managed to get a copy of your password.


That sounds like you clicked on "Backup Wallet".  If so, then this file should contain all of your private keys (along with some other useful information about your transactions).  If your existing wallet data should be lost or damaged, you can re-install the software and replace the "wallet.dat" file in the data directory with the "backup.dat" file (rename it to wallet.dat when you put it in the data directory).  This will allow you to re-gain access to your coins.  You should create a backup on a regular basis (if the sum of the number of receiving addresses created plus the number of transactions sent exceeds 25, it's probably a good idea to create a new backup), and store a few recent copies offline somewhere secure.

Looks like you have misunderstood OP. He was talking about blackcoin, which is an altcoin

First of all your using a uncommon wallet, and it might be a heavy wallet.
All wallets contain a copy of the blockchain which is essential for the bitcoin network to run.
The 'blocks of transaction' might be your version of the blockchain.
Currently Blockchain is ~13Gb so I would recommend you to use a light wallet such as Multibit, these wallets are secure and doesn't take up as much space as the Blackcoin wallet you're using.
Your better off using the more common wallets: https://bitcoin.org/en/choose-your-wallet.
Don't use web based wallets because they can be hacked.
To back up your wallet you just have to export it to a preferably safe location
Import a wallet to utilize it after you've export it
Good luck 
BTW the first wallet startup is always the longest

Hey all, questions on wallets!

I downloaded the official blackcoin wallet and transferred my coins from Mintpal in after the Crypto Rush news. Honestly I didn't really read up on what it was before I made the transfer, just that it was safer, so moved them sort of in a panic. Now I'm trying to figure out what a wallet is and what I just did. Is there any kind of step-by-step, easy to understand tutorial that can break things down to explain what these wallets are and how they work? Are they all different (like bitcoin-qt vs blackcoin-qt etc)?

I see the wallet on my desktop. I tested with one coin to start, which worked, so transferred the rest. I see my coins in there. But what exactly is a "qt"? What are "blocks of transactions" that I'm downloading? It scares me because it doesn't seem that secure if it's connected to the internet...how do people hack into exchanges and not into one of these wallets?

And how do I back up this wallet? I clicked "encrypt wallet" and it downloaded as something like 'blackcoin wallet backup.dat' but I can't open the file (says 'there is no application to open the document'). What is this, and how do I utilize this, should something happen to my computer?
 
Thanks so much!