What does the wallet.dat file do?

[timk225]

From what I have seen, the wallet.dat file in my BitCoin wallet is pretty much everything.  It seems like it is the file containing the identifying information so I can see how many BTC I have in my wallet address.  The blockchain itself is also important, but the wallet.dat file seems to be the one that says "Everyone else has "X" number of BTC, but you have "X" number of BTC in this wallet".

Right, or does it do something else?

When backing up the wallet, do you only need to copy this wallet.dat file, or other files as well?

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[ledmaniak]

The data in wallet.dat only proves that you are the actual owner of the coins send to a certain address. Even when wallet.dat has never seen the blockchain, you can still send bitcoin to it and retrieve them when you open bitcoin-qt with the wallet.dat.

[steve15]

The wallet.dat file is like your personal wallet in real life, it proofs you own it.
Your real life wallet has no data about who whas what amount right?

When you backup, you just need that file, nothing else. All the rest gets synced with the blockchain

[timk225]

I recently changed hard drives in my desktop PC, and redownloaded the BTC wallet and blockchain to it, and it reported 0 coins.  Then I Copy and Pasted in just the wallet.dat file from my backup copies, nothing else, and BAM it showed my coins.  

So I guess that's the important part.

[cp1]

The blockchain says:

Address 1 has 10 BTC
Address 2 has 5 BTC
Address 3 has 0 BTC
Address 4 has 15 BTC
....

wallet.dat says:
The private key to address 2 is:  lfkjlkjfsdskdl

Whoever controls that wallet.dat controls the 5 BTC in address 2

[triwebb1]

Every address is like a door with a mail slot.  Anyone can drop coins in the slot from outside, but to get access to the coins that have been dropped in the slot you need the key to the door.  The wallet.dat file contains the key to the door.  If you lose that key you'll never be able to get the coins inside.

[roslinpl]

From what I have seen, the wallet.dat file in my BitCoin wallet is pretty much everything.  It seems like it is the file containing the identifying information so I can see how many BTC I have in my wallet address.  The blockchain itself is also important, but the wallet.dat file seems to be the one that says "Everyone else has "X" number of BTC, but you have "X" number of BTC in this wallet".

Right, or does it do something else?

When backing up the wallet, do you only need to copy this wallet.dat file, or other files as well?

you make a copy only of wallet.dat

you can print it as well cut a paper on two and hid it in two different places known only for you.

So - after you backup wallet.dat you can uninstall wallet and after some time install and recover your keys from wallet.dat file.