understanding import/sweep blockchain

[lovethepirk]

I am new and I am catching onto the knowledge slowly.

I have a:
coinbase account with public key(I can't find a private key)
blockchain account with public key(I can't find a private key)
paper wallet with public and private key.

1st I thought you needed a private key to send money....why doesn't coinbase or blockchain have a private key?
2nd I want to move my paper wallet into my blockchain account so I can spend it.  If I import my key do I retain complete control over that money still?  ie. If blockchain goes bankrupt am I still in control over those monies b/c I imported vs sweeping?

Thanks.

[jbrnt]

I don't use coinbase, so cannot answer that for you.

Blockchain wallet do provide private keys. You can access those keys encrypted or in plain text format in the import/export section.

If you import your paper wallet into blockchain wallet, you still have complete control over that particular address, but so do hackers who somehow hacked into your account. Once you import your paper wallet keys into blockchain wallet, it is made "public" in an encrypted form. Hacker can access your funds if they brute force your password.

If blockchain.info goes "bankrupt" you still have control over the funds in your addresses if you have your private keys. You can export them manually, or backup regularly via email.

Here is simple guide about accessing your coins if blockchain.info is offine:
https://bitcointalk.org/index.php?topic=594570.0

[lovethepirk]

There are three distinct choices for blockchain:

1) Watch
2) Sweep
3) Import


If you choose sweep and the next day blockchain shuts down and is bankrupt(wiped off the face of the planet forever), are your bitcoins lost and unrecoverable because they got swept into the public key issued by blockchain?

[onemorebtc]

coinbase has always the private keys for your deposit address.
they need to keep it private so that you are unable to move funds using other wallets and only can withdraw through their website.

blockchain.info is a wallet (like bitcoin-core) where your private keys really belongs to you. and only if you control the private keys they are your coins (as seen with mtgox recently)....

[jbrnt]

If you choose sweep and the next day blockchain shuts down and is bankrupt(wiped off the face of the planet forever), are your bitcoins lost and unrecoverable because they got swept into the public key issued by blockchain?

They are swept into a new address or one of your old addresses in your blockchain wallet. If you have the private keys to all your addresses in blockchain wallet. You can import the private keys into another blockchain client, such as Multibit and Electrum, and transfer all the coins to another address.

Therefore, I can not stress enough to BACKUP all your private keys all the time.

[Zebra]

I am new and I am catching onto the knowledge slowly.

I have a:
coinbase account with public key(I can't find a private key)
blockchain account with public key(I can't find a private key)
paper wallet with public and private key.

1st I thought you needed a private key to send money....why doesn't coinbase or blockchain have a private key?

Coinbase works like a bank.

When you deposit 10000 USD in your bank account, you no longer directly control that 10000 USD. Instead you get a 10000 balance on your bank account.
Similarly, you can't control your bitcoin directly on your coinbase account, and so only coinbase (not you) has the private key.


For blockchain.info, you should be able to find your private keys in the "Import / Export" tab.

[Zebra]

Therefore, I can not stress enough to BACKUP all your private keys all the time.

+1.

I would also suggest you to encrypt the file with long password, and make multiple backups just in case your HDD fails on the same day blockchain.info goes down.

[lovethepirk]

So what is the difference with Import vs Sweep?

Sweep moves the money it looks like and import brings in the public key.  Why would one choose one over the other?

[DannyHamilton]

So what is the difference with Import vs Sweep?

Sweep moves the money it looks like and import brings in the public key.  Why would one choose one over the other?

Use sweep if someone else knows the private key.

For example:

You are buying bitcoins from someone.  You arrive with cash in your hands.  They arrive with a paper wallet that is already loaded with the amount of bitcoins that you are purchasing. You have know way of knowing if they kept a second copy of the paper wallet.  If you just import, then you and they both still have access to the bitcoins.  They could spend (steal) them before you get around to using them.  If you sweep, then they get moved to a new address with a new private key, that way they can't still access the bitcoins with the private key from the paper wallet.

[Harley997]

I am new and I am catching onto the knowledge slowly.

I have a:
coinbase account with public key(I can't find a private key)
blockchain account with public key(I can't find a private key)
paper wallet with public and private key.

1st I thought you needed a private key to send money....why doesn't coinbase or blockchain have a private key?
2nd I want to move my paper wallet into my blockchain account so I can spend it.  If I import my key do I retain complete control over that money still?  ie. If blockchain goes bankrupt am I still in control over those monies b/c I imported vs sweeping?

Thanks.

For Coinbase: you do not control your private keys. Coinbase will use it's own private keys to sign a TX to send funds to an address that you specify assuming that you have funds available. If coinbase were to fail in some way then you would lose your funds

For Blockchain: you are in control of your private keys. If you have an email address attached to your account then you will receive a backup of your keys anytime your wallet changes. Since blockchain's wallet is open source even if blockchain were to fail/go bankrupt there could be other services that are compatible with the encrypted backups. With that being said there would probably be a lot of scams trying to steal private keys.