how to import old bitcoin address in bitcoin core..

The bitcoin core only allows to create new addresses. How can i add my old bitcoin address in the bitcoin core. Also why does electrum wallet does not take old 2009 bitcoin private key. Do i have to change it to some other format. The wallet was mined in feb 2009. Please help. Cheers.
Japs

If you have the private key you can import it on Bitcoin core through command.
Do you have the private key?

I heard that old doesn't work on Electrum but can you tell us what is your backup key first character?

What I think is that if the old address doesn't work on Electrum try to convert them using this tool https://www.bitaddress.org/
Then go to wallet details and paste the private key it should show two different wif private key compress and uncompressed private key.
Use the uncompressed private key and import it to Electrum.

That's because Electrum doesn't support P2PK (Pay to Public Key) outputs and if it's from 2009, then it's definitely P2PK.
It doesn't have an address, instead the public key itself.

Bitcoin core will work, you can import your private key using the command: importprivkey
and the funds will be added to your wallet after the rescan.

Well it starts with K so i presume 5 is needed to add on it. But so it is confirmed that electeum does not take old bitcoin private key. Also how do i add my old address on bitcoin core latest.. it only has button saying create new address.

Quote from: japanese2212 on May 01, 2021, 04:28:42 PM

Well it starts with K so i presume 5 is needed to add on it. -snip-

Oh, if it's a WIF private key and a with a compressed pubkey flag, then you're likely getting the date wrong.

Read this thread and see if your private key is similar to any of the formats: [overview] Recover Bitcoin from any old storage format.
It also contains the necessary info on how to restore them.

Quote from: japanese2212 on May 01, 2021, 04:28:42 PM

Well it starts with K so i presume 5 is needed to add on it. But so it is confirmed that electeum does not take old bitcoin private key.

No, you do not need to add a 5 on to it, and doing so will create an invalid key.

A private key which begins with "K" is probably a compressed WIF key, and therefore, should have 52 characters. Please count the characters in your private key to ensure it has 52 characters. Electrum will absolutely accept these private keys. Have you tried to import it to Electrum? If it generates the wrong address type, then you may need to append one of the following to the private key, depending if the address you are trying to access begins with "1", "3", or "bc1" respectively:

Code:

p2pkh:Kyourkeyhere
p2wpkh-p2sh:Kyourkeyhere
p2wpkh:Kyourkeyhere

Quote from: japanese2212 on May 01, 2021, 04:28:42 PM

There is no button to press, you have to do it manually through the consoler. So, goto the console: "Window -> Console"

Then type: importprivkey YOUR_WIF_PRIVATE_KEY_GOES_HERE

Quote from: japanese2212 on May 01, 2021, 03:31:08 PM

Also why does electrum wallet does not take old 2009 bitcoin private key. Do i have to change it to some other format.

You cannot import a private key into a "standard" Electrum wallet that was created with a 12 word seed. The reason for this was that the dev's felt that it was "dangerous", as some users might not understand that by importing a private key, it would not be backed up by the 12 word seed... and they might not take adequate precautions to ensure the private key was also backed up manually.

To use that private key in Electrum, you have to create a completely new (and separate) wallet in Electrum (as outlined above using "New\Restore -> Import Bitcoin addresses or private keys"... This will allow you to import your private key. Once you are finished, you will note that the wallet type will be displayed as "[imported]"... note that you will need to ensure that you have the imported private key(s) and/or wallet file safely backed up.

What about for 51 character. How I add bitcoiin address to bitcoin core...there is no option

Quote from: japanese2212 on May 11, 2021, 04:37:11 PM

What about for 51 character.

A 51 character address is an uncompressed WIF key and should therefore start with a "5". If you have a 51 character key which starts with a "K", then the likelihood is that you have a compressed WIF key with one character missing. If neither Bitcoin Core nor Electrum are accepting your key, then there is a good chance that this is the case. You could also try putting your key in to this tool (https://iancoleman.io/bitcoin-key-compression/) after you have downloaded it and ran it offline, and see if it tells you if it is a valid key or not. You will then need to use a tool such as this one - The FinderOuter, a bitcoin recovery too - to find your lost character.

If you want to import an address, then the command is simply importaddress.

I haven't tied on bitcoin core yet. Will it work offline if import private key. Back in 2009 all I had to do was type the private key and add 5 in the beginning. It used to work back then.. I will try and see if it works once again

Quote from: japanese2212 on May 11, 2021, 07:53:13 PM

It would work if your bitcoin core is not pruned or if it's pruned mode you must disable it before you import.

Here's the way to import it

First, make sure it was not pruned mode enabled to check that find the bitcoin.conf or go to settings just uncheck it on the settings or remove prune=x from bitcoin.conf.
Next, go to console and use this command.

Code:

importprivkey yourprivatekey

If your wallet is passphrase protected you will need to type this command first before you can able to import it.

Code:

walletpassphrase mywalletpassword 60

Then use the import command again

Take note it won't show any balance until your bitcoin fully sync and rescan.

For me, If you want to transfer the balance of your old wallet right away the best option is to import it to Electrum if it started with 5, not K or L then you will need to convert it using bitaddress like what I said above.

Quote from: songchunlai on June 07, 2021, 03:36:31 AM

How about KMN5 or 5KMn.

Is this an answer to the OP or your own question?

If the it's a question, please include more info about the issue so people can help you better, better if you open a new thread.
If it's your answer, the earlier posts already have more info about what the WIF private key looks like.