If it is the “traditional” Coinbase exchange (w/”KYC”), then Coinbase generated your private key and they control it/know it....you don’t want a copy of that key. If you are referring to the newer “Coinbase Wallet” (formerly the “Bread Wallet” then bought out by Coinbase) then yes your private key is private. But most people are using the traditional Coinbase product that retains your private key on their servers and is subject to hacking, business failure, etc.. (i.e. FTX, Mt Gox, etc., etc.)
Further info.:
From Coinbase: “A custodial wallet is a type of wallet where a third party holds the private keys on your behalf to manage your funds. Using a custodial wallet usually requires you to provide certain documents as part of a KYC (Know Your Customer) process, which is designed to verify the identity of customers and ensure their authenticity.
In the case of your Coinbase.com account, Coinbase acts as the custodian.”
More:
https://cointelegraph.com/news/how-to-store-crypto-assets-in-a-self-custodial-wallet
https://bombthrower.com/how-to-move-your-bitcoin-off-of-coinbase-into-a-self-custody-wallet/
https://decrypt.co/116349/how-move-bitcoin-ethereum-crypto-self-custody
https://www.forbes.com/sites/digital-assets/2023/04/05/beginners-guide-to-bitcoin-self-custody/
I just transacted my bitcoin last night from coinbase to my address. I created the private key and corresponding address using bitaddress.org so it is my private key only known to me.
If you are referring to the newer “Coinbase Wallet” (formerly the “Bread Wallet” then bought out by Coinbase) then yes your private key is private
That's probably where we are not synced up. I don't have a coinbase wallet, never did and never will. I simply log into coinbases's website and transact. What I did last night is log into coinbase, transact a chunk of my bitcoin held by them to an address that I created last night from a private key that I created last night
I didn't need any wallet to generate a private key. Bitaddress.org lets me create private keys and calculates the corresponding address. There's no wallet involved although some people refer to what I created as a paper wallet.
From Coinbase: “A custodial wallet is a type of wallet where a third party holds the private keys on your behalf to manage your funds. Using a custodial wallet usually requires you to provide certain documents as part of a KYC...
Yes, that's all correct. Coinbase holds my bitcoin in their wallet (of sorts). IOW, they control various private keys with a lot of bitcoin associated with them. I own nothing in reality but in their accounting system there's a ledger entry with how much bitcoin I allegedly "own".
You have pointed it out many times, when coinbase or anyone else has the private key they have the bitcoin and you have nothing but a promise. But last night I changed that for some of my bitcoin. On their website I transacted from their holdings that are "mine" to an address that I created from a private key that I created. Coinbase (and the feds) know that address. But only I know the private key. It's in my phone (optional) and on a piece of paper in my safe (essential). So that bitcoin is now really mine.