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Bitcoin => Bitcoin Discussion => Topic started by: Apu2014 on June 15, 2021, 11:42:23 AM



Title: Bitcoind sender proof
Post by: Apu2014 on June 15, 2021, 11:42:23 AM
is there anyway i can proof that this transaction is send by me? any code or something which is available only for sender, not public. like i can give him this code to confirm him that i am the actual sender?


Title: Re: Bitcoind sender proof
Post by: AB de Royse777 on June 15, 2021, 11:44:10 AM
is there anyway i can proof that this transaction is send by me? any code or something which is available only for sender, not public. like i can give him this code to confirm him that i am the actual sender?
Yes, if you own the private key then you can sign the address and prove that the sent amount was sent from this address.

Check this topic: https://bitcointalk.org/index.php?topic=990345.0


Title: Re: Bitcoind sender proof
Post by: Lucius on June 15, 2021, 01:27:13 PM
Apu2014, maybe just to explain to you a little bit what Royse777 wrote, which means if you use an online/custodial crypto wallet you won't be able to sign a message proving that you are its real owner. What I know is that such an option was available at blockchain.com (https://support.blockchain.com/hc/en-us/articles/210353833-What-is-message-signing-and-how-can-I-do-that-) (I'm not sure if that's the case yet), but only for imported addresses with the remark that it will be enabled for all addresses in the future.

In other words, if the address you want to prove ownership of is part of a crypto service like Coinbase or Binance, then you won't be able to do it - it actually belongs to that service, and you just use it for your transaction.


Title: Re: Bitcoind sender proof
Post by: bitmover on June 15, 2021, 08:53:17 PM
is there anyway i can proof that this transaction is send by me? any code or something which is available only for sender, not public. like i can give him this code to confirm him that i am the actual sender?
Yes, if you own the private key then you can sign the address and prove that the sent amount was sent from this address.

Check this topic: https://bitcointalk.org/index.php?topic=990345.0

Also expanding Royse777 answer, a signed message is a cryptography proof that you control that address.

You will send a message like this (if you follow the steps from the above tutorial).

Code:
-----BEGIN BITCOIN SIGNED MESSAGE-----
Hi. I am Apu2014 and I send John 0.02 bitcoins from this address
-----BEGIN SIGNATURE-----
1HZwkjkeaoZfTSaJxDw6aKkxp45agDiEzN
G/bjFN56rbA1KsJ5Ed6YRXt2UV2nIfNz2wXkvqOylL3zYfiivs+RSAS8coOlCfjcpwce0o+9h0Xw57DPlJnDUBY=
-----END BITCOIN SIGNED MESSAGE-----

You can then send this message to him, by email or whatever, and he can verify that this message is valid or not in most bitcoin wallets or online here: https://brainwalletx.github.io/#verify

The Signature will only be valid if you control the private key of the address mentioned.

(This is a throwaway address that I generated in https://brainwalletx.github.io/, just to make an example.


Title: Re: Bitcoind sender proof
Post by: Upgrade00 on June 15, 2021, 09:08:17 PM
is there anyway i can proof that this transaction is send by me?
This would depend on the means of initiating the transaction. If it was done through a non custodian wallet, you could sign a message proving you own the address, as others have suggested.

However, if you use a custodian service and do not own the private key, it becomes a bit more tricky as you do not own the private keys and cannot prove ownership of the wallet (cause you do not own it)
Screenshots of your email confirmation of the transaction seems your best bet, except it isn't full proof as screenshots can be faked, another option would be to send a small (pre determined) amount to some other of your address, to show you are the one sending from that address/account.


Title: Re: Bitcoind sender proof
Post by: sheenshane on June 15, 2021, 10:51:23 PM
All said above was right, all open-source Bitcoin wallets can able to sign messages, and even a web wallet that you don't have a private key but still you can sign a message on it.  An example is the Blockchain.com wallet is also capable of signing messages.

Screenshots of your email confirmation of the transaction seems your best bet, except it isn't full proof as screenshots can be faked, another option would be to send a small (pre determined) amount to some other of your address, to show you are the one sending from that address/account.
All of these are prone to be faked as well.  Dont trust if anyone if there's someone who shows proof of Bitcoin ownership through a screenshot and or even in a short video clip, it could be modified using photoshop.  The best is to sign a mesage as solid valid proof.