Hello.
Bitcoin and crypto currencies are well known for its security.
I also agree on it as no third party is required and also because it is based on P2P transaction.
But, what if some one knows our wallet address because I once sent him some bitcoins.
And after some time, he was willing to hurt me if I send some btc to one of my friend [his enemy]?
It happened with me.
He knows my address and will hurt me if I send any coins from my wallet to any other wallet.
He started checking my recent transactions and will ask me to whom I send bitcoin and why?
Is there any way we can hide our wallet?
But, it will create problem in transactions, right?
Other than the fact that I think you might need to call police, I have another suggestion for you.
You can tell your friend that your wallet was hacked or that you decided to send your BTC to a new address for security reasons.
Since you already sent BTC from that address before, your public key is on the blockchain now.
In case there are quantum computers big enough to break your key or that public key cryptography is broken in the future, your bitcoins would not be as safe as they would if you sent them to a new address.
This new address can be of your friend and he could send you change on some other Bitcoin address your other friend doesn't know about.
That is if you trust that friend and doesn't want to give him all of your bitcoins from that address.
You could do some other stuff as well, of course, but all of it will be obvious that you moved those bitcoins.
Blockchain simply needs to know if some address has bitcoins to spend or not. (not literaly but close enough)
Lightning network is already being considered safe enough to be used on mainnet and I think there is a new Eclair Android app for LN.
This is a good excuse to lock your funds in a payment channel and use it to send your friend some bitcoins with basically no fee.
Your other friend will see that your bitcoins are locked in a payment channel (if he knows what that looks like), but he will not be able to see whether or not you spent some of your bitcoins and where they went. Only upon closing a channel there will be obvious lack of funds, but still no known destination for them . You don't need however to ever close your payment channels if you don't want to.
You could also, of course, use an excuse that you want to switch to a new bech address format and have cheaper transactions in the future.
And send your bitcoins to your firend's bech address.
