How to prove to someone that an Bitcoin address (or UTXO) belongs to you?

 Are there  (ZK) methods to prove it?

 Does anyone know?
 

According to the example of the Providing a deposit in the bitcoin wiki, https://en.bitcoin.it/wiki/Contract#Example_1:_Providing_a_deposit

I found that even if the user is malicious, the malicious user can't be punished (no loss of money).

Code:

Obviously, if the user turns out to be abusive (i.e., a spammer), the website will not allow an early close of the contract. 

Are there contract methods that can punish the malicious user?

 Had anyone read this paper?  Paper Link: https://eprint.iacr.org/2016/056.pdf

     In this paper, what script is used to verify the blind sign?  I didn't understand.
     In the seventh page of this paper, the transaction T_f needs to meet two conditions.

Code:

1. T[sub]f[/sub] is signed by I and contains a valid blind signature /theta on sn(overlines), or
2. T[sub]f[/sub] is signed by A and the time window tw has expired. 

    I know that Condition 2 uses OP_EQUALVERIFY OP_CHECKSIG and timelock to achieve.
     But how is Condition 1  implemented?  
     Can someone teach me?

    

  How much BTC(at least) does it cost to build a transaction that only contains OP_RETURN(OUTPUT)?

  Is there any information about this?

OS:Windows 10
Bitcoin Core Version:0.16.0

How run multiple nodes in regtest/testnet mode on a single machine?
I want to test.

[Bitcoin Core Version: v0.16.0(x64)]

I started bitcoin core for sync block yesterday, but it always stays in block 1435525 after several hours.
And Bitcoin Core shows that 0 active connection with Bitcoin network.

Bitcoin Core Version: v0.16.0(x64)

Why does Bitcoin Core(testnet) unable to connect to bitcoin network?
Is it possible that bitcoin core has been updated to 17.0 a few day ago? Or other reasons?

[Client info: Not enough funds in the wallet to tumble. Missing about 0.62188671. Denomination is 1.00000000.]

    Do you have unused test bitcoins? IF yes. Could you give me some coins? 
    Please send a little amount of (approximately 0.8B) to 2N464wccQ57yAzY61Gc9pPPYfYxMqQ2nZUt
    I need test bitcoins for development.But some testnet faucet maybe is wrong and I can't get test bitcoins.
    THX!!
 
  Client info: Not enough funds in the wallet to tumble. Missing about 0.62188671. Denomination is 1.00000000.