How somebody can prove that my wallet belong to him?

[JustAsk]

What if i catched some mot****er, who is using one of my wallets - how can i prove that it's mine? 

[Cantsay]

By signing a message with the wallet, if you're referring to a Bitcoin wallet then you can just sign a message proving that you truly own that wallet but for other network like Ethereum and the rest I'm not sure if you can sign with them because I haven't seen any message signed with them ^{although that doesn't mean it's not possible} .
And by the way Op why do you need to prove to people that you're the owner of a wallet? And why would someone else be using your wallet address?

Edit:

Huh.. But we can both signing from my wallet...

*It's not a real situation! It's just a model!

What type of wallet are you using? And how's that even possible to sign a wallet them being I possession of your private key?

Just as @buwaytress suggested just ditch the wallet and create a new one this time use a more reputable wallet like Electrum.

[buwaytress]

Signing from your wallet with an address that belongs to you. Which wallet are you using?

If someone else is actually really using your wallet already, then you'd best ditch your wallet and sweep all your funds out.

[JustAsk]

Signing from your wallet with an address that belongs to you. Which wallet are you using?

If someone else is actually really using your wallet already, then you'd best ditch your wallet and sweep all your funds out.

Huh.. But we can both signing from my wallet...

*It's not a real situation! It's just a model!

[EarnOnVictor]

Your case and question don't portray sincerity and it's incomplete at the same time. Is the wallet custodial or noncustodial? Do you still have crypto assets in it?

Based on these, if you don't have crypto assets in it, why waste your time, go for another wallet for privacy and security reasons. But if you have crypto assets in it and it's custodial, contact your wallet company with your original details for a reclaim. However, if it's noncustodial, signing a known message with your private key will be the most viable way out.

#Update:

Huh.. But we can both signing from my wallet...

*It's not a real situation! It's just a model!

Lol...In this case, it's your carelessness and the person has all the needed information of the wallet. Quit it and move all your coins if you have any, and if still possible.

[JustAsk]

Your case and question don't portray sincerity and it's incomplete at the same time. Is the wallet custodial or noncustodial? Do you still have crypto assets in it?

Based on these, if you don't have crypto assets in it, why waste your time, go for another wallet for privacy and security reasons. But if you have crypto assets in it and it's custodial, contact your wallet company with your original details for a reclaim. However, if it's noncustodial, signing a known message with your private key will be the most viable way out.

Let us make it maximum easy.

We both know seed-phrase. How can i prove that the wallet is mine???

[Justtoons]

It's literally not possible for someone else to be using your wallet unless you have given them your secret phrase or possibly lost them. The only thing to do is to clear your funds and create a new wallet as soon as possible, So you won't loss your coins.

There's nothing there to prove it's your coin we are talking about here are you going to prove that you own an empty wallet or something because definitely he would have swept out your coins  already.so in such case be smart and fast.

[tranthidung]

What if i catched some mot****er, who is using one of my wallets - how can i prove that it's mine? 

If you posted your address somewhere on this forum and now you can sign a message from it, you can prove that you are not only the current owner but likely the initial owner.

However, it is applied if you want to prove that your account is not hacked (aka one of account recovery methods).

If you don't need to prove your account ownership, that step (signing a message does not mean anything) because if they hacked your wallet and stole your fund, they have access to your private key and can sign any message from that wallet.

How to sign a message
Stake your Bitcoin address here
Often, you need to prove ownership of the account with a PGP or Bitcoin signature

You didn't elaborate what you need but I shared these topics to help you understanding more about importance to secure your private key and sign a message as ownership proof. It is necessary when you need to make a trade, your trade partner will ask you to sign a message too.

[Cantsay]

Your case and question don't portray sincerity and it's incomplete at the same time. Is the wallet custodial or noncustodial? Do you still have crypto assets in it?

Based on these, if you don't have crypto assets in it, why waste your time, go for another wallet for privacy and security reasons. But if you have crypto assets in it and it's custodial, contact your wallet company with your original details for a reclaim. However, if it's noncustodial, signing a known message with your private key will be the most viable way out.

Let us make it maximum easy.

We both know seed-phrase. How can i prove that the wallet is mine???

Since you both are in possession of the secret phrase technically the wallet is no longer yours.

The best solution is for your to create a new wallet and let go of the previous wallet.

[mendace]

What if i catched some mot****er, who is using one of my wallets - how can i prove that it's mine? 

I don't understand who you would need to prove it to, but if you are the owner and someone is using your wallet, there are two scenarios: either they have withdrawn all of your funds, and therefore you essentially cannot prove anything, or if they have only moved a few funds, you need to quickly move all of them before it's too late. There's no need to prove anything to anyone; otherwise, what's the point of anonymity?

[o_e_l_e_o]

Let us make it maximum easy.

We both know seed-phrase. How can i prove that the wallet is mine???

You can't.

In the scenario where you both know one or more private keys from the wallet, but only you know the seed phrase, then it is possible to prove that you are the real owner of the wallet by providing a proof (ideally, a zero-knowledge proof) that you are in possession of the seed phrase which was used to derive those private keys, while the other party is not.

In the scenario where you both know the seed phrase, there is no way to prove who was the original creator of that seed phrase.

[OgNasty]

Your case and question don't portray sincerity and it's incomplete at the same time. Is the wallet custodial or noncustodial? Do you still have crypto assets in it?

Based on these, if you don't have crypto assets in it, why waste your time, go for another wallet for privacy and security reasons. But if you have crypto assets in it and it's custodial, contact your wallet company with your original details for a reclaim. However, if it's noncustodial, signing a known message with your private key will be the most viable way out.

Let us make it maximum easy.

We both know seed-phrase. How can i prove that the wallet is mine???

Here is the maximum easy answer. If you both have the seed phrase then the wallet is both of yours.

Explanation being that ownership of an address comes down to who knows the private key and I guess in legal situations who used the key… If you both have the private keys then you can both use them. I don’t think there’s been court cases yet where people dispute the ownership of an address and both have the keys. The only court cases I’m familiar with are the ones where someone is trying to claim ownership without having the keys.

[franky1]

all the responses are people taking the word "wallet" too literal as software..

the OP is talking about if some hacker or ex girlfriend obtained the seed phrase/wallet.dat file thus has possession of the private key..

in which case if they have not already moved the funds out of the keys to their address thus stealing funds away from you. the only option is for you to quickly move the funds to a fresh seedphrase/wallet that uses different keypairs which the other person does not posess

if the funds are gone. and you are trying to take this person to court and you are asking for proof that you owned/created the seed phrase and not them. to claim original ownership, meaning proving they stole your funds
well thats alot harder to prove

unless:
a. the phrases represent words that can clearly be tied to things in your life and not the hackers
EG all 12 words have a meaning towards your hobbies EG your a musician and all words are musical related. and/or have relation to your families hobbies/interests

b. where the stolen funds came from before being sent/deposited to your keys. EG buying coin on an exchange and withdrawn straight to your wallet whereby the exchange has KYC evidence that you bought the coin(though the thief can just claim you donated coins straight to them when you withdrew from the exchange) but would require the thief showing equal proof that the funds were intended for them to spend EG needs conversation logs of you saying you will buy coin and send it to them direct from the exchange

c. by having proof of means, method, opportunity to have got hold of your seed phrase/wallet.dat file. EG you ca link the hacker/thief to a piece of software that trojan horsed your computer with wallet.dat stealing capability or a phishing site that requested your private key/seed

[lionheart78]

Signing from your wallet with an address that belongs to you. Which wallet are you using?

If someone else is actually really using your wallet already, then you'd best ditch your wallet and sweep all your funds out.

Huh.. But we can both signing from my wallet...

*It's not a real situation! It's just a model!

Anyone who has the private key own the wallet.  So if it happens that someone got your private key, then that person also owns that wallet.  We can identify the true owner by the record that has the earliest record or file of wallet.dat or json file if it is in electrum.  If it is created online, you can check the history of each pc as long as the cookies or history of the browser is not deleted. If all is not available then we cannot prove the true owner of that wallet.

That at least what I think to verify the true owner of that wallet.

I also agree with buwaytress to forget about the wallet if ever that is already emptied out by the owner or the hacker and never use it again because it is already compromised.

[CryptSafe]

What if i catched some mot****er, who is using one of my wallets - how can i prove that it's mine? 

This question is a technical question and  sounds like someone trying to prove a case of ownership either in a law court to clarify an argument or maybe a police report. If you must claim a wallet belongs to you then the first thing you can prove with that is is presenting your seed phrase or secret keys but if in a case there are two holders of the secret keys trying to claim ownership then it will need some extra efforts to do so.  I believe there are some remarkable events attached to an occurrence for which the real owner of the wallet must remember to explain, some events can lead you to explaining the process and how it began. In a situation where by two people are dragging ownership of a thing, I believe from mere explanatory you could tell who the owner really is. Looking at this, as a wallet related, the owner must have had some experience to some of the token on his or her wallet with some memorable occurrence which can not be easily forgotten.

[Stalker22]

Let us make it maximum easy.

We both know seed-phrase. How can i prove that the wallet is mine???

Why bother proving that a wallet belongs to you? Even if you manage to prove it, what is the point? The other person will still own the private key, and that cannot be changed.

One possibility that comes to mind is being able to demonstrate the priority of using a particular address. For example, if you have made a public record of the address or have used it to deposit funds, and you can prove that the transaction belongs to you.

[dansus021]

Signing from your wallet with an address that belongs to you. Which wallet are you using?

If someone else is actually really using your wallet already, then you'd best ditch your wallet and sweep all your funds out.

This is simple yet the best solution in my opinion
but you have said that some people are using it  . I mean if you still have the access to that wallet it's better to move your money out than argue. and move on. before people who using it did it first

[Hispo]

I don't even know why anyone would ever share a seed-phrase with another person, it is never a good idea and can only bring problems in the future.
In my eyes, seed phrases are like toothbrushes, not supposed to be shared  

OP, as people have told you, if you have any funds in that "wallet", move them to a new one that only you control and move on. If you need to prove ownership of some address to claim some money, airdrop or whatever, it is unlikely there is a solution to this matter if you do not know the other person in real life.

[cr1776]

Signing from your wallet with an address that belongs to you. Which wallet are you using?

If someone else is actually really using your wallet already, then you'd best ditch your wallet and sweep all your funds out.

Huh.. But we can both signing from my wallet...

*It's not a real situation! It's just a model!

Pretty much the answer is: if you hold the keys, they are your coins.  So if you both have the keys, you better move the coins immediately to a wallet that you control.  And if a criminal has the keys, they probably will have already done that.

[JustAsk]

Your case and question don't portray sincerity and it's incomplete at the same time. Is the wallet custodial or noncustodial? Do you still have crypto assets in it?

Based on these, if you don't have crypto assets in it, why waste your time, go for another wallet for privacy and security reasons. But if you have crypto assets in it and it's custodial, contact your wallet company with your original details for a reclaim. However, if it's noncustodial, signing a known message with your private key will be the most viable way out.

Let us make it maximum easy.

We both know seed-phrase. How can i prove that the wallet is mine???

Here is the maximum easy answer. If you both have the seed phrase then the wallet is both of yours.

Explanation being that ownership of an address comes down to who knows the private key and I guess in legal situations who used the key… If you both have the private keys then you can both use them. I don’t think there’s been court cases yet where people dispute the ownership of an address and both have the keys. The only court cases I’m familiar with are the ones where someone is trying to claim ownership without having the keys.

So we can say that if I recall my seed-phrase that way - it is mine?