Why does my BTC address keep changing?

I've got just one hot wallet on my phone, the unstoppable wallet, and I mainly use it for online payments and to get my mining rewards from various pools. But I’m curious about why this wallet changes my Bitcoin address every time I use the current one to get some BTC. Also, does this switching actually help with privacy? I came across a comment saying that changing addresses could somehow reduce the risk posed by quantum computers. Honestly, this is kinda confusing to me. What's the link between this address change and quantum computers? I mean, even if those computers were real, they wouldn't just access your wallet through the address. Or am I missing something important here?

Using different address each time does help your privacy. If you want to know the "how" here is an article by Trezor: https://trezor.io/guides/trezor-suite/use-new-address-for-each-transaction Pretty much all wallets nowdays does this. It's mainly the exchange's that support only one receiving addresses. This has been a thing way before Quantum computers became a subject of discussion but if you're interested reading as to why not reusing addresses might help, see this article from project eleven: https://blog.projecteleven.com/posts/hd-wallets--quantum-risk-does-reusing-one-address-endanger-the-rest

This is for your own privacy. When you received payment from the first address on your list of "received" address, the next time you want to copy another one, it gives you a different one from the list of your generated address, this is to avoid address reuse to improve your privacy. The problem with unstoppable wallet is that you can't view list of your generated address unlike electrum, bluewallet or cake wallet that do give gap limit of 20 generated addresses for change and receive. I will suggest you switch to bluewallet or cake wallet for mobile wallets, electrum for android  or use electrum and sparrow for pc, import your seed phrase from unstoppable to any of them. When you use different wallet address to receive payment, it improves your privacy when you spend each separately. The catch for quantum computers is when you spend Bitcoin on address multiple times, it exposes your public key. This public key can be used to get your private keys which put your Bitcoin at risk. To prevent this from happening, anytime you want to receive Bitcoin, use an new address and when you want to spend it, spend it all at once so that if even if your public key is expose, you don't have to worry about it.

Now take it like this, the main problem with address reuse as regards quantum attack is just its public key vulnerability as it’s being exposed when reused. Look at it like this when someone send you bitcoin to your address, it is only the hash that is on chain, the actual Public key stay hidden. so when it is not reused it should not be exposed to quantum threats. That is why it is safe to say that Unspent UTXO are safe from quantum attack.

Each transaction changes your Bitcoin address to make sure that your money and history stay private and that no one will know your total balance or can track who has paid you, as though you are using new clean box each time. Having same address over and over lets hackers or businesses link all your trades and follow your money easily, however, changing them makes it very difficult to track your path. It also protects you against future quantum computers since even though your address is safely mixed up, your public key is briefly shown to network when you spend money, by using new address each time, you can make sure that key does not stay out in open where it can be grabbed by fast computer later. Although these super powerful computers are not yet here, it is smart idea to change your address to keep off nosy eyes today and technical risks in future.

FYI, your question already answered on their website. Quantum computer need public key (of Bitcoin address) to perform brute-force and get it's private key. The public key exposed when you create Bitcoin transaction that spend coin from address you chose. So what Unstoppable wallet does reduce the risk by splitting your Bitcoin into multiple address, where it's public key only exposed when you need to spend the coin.

It is for your privacy, and even without any possible threats now or bigger threats in the future from Quantum computers, you should use Change addresses for your privacy. What is the "Change" address on bitcoin wallet ? read to know ! General guidelines for sending BTC transactions.

Though it may not be all the wallet that supports changing wallet address its time you want to use such for a transaction, but it is important that we know the relevance of having a changed address for privacy sake just as many have already highlighted and we can check to know more details about how this is important from the links that have been supplied, only that some users are not privacy conscious and doesn't know the relevance to why this is important because they don't know what they protect and stand to lose when they don't use a wallet that don't supportsa change address.

Is changing address a serious issue for you? I don't think so; you still can use your old address if you want since it's always valid if the address was created from any non-custodial wallet. As their website stated (quoted above by another user), it's because of protecting user privacy, and it's true. When you use the same address everywhere, it means the sender would know and trace your funds. When you use a new address each time, the sender won't trace your other address unless you make transactions together from all the addresses. Regarding quantum thread, I am not sure if it does prevent when changing address. But likely it would reduce the risk, unless a quantum computer knows the public key, then it's hard to brute force. I have less knowledge about quantum power, but it's better at least that you protect your privacy by using a new address for each transaction.

@Cookdata is this also possible on hardware wallets? All the examples you dropped are all Bitcoin hot wallets, I have received Bitcoin on my hardware wallet several times but my address is same. Or this has something to do with my airgapped device? I am using keystone, or maybe it's something I can do manually? The only way to have a different address on my hardware wallet is changing the format, from Native segwit to others available. By the way users can view past addresses used on Unstoppable wallet now, maybe it was not available before I can't say, under the "receive BTC" address you will see a used addresses tab

Not when your spend coins from an address several times that the address is vulnerable, it is when you spend coins from the address. Even if it is just ones, the public key of the address is already known and can be used with quantum computers to know the private key. This is when quantum computers are capable of doing this, but no computer can do this for now.

This has been encouraged ever since. Yeah, it's about your privacy and not the avoidance of risks associated with quantum computers. It helps your privacy because having transactions that are isolated from each other would make it hard for other people to link them all to you. Also, it's hard for them to know how much funds you really have and your spending patterns. And in case one address is linked to your identity, there's not much information that's compromised.

The receive address generated is always there but not showdn, it depend on the software you are using. Most hardware wallet and some software do this for privacy to avoid address reuse. Refer back to ABCbit reply This has nothing to do with airgap or cold storage, you can link a Trezor wallet to electrum software and you will see the list of generated addresses there. I have the version 0.42, you can still view past transactions and addresses that received and sent when you check on the Bitcoin asset but there is no anywhere on the wallet to see pre-generated addresses. You can do this on bluewallet, check both receive and change address, if it's used or not, number of transactions.

Yeah that makes sense, it really depends on the wallet. Some just hide those addresses, while others like Electrum show them. And yeah, avoiding address reuse is important for privacy.

Changing your address after use can help protect your privacy, and I believe this is something that should be taken seriously because the first address used is already known to the other party, which could allow them to identify the assets associated with that address. Users who care about privacy often practice this in every transaction they make, as it is a privacy enhancement that is highly recommended. In other words, what that party is doing is a form of care.

Below is the quote of Satoshi when he was asked similar question about address reuse, it’s strictly for privacy sake. But this should be Know that for it to be privacy protect you must actually spend everything on that address and do not allow it to mix with the other addresses, this is why you see some users actually wary of consolidation of your UTXOs on different addresses to one address as it’s actually reduces privacy, This was said even before this recent quantum computer recent FUD thing.

Use different wallets, use different change addresses are common advice for privacy. Just in case, Satoshi Nakamoto also advised that wallets should never be deleted even you no longer use them.