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10

There are both security and privacy related issues that arise from address reuse. Based upon your question you are less concerned with the privacy implications and more concerned with the security implications in this question. I will discuss security first before briefly mentioning why the privacy implications are greater than the security implications. ...


8

There's a bigger attack surface for someone that wants to doxx you. They only need to link a single transaction to your real life person to know all the transactions you've participated in. A single payment to newegg, for instance, will identify you across all transactions. Very few transactions are completely anonymous. But yes, if they're all completely ...


7

The only reason why it is recommended to use a different address for every transaction, is for increased anonymity - it makes it more difficult to trace, and next to impossible to prove, that the recipient of transaction A is the same person as the recipient of transaction B. If you publish an address to receive payments online, and keep it static, everyone ...


6

Yes! With an HD (Hierarchical Deterministic) wallet you control all the addresses inside of it. Using a new address for each transaction is actually a good thing for privacy. https://en.bitcoin.it/wiki/Deterministic_wallet https://community.coinbase.com/t/why-did-my-address-change-did-i-lose-some-payments/1589/2 To answer your last question you don't need ...


6

Why address reuse is discouraged: Reduced security An unused address is protected by ECDSA AND several SHA-256 and RIPEMD-160 operations, but only ECDSA after being used because the public key must be revealed during spending. This has been shown to open up several possible attacks in the past.[1] Reduced privacy All participants who you give the address to ...


5

This is a weird question because you have to send from the address you receive from. If you receive all your bitcoin to the same address, you will inevitably be spending from that same address as well. When you receive to the same address, it ties together the addresses that are paying you. If you are running a business, this could allow chain analysis to ...


5

You need to differentiate between the website's wallet (Blockchain.info-wallet) and the blockchain itself. You are allowed (by the bitcoin protocol) to make as many transactions per adress as you want. But wallets try to make it as comfortable as possible for you and use one adress only one time so that you are acting as pseudonymously as possible. You ...


5

Bob can provide Alice with an extended public key (xpub). This will allow Alice to generate as many addresses as required, all of which will be accessible to Bob via the corresponding extended private key (xpriv), which only he has access to. There are many tools and libraries around that support address derivation from xpubs, such as BitcoinJS-lib. As far ...


5

Can somebody take the transaction tx0 I signed and publish it in order to spend the new coins with the old transaction? No. Firstly, the transaction inputs are already known to have been used. Any node examining the block will know that the rerun transaction has invalid inputs. Secondly I expect (but haven't checked) the inputs to the signature include ...


4

It is absolutely safe at the moment since ECDSA is considered safe. People rather don't like to reuse to preserve anonymity or make coins harder to steal. This is because addresses in Bitcoin are not published directly in terms of the public key, but a hash of it. This way nobody can link the hash to the corresponding public key as long as the contained ...


4

The gist of the reusable payment code BIP is that you can gain some measure of address privacy by combining BIP32 (hierarchical deterministic wallets) with Diffie-Hellman key exchange. To understand what this means, let's figure out what the current situation of bitcoin wallets is. Originally, in the reference client, bitcoin wallets simply generated random ...


4

The reason is privacy. If you reuse the same key for every transaction, everyone who ever transacts with you can infer your entire balance. No, public keys should not be identities, exactly because the transactions to them are public too. Your ability to create many pseudonyms in the system the only way through which it has any privacy. By reusing ...


4

You can receive as much as you want to an address, but you should spend from that address only once. The reason you want to spend from an address only once is that this exposes your ECDSA public key as part of the spending sigscript. Should a vulnerability for the secp256k1 curve be found, your funds would be in danger. This is somewhat unlikely, but it is ...


4

Likely the sender didn't have an unspent output that had exactly the amount he wanted to send. So he choose an unspent output that had enough and sent the remainder back to himself. Accounts do not automatically combine the funds they receive. They have a bundle of unspent transaction outputs which they can only use by completely consuming them. You might ...


4

Why is that so, don't you only need 1 private key to hold all bitcoins and manage them? Sure you could use only one private key and its associated address, but that is not recommended. It is more secure and more private to not reuse addresses. Instead you should use a new address for every transaction you receive and for every change output you make. Thus ...


4

Q1: Depens on how you use it. Transactions to an address does not decrease it's security. Using a cold-storage wallet and taking it online exposes your wallet and it's security. Q2: It's correct. Most exchanges require KYC(know your customer), they store information about you and your withdrawal addresses. It's possible to create a new address for each ...


4

Transactions explicitly refer to which UTXOs they are spending. You can construct a transaction which only spends one of the two 5-BTC UTXOs, and sends 2 BTC to the destination and 3 BTC to a (possibly new) address of yourself. You can also construct a transaction which spends both, and sends 8 BTC back to yourself. Or it could have multiple outputs that ...


4

I think it would be helpful for you to identify your service here, so that I can encourage people to not do business with you. Users generally have no idea if this will work safely or not, so a notice will not be sufficient. If you send users funds to addresses they did not supply you should be prepared to pay them out when they report the funds have gone ...


3

You can certainly give out the same address to as many people as you want. An address is really just a representation of the public part of a cryptographic key pair, and you will still have the corresponding private key. That means, the address will still function, regardless of how many times you use it to receive money. However, as the app tells you, ...


3

The bitcoin addresses are permanent addresses. You can re-use the addresses if you want. But when reusing it causes privacy issue as any one will be able to find out the number of transactions or the total balance that address has. (you found out that there are 641 transactions in that address). To avoid this, its better not to reuse address and use ...


3

The simple explanation is that the attacks that quantum computing enables require information (the public key) that isn't available until after the first transaction is seen. Until the first transaction spending an output, all that is known is the hashed version of the recipient key (aka the address) which isn't enough to mount the attack. If fully ...


3

For a blog that only receives occasional small amounts you probably shouldn't worry too much about it. However, if you plan to scale up, here are some things to consider: One issue with using the same address for all transactions is that people can see the total amount received by that address and know how many bitcoins you have. If the total is large ...


2

Reusing an address is a security issue if you have a weak random number generator, as was an issue with the Android Bitcoin Wallet. I should note this was android's fault for using a bad generator and was fixed quickly by the app developer, though some people lost coins because they had signed multiple messages (i.e. transactions) with the same address and ...


2

The more transactions tied to a particular address, the less the privacy. Hence a need for individuals to use Hierarchical Deterministic (HD) Wallets that generate a different address for receiving each transaction.. Look at difficulty factor and note 14TYdpodQQDKVgvUUcpaMzjJwhQ4KYsipa. Then look at 14TYdpodQQDKVgvUUcpaMzjJwhQ4KYsipa. With the example, it ...


2

It is not clear what exactly happened. If you've made two subsequent transactions to the same address that should not be a problem. Addresses can be used more than once to receive money. If you created two transactions that spend the same transaction outputs, there is no problem, because only one of them can confirm. If your transaction simply didn't get ...


2

Once your import the key, the key now exists in two places: your paper and your wallet. Because of this, you've lost the advantage that a paper wallet has for cold storage. What you now have is a paper backup of one of the keys stored in your hot wallet. Any risks of a hot wallet now also apply to your paper wallet. In addition, there is the inherent ...


2

No it will not decrease the security of this wallet. Security concerns happen when you have to use your private key (i.e when you spend money). Reusing an address will indeed allow other people to have more information about the amount of bitcoin under the control of the same person. Furthermore, someone having access to a large set of payment data (i.e ...


2

that's not a bad idea in regards of doing business and distributing it to people. however, as far as I know, a single address is fine because the address itself is secured. the security flaw of a single address distributed will be - people can check the addresses on how good your business is doing. hehe. correct me if I'm wrong. Wishing you all the luck with ...


2

With option 2, most analyses will conclude that Alice owned A1, A2 and A3, because the transactions which spent them have no change address. Typically, you assume that the amount you have held in a TXO never exactly matches the amount you're making as a payment, so transactions usually have change outputs too. I think you have a little misunderstanding ...


1

Alice gets her computer hacked by Mallory, and she steals her wallet. Fortunately, Alice had encrypted it with a strong passphrase. Alice wants to sue Mallory for breaking into her computer, so she gets a lawyer, Bob. Alice's address, 10BTC --> Bob's address Unfortunately for Alice, Mallory controls a node on the Bitcoin network, not too far from Alice, ...


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