Questions tagged [security]

This tag should be used for questions regarding security issues with the design or implementation of Bitcoin and related cryptocurrencies.

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301 views

Why don't the miners just take profit from our coins and make the coin worthless?

You own a very valuable thing and you want to go to holiday without it, but there is nobody who you trust and who can look after the thing. So you take somebody unknown to guard it. You pay him a fee ...
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1answer
36 views

Relationship of Bitcoin address and Public Key

I am trying to understand relationship between your Public Key and bitcoin address. After reading few blogs my understanding was that after generating your Master Key pair, in HD wallet. One should ...
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45 views

Question to Marco Falke and to other Bitcoin Core developpers and/or reviewers [closed]

Dear Bitcoin community members, I will explained briefly the reason why I am writing here. I am working as a PhD student on the functioning of cryptocurrency governance. I'm trying to document two ...
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1answer
57 views

Is it possible to separate blockchain and wallet functions?

I'm looking for a way to use bitcoin-core in monero-way (It uses separate blockchain daemon and wallet daemon). I'd like to run bitcoin-qt interface on my laptop and connect to external node with ...
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2answers
43 views

What prevents a knowledgeable person from modifying their bitcoin data?

The average person would not have the knowledge, but what is the mechanism that stops a programmer capable of writing a wallet, from modifying the local bitcoin file/data to be, for example, 10 ...
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0answers
33 views

similar seed words minor sequence difference

I created a wallet weeks back and seemingly restored the seed onto my other 2 devices. Recently I got to notice that I had mistakenly logged into another wallet with identical seed words but I ...
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4answers
485 views

Is it wrong to spend Bitcoin from someone else's wallet if my Bitcoin client generates the same address?

I know this scenario is extremely unlikely but what-if by chance I get the same Bitcoin address as another user and the user has hundreds or thousands of Bitcoins in his wallet, is it morally/legally ...
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1answer
45 views

How do i differentiate between a scam and a real bitcoin miner?

Someone offered to trade for me through bitcoin. He said i should send a bitcoin to crytomine company then he is going to claim it from the company so that he trades it with a commission of 10% of ...
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3answers
145 views

Is it safe to create a Bitcoin account for another party? Is this a scam?

A guy I have been talking to says he is having trouble accessing his account and asked me to make a wallet in blockchain and then wants my login, password, and wallet id so he can use it in another ...
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3answers
283 views

How can Bitcoin be stolen?

If each bitcoin has a ledger (Peer to Peer) and contains all the transaction history since it was mined, then how come it can be stolen? For example, Bitcoins were stolen by hackers from Mt. Gox. If ...
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4answers
90 views

How the blockchain knows that its been tampered with?

I know that the transactions stay in the block and hashed alongside few other things and that hash is stored in the next block. And I understand that if you try to tamper with one of the transactions, ...
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3answers
2k views

If someone knows my bitcoin address, does this mean they can spend it or move it?

What if I wrote down or saved a file with the address on and someone found it, can they take my coins? How secure is it?
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481 views

I just lost 1.36275883 ($313), and I don't know how it happened or how to prevent it again

I just opened my multi bit wallet, and the 1.36275883 that was in there is now gone. It loaded a brand new wallet, so I don't even have my old wallet with the old transactions or password. I know ...
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1k views

What happens if my wallet gets “hacked” and my BTC is stolen?

What if my wallet gets hacked and the hacker transfers all BTC to his account? Is there is any way to get it back, or to open a dispute to specific address or anything else?
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1answer
29 views

Is it possible to brute force the Secure Element of Ledger Nano S?

Only things I could find about this subject always tell that Ledger has a secure element like SIM cards and credit cards have. Also something about another OS running near the main application. But ...
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2answers
180 views

Can signature be re-used to cash out everything in the address?

I Know for the P2PK locking script it was like this [pubkey] <OP_CHECKSIG> and then an unlocking script is provided as simple as this: [sig] But if it works like this, others can simply grab ...
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1answer
144 views

Lightning network hub security?

Reading the whitepaper, I came across a point: nodes wishing to act as effective intermediaries, 'hubs' or not, need high availability and need to operate autonomously. This means they must have ...
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1answer
34 views

How to add a second user with SSH access to my Ubuntu PC running Bitcoin Core?

I have a friend who is interested in learning Bitcoin CLI, and I told him I would look into giving him access to my node - in a non-destructive way - perhaps testnet only ? Totally trust this person, ...
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2answers
207 views

How can multifactor authentication be used when there needs to be two people with access?

For a business account at a Bitcoin exchange, either of two people need to be able to send bitcoins or withdraw. This account will be configured with two-factor authentication. How can two of the ...
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1answer
3k views

Private key to mnemonic words, is it safe?

Is it safe to do the following? Suppose I do not want the HD wallet, but I do want the convenience of using mnemonic words to remember the private key. I know I can convert the private key's hex ...
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2answers
34 views

What are some potential scenarios that a state actor can harm bitcoin if they control more than 51% of the hashing power?

As reported recently, China controls more than 51% of the hashing power and just in one province in China controls 54%. Assuming China has bad intentions and forces all these mining operators to ...
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3answers
548 views

Can nLockTime TX be used to flood Mempools?

What would happen, if I would create a large number of large transactions with a very high nLockTime? Would something stop me from filling not only the miners', but also regular nodes' mempools? ...
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1answer
54 views

Why is a 20 byte hash acceptable in p2wpkh but p2wsh needs 32 bytes?

Why is it acceptable to use a 20 byte hash to represent single-sig witness programs whereas a 32 byte hash is used for pay to witness script hash?
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1answer
766 views

Is JavaScript wallet generator available at bitaddress.org relatively secure?

I wonder if it's safe to use JavaScript generator available at bitaddress.org. Even if I'll generate it offline, how can I know if the algorithm is not using any pre-computed / pre-planned way of ...
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4answers
360 views

Store Bitcoins offline

I have some bitcoins and ether at Blockchain.info and I am really scared of losing them. How do I best secure them? Right now I have a paper with the code to restore my wallet, but my coins are still ...
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1answer
170 views

Does a HD Wallet log my IP when i do a transaction?

Companies like BitPay and Electrum, can log my IP when I make a transaction, right? If so, should I use a Web Wallet (plus VPN) for transactions?
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310 views

Are DAG-based crypto currencies as secure as proof-of-work based blockchains?

A key feature of blockchain based cryptocurrencies is that they provide inherently secure systems that don't rely on third parties. The newer DAG-based cryptos like Byteball are being touted as ...
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10answers
9k views

How can I keep my wallet secure?

The standard Bitcoin client does not encrypt wallet files, so any malicious user that gains access to this file will be able to transfer all the coins to their own wallet. Furthermore, if I lose the ...
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1answer
158 views

How do I securely update Bitcoin Core?

I am currently running a Bitcoin Core wallet 0.18.1. What do I need to do to update it to 0.19.0.1 version? Would be very grateful for instructions as I am relatively new to this.
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40 views

Bitcoin wallets- question about control and centralization

Community, Just a quick simple question very important for me to understand about the security of wallet types. Are there bitcoin wallets which can shut down and block/freeze/control your bitcoin ...
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2answers
98 views

Why is no security lost by using 32-byte public keys in Schnorr signatures instead of 33?

There is currently a discussion on the mailing list about truncating the 33rd byte from public keys when used in bip-schnorr. Public keys are (x, y) coordinates and compressed public keys simply ...
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1answer
51 views

Why one miner can dig out many blocks continually in one moment?

I am new to bitcoin and blockchain, I browed the website just now. There is a question confusing me, I find that one miner dig out blocks many times even in one hour. For example, this miner dig out ...
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51 views

Trading crypto currencies with dollars

After I have bought a crypto currency at an exchange like Binance can I sell for dollars if it is going down. Basically if I have a profit from a currency what can I do with it to protect it?
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38 views

How could PSBT deal with data capacity limit of QR code?

QR code has very limited data capacity. (According to Wikipedia) one single QR code can only carry <3KB of binary data. It's not rare for a PSBT to hit this 3KB limit, especially for ones which ...
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1answer
209 views

Can i trace a hacker by collecting data from Bitcoin api?

In Japan, MtGox, the biggest bitcoin exchange went down and went bankrupt due to hackers. So I'm working on a project in my College to enhance security of bitcoin transactions using the data mining ...
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2answers
84 views

Is the 51% attack the only technical reason no country will adopt Bitcoin as a state currency?

Is the 51% attack the only technical reason no country will adopt Bitcoin as a state currency? Lets suppose a country with GDP size less than 300 Billion USD adopt the Bitcoin as an official currency. ...
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3answers
5k views

Can one safely buy vanity addresses from a third party without risking one's coins from being stolen?

One can easily generate vanity addresses for Bitcoin, but they can take quite awhile to generate. Outsourcing that process to someone with a strong mining rig is an option, but then one runs into the ...
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1answer
48 views

Address Reuse issue

I dont understand how security works with multiple address using. I am trying to guess how security works here but need some feedback, so here are a few questions, and my own guesses. If I have total ...
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1answer
31 views

Race attack with transaction fees

let's say I run a simple race attack (say in a restaurant). I transfer BTC to the restaurant but seconds before (or after) I send the very same coins to myself. To make this deal more likely for ...
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2answers
222 views

How can someone lose funds in Lightning Network?

In Bitcoin once you own a private key associated with an address that had bitcoins on it, your funds are theoretically safe for ever. But on the Lightning Network, I see that once you send bitcoin to ...
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1answer
56 views

Why can't a longer key combat quantum computers?

Google's new quantum computer performed a calculation in 3.5 minutes that would have taken 10,000 years on a normal computer (so they claim: https://www.space.com/quantum-computer-milestone-supremacy....
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1answer
113 views

How can I protect my funds in the event a quantum computer breaks the ECDLP that Bitcoin relies on?

An interesting question was posted recently, discussing the idea of hashed addresses being (not meaningfully) quantum resistant. As Andrew's answer on that question points out, paying to a hashed ...
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2answers
107 views

Can a blockchain's transactions be reversed?

Blockchains are often described as 'immutable' (meaning the history cannot be rewritten after the fact), but is this really true? How easy is it to change the history? I have read about the Etheruem ...
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1answer
66 views

Whose to stop the coinbase devs from just draining all accounts and running of with the money?

I have been wondering, what would happen if the coinbase developers agree to drain all the funds of all their accounts and run off into hiding? Its not like anybody will be able stop them or return ...
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1answer
53 views

Can two bitcoin transactions from a Segwit address (p2sh-p2wpkh) have a reused R value?

Good day. I'd found these two transactions: https://www.blockchain.com/es/btc/tx/2b08d658045724aba40b58690ad84ec2af1f01ab58df37387dadd2b27789f44c and https://www.blockchain.com/es/btc/tx/...
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1answer
43 views

Security of ChaChaPoly (IETF rfc7539) in the noise protocol framework of the Lightning Network

According to this paper ChaChaPoly is secure against chosen known plaintext attacks. I wonder however if that security assumption is weakened by a lot since messages sent on the transport layer of the ...
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1answer
39 views

Could a malicious attacker subvert the Bitcoin network by failing to create a block?

I know its astronomically improbable, but say a malicious node "wins" the proof of work inherent to the Bitcoin protocol. If a malicious node simply waited indefinitely, or maliciously disconnected ...
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2answers
729 views

How will Lightning Network nodes secure their hot wallets?

The success of the Lightning Network is dependent on payment routing. Successful payment routing will require online nodes with automated signing facilities. This entails online nodes with hot wallets....
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2answers
6k views

How does the Bitcoin client encrypt the wallet.dat file?

What is the algorithm used for encrypting the wallet.dat file?

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