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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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1answer
54 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 ...
5
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1answer
83 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
66 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
50 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
17 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
35 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 ...
1
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3answers
256 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 ...
2
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1answer
28 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
706 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
41 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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2answers
6k views

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

What is the algorithm used for encrypting the wallet.dat file?
-4
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1answer
881 views

Could miners possibly steal SegWit transactions on The Real Bitcoin? [closed]

Going to be lolz epic when all the SegWit transactions are double-spent, i.e. stolen by miners on The Real Bitcoin (the legacy Satoshi blockchain). Can anyone offer any refutation, confirmation, or ...
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2answers
47 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, ...
0
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1answer
108 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?
10
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2answers
7k views

The length of the Bitcoin's private keys

I read here: In Bitcoin, a private key is usually a 256-bit number ... Although it is a silly question, is this length safe? Based on this site, Elliptic Curve 256 bit keys are safe until 2040. ...
4
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2answers
303 views

Can bitcoin node startup be secure without validating the entire blockchain?

One of the largest hurdles in my mind to increasing the number of full nodes operating is the startup cost related to downloading the blockchain. A similar but less important (in my mind) issue is ...
32
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1answer
51k views

How can I restore my wallet?

I just purchased a new laptop and I want to decommission my old one. I have a back-up of my wallet.dat file copied to my new PC. What do I need to do to restore it to my Bitcoin (Windows) client? ...
0
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1answer
31 views

Beneficial proofs of work [duplicate]

I'm new to this community and a Bitcoin novice. I believe to have understood the concept and purpose of proof of work but also, that the high energy consumption of proofs of work is a major problem ...
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6answers
7k views

51% attack - apparently very easy? refering to CZ's “rollback btc chain” - How to make sure such corruptible scenario can never happen so easily?

I was shocked to see binance CZ comment to literally "roll back" the bitcoin chain by just "calling" in some favors from "friendly" Asian miners . This ONE person could effectively do it??? I mean ...
0
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0answers
32 views

BIP32 HD Wallet vs HMAC vs Hashing

I've been working on a website which will be caring out various cryptographic operations. On the website users can post Ads. Each Ad has a monotonically increasing unique ID. For each Ad, I would like ...
2
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1answer
50 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 ...
2
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1answer
136 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 ...
2
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1answer
45 views

Why doesn't the Bitcoin-qt client ask for the Wallet passphrase upon startup?

I've just encrypted my wallet.dat file using the "Settings -> Encrypt Wallet" menu option. I then closed the client and re-opened it. I was expecting to be prompted to put in the wallet password ...
1
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2answers
22 views

Organization to keep track of wrongfully obtained bitcoins

I am curious whether there are any organizations that are actively trying to monitor bitcoins from illegal sources. I understand that 'when done properly' you can make bitcoins practically ...
1
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2answers
127 views

Does my Electrum wallet become less secure if I keep generating seeds until I see one I like the look of?

Let's say I want to create a new electrum seed... I didn't like the initial seed words, since I want to remember them and these didn't look too appealing. Looking "too random" for my taste. When I ...
0
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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 ...
0
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2answers
103 views

Is it more dangerous when 51% attack happens than just having a pool with >50% hashrate?

Many people told me that, if a mining pool performs a 51% attack, the price of the coin will drop. But I disagree. There are pools with >50% hash power already for a long time. Flypool is an example....
3
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4answers
354 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 ...
1
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1answer
47 views

Prove that xpub matches xprv?

I'm researching a paper wallet system where I generate an HD xpub/xprv using an offline laptop. I write down the xprv by hand. I capture the xpub via QR code using my phone, to transfer to an online ...
0
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0answers
29 views

Wallet recovery from seed phrase [duplicate]

How does a wallet become recovered based on a seed phrase? From what I understand, the seed phrase is another way of representing the private/public keys. Since address reuse is frowned upon, and we ...
1
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1answer
810 views

Is the following a valid bitcoin private key? - FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE

In secp256k1 (Bitcoin's elliptic curve) it is defined that valid private keys may range from 1 to FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE BAAEDCE6 AF48A03B BFD25E8C D0364141 - 1. (https://crypto....
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2answers
2k views

Why DARPA wants blockchain based secure messaging system

DARPA (US Defense Advanced Research Projects Agency) has released a Request for Proposal for a Secure Messaging Platform using a blockchain framework. The following is the Objective paragraph from ...
2
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2answers
510 views

getnewaddress (RPC) on encrypted bitcoin wallet without wallet password?

Say for example an encrypted wallet has 5000 addresses already pre-generated in the keypool. Can getnewaddress be called via RPC command without knowing the actual wallet password? I envisage a ...
3
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1answer
85 views

What are the potential security issues when running a Lightning Node on my home network?

If I was to run a lightning node on my home network (and for example, not running the node through TOR), what should I worry about? Furthermore, what OS, settings and software should I use to ...
0
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1answer
218 views

Someone is using a bitcoin account to blackmail me [closed]

Someone using a bitcoin account is trying to blackmail me. The account number is 1Mtsd3wXgkJnApaNpqaSSWLC6gCLBBxuaGG. I still have the email they sent me. I can also provide that email if needed, or I ...
3
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2answers
300 views

To what extent does asymmetric cryptography secure bitcoin transactions?

Is there a specific attack or bug which asymmetric cryptography prevents during bitcoin transactions?
1
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1answer
36 views

What makes Bitcoin transaction secure against attackers/hackers?

Wanted to know what is it that makes bitcoin transaction secure and make it less vulnerable to attackers and hackers
0
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1answer
53 views

Possibility of a DDoS attack

Theoretically. This is not a mechanism of any kind of attack, but It's about the "lost" coins. May be. It is just for an educational experiment. What if someone has the ability to send transactions ...
2
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3answers
729 views

What can you do with the private key?

I am trying to understand all security regarding blockchain and bitcoins. Let's say you have a bitcoin wallet which is secured, only you know the private key. This bitcoin address was created on one ...
32
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2answers
13k views

What is a Finney attack?

What is a Finney attack? Extra points for explaining its purpose, the prerequisites for it to be possible, how the attack can be performed and the origin of the name "Finney attack".
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2answers
37 views

How do I find out where a bitcoin address is from?

I am not looking necessarily a name but more like is it an offline, coinbase, blockchain.com, etc... I had $80 sent from my account yesterday and it says it went to ...
2
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1answer
53 views

Does assumevalid lower the security of Bitcoin?

Bitcoin's assumption was to download the blocks and verify it in order to prevent getting fooled. But by default, the assumevalid option is enabled in the software, which, as I understand it, makes ...
2
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1answer
52 views

Is this a collision attack or a 2nd-preimage attack?

This question revolves around Bitcoin Optech newsletter #51 (1) and an email thread from the bitcoin-dev mailing list (2). I asked the same question in a reply-email of the newsletter and the response ...
10
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2answers
2k views

Long term BTC investing

my question is, what is the safest way of buying and holding bitcoin for the long term? And I mean 10-20 years, either a lump sum or through dollar cost averaging, is a paper wallet the answer? Or ...
5
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2answers
614 views

Capturing IP address of transactions submitted to Bitcoin

Dan Kaminsky has pointed out that it would be possible to build a service that tries to infer the source IP address of each Bitcoin transaction. His idea, which he calls Blitcoin, works by ...
3
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2answers
152 views

Is possible to destroy the Bitcoin for just $500K? (51% attack)

Everytime I read about the 51% attack the answer was something like: is really expensive to get 51% of power on BTC and nobody will invest so much so to destroy the bitcoin. But I found this site ...
3
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1answer
44 views

How many nodes is too many?

Has anyone done the math on this? For example, if we had 10’s of millions of nodes all connecting to 8 peers would there be some latency issues in propagating blocks across the network in the 10 ...
1
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1answer
264 views

What bad things could happens if Bitcoind RPC is public?

It is always suggested to enforce authentication on Bitcoind RPC. However, in case the RPC authentication get compromised (or if it is public), what kind of bad things could happens? First I could ...
14
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2answers
3k views

How do you derive the private key from two signatures that share the same k value?

I wrote my own ECDSA signature algorithm just for the purpose of creating unit tests. With it I created two signatures which went into transaction 56ec7ca7df..., sending from 1GXFXm3es.... These ...
10
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1answer
2k views

Bitcoin automatically diverted to bech32 address

I sent bitcoin to an address starting 3Cn using Electrum but the blockchain viewers seem to show that it has gone to an address beginning bc1 as shown in the link below. Transaction Viewer How can ...