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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.

5
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2answers
159 views

Can a full node provide a bogus block bloomfilter to a Neutrino node?

When a thin client using BIP157/BIP158 (Neutrino) requests the block filter for the latest block, would it be possible for the full node serving this request to attack the Neutrino node by providing a ...
0
votes
1answer
27 views

LND Security best practices? Disaster recovery?

Can anyone share a knowledge how to _ secure LND node _ backup node with all Channels I think only a seed will not be sufficient. What is your plan B in case of disaster? How to do an Emergency ...
0
votes
2answers
32 views

How could a lightweight wallet determine the validity of 0-conf transaction?

I found that a lot of people are interested about security of 0-confirmation payments. But, it seems that most discussions focused on double-spending (like broadcasting two or more conflicting-but-...
12
votes
1answer
1k views

What is the origin of insecure 64-bit nonces in signatures in the Bitcoin chain?

In Biased Nonce Sense: Lattice Attacks against Weak ECDSA Signatures in Cryptocurrencies Joachim Breitner and Nadia Heninger use a lattice based algorithm to recover private keys from signatures in ...
3
votes
2answers
1k views

I think my bitcoin wallet was hacked. What to do?

I opened bitcoin-qt after not mining for a couple months and found that I suddenly have no more bitcoins! And I see that there were 2 transactions that I did not authorize sending my coins to other ...
1
vote
1answer
40 views

Security of Bitcoin Wallet

I have a doubt on Bitcoin wallet. Suppose I have an online Bitcoin wallet. Now, someone breaks into my computer and steals my Bitcoin wallet. Fortunately I have a backup of my wallet on another ...
3
votes
2answers
350 views

What is it about a Trezor that means it can't be infected by malware?

The Trezor testimonials include that TREZOR ... cannot be infected by malware What is it about a Trezor that means it cannot be infected?
4
votes
1answer
145 views

Lightning Network: asymmetry in the information tracked by each participant?

In following paper, written by Christian Decker et al., there is a paragraph that is not clear to me. eltoo: A Simple Layer2 Protocol for Bitcoin "The central idea of Lightning is to invalidate ...
1
vote
1answer
42 views

Security implications of removing CHECKSIG in a test

If I conduct an htlc transaction on testnet that does not include OP_CHECKSIG will it still cost an attacker more than (say) $10 in processing power or storage to subvert my tests? Details: I'm ...
2
votes
1answer
102 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 ...
1
vote
1answer
168 views

Who decides what the next, correct Nonce is?

As I understand finding the correct Nonce is the basis when hashing transactions for Proof of Work. How and where is this decided in the ecosystem what the next Nonce is? In my limited understanding ...
1
vote
2answers
107 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
votes
1answer
2k 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
votes
1answer
31 views

How Spectre tolerates spam transactions?

Spectre is a DAG based (directed acyclic graph) distributed ledger (a structure as an alternative to blockchain based distributed ledger). Is there any mechanism in Spectre to prevent sending spam ...
0
votes
2answers
24 views

Physical bitcoin vs. Paper wallet?

What is the main difference between a Physical bitcoin and Paper wallet ? And which one is more secure ? And why ?
1
vote
2answers
206 views

What are the drawbacks of using a web based wallet and how to overcome that?

Can anyone tell me why many prefer to use application when compared to web based wallets. What are the drawbacks of using a web based wallet and how to overcome that?
3
votes
4answers
334 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 ...
5
votes
1answer
1k views

Why is increasing block size in the Bitcoin network considered to decrease security?

I have been doing some research on the Bitcoin Cash hard fork and the main contention of increasing the block size appears to be the possibility of less security on the network. How does an increased ...
0
votes
1answer
58 views

Why are the inputs of Bitcoin transactions signed?

This is my understanding of what a transaction looks like: inputs: input0: txid: <funding tx0 TXID> outputID: <output ID of UTXO in the funding tx0> scriptSig: <...
0
votes
2answers
45 views

What Happened 12/30/17 Last Recieved Transaction into Bitcoin Core Wallet

I have found a different receiving address within my wallet that is not mine... at least I did not create it. It seems to me that all of my transactions are now going to this new address instead of ...
0
votes
1answer
39 views

How does using a Turing-complete programming language compromise the security of the network? [duplicate]

I have read many places that the decision for Ethereum to use a Turing-complete programming language sparked a lot of concerns over security. From my understanding, not using a Turing-complete ...
1
vote
2answers
860 views

Is it possible to bruteforce the seed?

Is it true that the "seed words" bruteforce more reliable for to get profit than searching of a "random number" for to open some profitable outputs? The last one is impossible due to math, but the ...
1
vote
1answer
46 views

Bitcoin Mixing? Is it even real?

I have been trying to find a "bitcoin mixing" service but it seems that ALL the "bitcoin mixing" sites I have looked at are scam. Does anybody know of any that are actually real and do what they say ...
1
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2answers
53 views

Exact definition of “Liveness” and “Safety” properties in a consensus?

Two main properties of a consensus are "Liveness" and "Safety". What are the exact and precised definition of "Liveness" and "Safety" properties in a consensus ? Are the following definitions ...
1
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0answers
37 views

Why Spectre has a “weak” liveness?

According to this article: (https://medium.com/@avivzohar/the-spectre-protocol-7dbbebb707b5) written by one of Spectre's author (Aviv Zohar), it is mentioned that Spectre has weak liveness. What is ...
11
votes
1answer
207 views

Schnorr's batch validation

In the recent BIP about Schnorr's standardization, Pieter Wuille presents an algorithm for batch validation. In my understanding the most heavy operation is the multiplication by a scalar: to make ...
2
votes
0answers
43 views

Sybil attack with IOTA?

IOTA is one of the DLTs uses DAG (Directed Acyclic Graph) as data structure. The solutions to attacks proposed by IOTA white paper seems unconvincing, in particular, in case of double-spending, it ...
3
votes
2answers
1k views

Make remote RPC connection to bitcoind server secure

I set up a bitcoind server on an Ubuntu server and I can remotely execute commands on the server. I am doing this with Java/RPC. To execute a command I need to provide a username and password. But I ...
6
votes
2answers
612 views

What alternatives are there to hardcoding checkpoints into the Bitcoin client?

Checkpoints seem like a crucial part of the security & validation apparatus in Bitcoin. Is there a written policy in place, among the developers defining the maximum interval between checkpoints? ...
33
votes
3answers
7k views

What are checkpoints?

I often read that checkpoints protect the network from a 51% attack because an attacker cannot reverse transactions made before the last checkpoint. How exactly does this checkpoint mechanism work? ...
6
votes
2answers
1k views

Can you mine without transactions?

As far as I know, mining means verifying transactions and thus keeping the Bitcoin network alive. Today, at a local meetup, some people have informed me that mining doesn't need transactions. They ...
4
votes
1answer
358 views

Why was an insecure merkle tree implementation chosen?

At risk of creating a "lets discuss politics" question, let me clarify that what I want to know is whether there is a known benefit to Satoshi's "duplicate the last hash" merkle tree implementation ...
0
votes
0answers
45 views

Byzantine Fault Tolerance Threshold of Bitcoin: 1/2 or 1/3?

According to this answer: https://bitcoin.stackexchange.com/a/58908/41513 a Byzantine Fault Tolerant (BFT) consensus threshold is 1/3, that is contrary to belief that the Bitcoin network is secure (...
0
votes
1answer
27 views

Does Electrum store my seed in their server?

I am new to Bitcoin. I used Electrum software to create my first wallet. When the software generated 12 words, I had written down that in paper. These word are very important, right? But the software ...
1
vote
1answer
48 views

Is the statement that LN hot wallets will be less secure than non LN hot wallets correct?

I say this because of the following reasoning: Lightning network wallets will have to completely possess my private key, whereas non-LN hot wallets will most of the time only have my key encrypted (I ...
5
votes
3answers
3k views

How to generate a public key from a private key using Elliptic Curve Digital Signature Algorithm

I'm trying to understand the graphical basis that underlies the discreet logarithmic Elliptic Curve Digital Signature Algorithm (ECDSA) introduced in Chapter 4 of "Mastering Bitcoin" by Andreas ...
0
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2answers
26 views

Hiding identity in digital currency era

I have a question about the security of digital currencies, however still I have find a clear answer for that. No matter what is the currency, e.g bitcoin, monero, ..., at the end of the day, I have ...
8
votes
1answer
1k views

What is BlitCoin?

I saw BlitCoin mentioned on this forum thread, but didn't understand what it was. Can someone explain what does it do?
129
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8answers
46k views

What can an attacker with 51% of hash power do?

Suppose organization X has 51% of the hash power for a period of 1 week. In this week, what exactly can and can't X do?
0
votes
1answer
70 views

Why can a wallet not compute the private-key from a public-key?

my goal of questions this is why any wallet not able to compute private key created with public key generate?
1
vote
1answer
26 views

What would happen if I publish a modified version of an earlier block? Would it be rejected immediately by peer nodes?

I am reading the book "Mastering Bitcoin" and have finished reading Chapter 2 and 10, but I still don't find the answer. Suppose the current main chain has 5 blocks: B0 <- B1 <- B2 <- B3 &...
4
votes
1answer
658 views

What happened to my coins, hacked?

I'm new to bitcoin, downloaded the bitcoin.org client, encrypted my wallet, and purchase a few bitcoins (5.25), for learning purposes. But now my coins seem to have disappeared to an unknown address. ...
1
vote
1answer
46 views

Have there been any examples of people manipulating transactions in a way that waiting for more than 1 confirmation would avoid?

A lot of bitcoin exchanges require some minimum amount of confirmations before they consider money deposited. Is there any evidence that this actually does anything? Has someone ever before ...
0
votes
2answers
219 views

Address reuse, one address per person

I know about the privacy and security implications of address reuse. But I was thinking about a scenario where I have one address for every person I receive transactions from. This would still have ...
1
vote
2answers
43 views

Can't understand specific problem of Bitcoin anonymity

There is an problem shown in bitcoinwiki: Someone runs both a money exchanger and a site meant to trap people. When Mr. Doe buys from the exchanger and uses those same coins to buy something ...
2
votes
1answer
61 views

Can I, and should I, verify bitcoin core source code before compiling it?

If I use bitcoin core binary release I can verify them with the gpg keys of the core developers. Is there a similar process for the source code? A follow-up question: Is it preferable to use signed ...
2
votes
2answers
99 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 ...
1
vote
1answer
25 views

Review sites for the hardware wallets? [closed]

As I understand it there are four (4) hardware wallets produced currently (2018). Which businesses, web sites, or academic papers in the field review and compare the security of these devices? Is ...
3
votes
1answer
104 views

A couple of questions on Schnorr sig

In the BIP by Pieter Wuille it is told that the key prefixed version of Schnorr signature is needed when the scheme is used in combination with BIP32's unhardened derivation. Could someone provide an ...
5
votes
3answers
277 views

Bitcoin value vs. Supercomputing

What protects the stability of Bitcoin's value if supercomputers or some other technological breakthrough allows them to be mined at rates we have not anticipated?