Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [security]

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

6
votes
2answers
602 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? ...
32
votes
3answers
6k 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? ...
0
votes
0answers
24 views

Collect bounty on security issue [on hold]

What is the Process for collecting a bounty on bug report security issue...i have proof of the file of mine taken and username (Is the username and a file transfer confirmation enough)
3
votes
4answers
321 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 ...
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 ...
3
votes
1answer
336 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
16 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
21 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
39 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 ...
6
votes
1answer
75 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 ...
0
votes
2answers
24 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 ...
0
votes
2answers
40 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 ...
-1
votes
0answers
21 views

secure open source Payment Gateway

I'm working on an open source multi coin payment gateway. BTC, BCH, ETH and EOS will be supported. My plan so far: The nodejs API runs on DigitalOcean. You send a GET request with your preferred ...
2
votes
1answer
84 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
2answers
100 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 ...
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?
128
votes
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
1k 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
59 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
22 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
654 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
45 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
208 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
38 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
47 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 ...
-1
votes
0answers
8 views

Bitcoin security in a transaction [duplicate]

Since there is no need for a trusted agency, how does Bitcoin ensure that no one can change a Bitcoin transaction?
2
votes
2answers
68 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
24 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 ...
2
votes
1answer
77 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
274 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?
5
votes
1answer
681 views

What precautions should be taken to protect a Ripple wallet?

What if a Ripple wallet gets hacked? What are the suggested precautions for the average user?
1
vote
1answer
329 views

How many peers do you need to securely synchronize with the blockchain?

What is the minimum number of peers required to securely synchronize my local blockchain copy?
3
votes
3answers
5k views

Can we report a fraudster by their bitcoin wallet address?

I was recently notified by a friend that someone sent her a message (posing as me) on an app asking her to send them some bitcoin so they could make a purchase. Luckily she knew it was not me and let ...
0
votes
2answers
193 views

How can address' hash160 be used to determine information for malicious purposes? (Ie reusing of the same address)

I've been playing around with Richard Kiss's Pycoin app which is clarifying how P2PK works. I see that the hash160 of the value: (0x04) (x-coordinate) (y-coordinate) (for an uncompressed Testnet ...
0
votes
1answer
12 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
1answer
144 views

How to store private key in MySQL database?

I want to receive payments from Bitcoin on my web app, but I do not want to use corporate gateways (coinpayments, bitpay, etc), I'm wanting to make my own gateway. I do not know how best to do this ...
2
votes
3answers
1k views

ECDSA x,y coordinate validity verification doesn't seem to work

The ECDSA algorithm, secp256k1 for Bitcoin allegedly uses the equation y ^ 2 = x ^ 3 + 7 mod P to determine the validity of an alleged point upon the elliptical curve. Utilizing http://web2.0calc....
1
vote
1answer
33 views

Delegated Proof of Stake (DPOS) vs. Proof of stake?

What is the main difference between Delegated Proof of Stake (DPOS) vs. Proof of Stake? Is there any significant advantage for security? (since PoS in general suffers security problems.) And which ...
0
votes
3answers
486 views

Is creating a long password for my coinbase account enough to keep my bitcoins secure?

I've made an account with coinbase and purchased some bitcoin. Only after to start reading people talk about getting hacked and how bitcoins are not secure unless you put them in a "wallet".To be ...
0
votes
1answer
24 views

Statement: for an attacker to change history, they must solve computational puzzles at a faster rate than the rest of the participants combined

I'm new to cryptocurrency and blockchain. I just started reading the textbook Bitcoin and Cryptocurrency Technologies by Narayananm, Bonneau, Felten, Miller and Goldfeder. The statement in the title ...
3
votes
1answer
33 views

Question about identical txids/merkle tree in Developer guide

I am new to the technical details about Bitcoin and has been reading Developer guide on bitcoin.org. I have a question about below contents mentioning merkle tree, identical txids. I googled and ...
1
vote
2answers
41 views

Do lightweight wallets validate signatures? If not, why?

I've learned that "some SPV clients simply don’t check signatures themselves at all": https://bitcoincore.org/en/2016/01/26/segwit-benefits/#efficiency-gains-when-not-verifying-signatures I wonder if ...
3
votes
1answer
779 views

How does timejacking enable double spending?

http://culubas.blogspot.com/2011/05/timejacking-bitcoin_802.html I went over this blog, but I am still not clear how double spending is achieved by this attack. From what I read, the attackers submit ...
1
vote
0answers
16 views

How to protect a crypto currency from Seed failure

I have created a new currency based on Forknote/Cryptnote. It has a small number of Seed Nodes. I am investigating how to mitigate the risks of currency failure due to Seed Node collapse from ...
0
votes
2answers
36 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?
5
votes
1answer
390 views

How can all possible numbers in 256-bit space be squeezed into 160-bit space?

Bitcoin addresses are essentially 160-bit hashes of a 256-bit public key. Huh? How can all possible numbers in 256-bit space be squeezed into 160-bit space? Does that mean any given bitcoin address ...
2
votes
1answer
63 views

Is there a limit to how many blocks can be rolled back from a 51% attack?

I was wondering if we where to ever face a 51% attack is there some sort of limit as to when the longest chain doesn't matter? For example if I owned 51%+ of the network, mined 1000 blocks privately ...
3
votes
3answers
123 views

Has PoS really been proven secure under comparable assumptions as Bitcoin?

I am just reading this paper which claims to be a formal proof that Cardano's latest Ouroboros PoS protocol ("Genesis") gives similar security guarantees than Bitcoin's PoW protocol. Unfortunately, it ...
-1
votes
1answer
1k views

How to hack a Password of Private Key

I have a Private key and then after I entered it, there's another saying "Input a required Password of Private Key" So how can I hack or generate that?