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.

-1
votes
0answers
9 views

I was threatened

I am not dealing with Bitcoin. I received the following e-mail. ” I am well aware XXXXXX one of your password. Lets get straight to purpose. You do not know me and you're probably wondering why you ...
1
vote
1answer
12 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 &...
1
vote
1answer
23 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
39 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
2answers
35 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 ...
0
votes
0answers
20 views

Blockchain Security [closed]

I have problem with security of my blockchain wallet. So I have a service where users can generate addresses and bring some coins to our platform, and instead get bonuses. What I did was run ...
0
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
1answer
41 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
51 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
68 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 ...
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
80 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 ...
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
29 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
1answer
31 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 ...
3
votes
1answer
768 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
11 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 ...
2
votes
1answer
45 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 ...
1
vote
1answer
24 views

Possibility of broadcasting new block to only a fraction of honest nodes?

Consider in a block-withholding attack (aka selfish mining attack), attacker after creating a new block decides to broadcast this new block only to a fraction of network, such that eventually only a ...
5
votes
1answer
389 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 ...
0
votes
2answers
31 views

How to secure a Linux node running satoshi 0.16.1?

Everyone in the BTC space seems to suggest that running a full node is the way to go. But Linux has a huge attack surface and I don't want to lose my BTC by having my wallet on an insecure OS. What is ...
3
votes
3answers
110 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
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 ...
0
votes
2answers
64 views

i lost access to my bitcoin [closed]

I did not have any idea about bitcoin but I wanted to get in, I met this guy who knew about it on facebook asked him if he could help. he sent me the link on blockchain to signup showed me how to buy ...
2
votes
1answer
45 views

Checking the first and last characters of a cryptocurrency address?

When confirming that an address entered on a site/app is what I expect it to be, I often check the first and last 3-4 characters to see if they match. Is this practice dangerous? Could an attacker ...
3
votes
1answer
50 views

Why is it more profitable for a node with more than 51% computation power to abide by the rules in the bitcoin network

The Bitcoin whitepaper states - "The incentive may help encourage nodes to stay honest. If a greedy attacker is able to assemble more CPU power than all the honest nodes, he would have to choose ...
2
votes
1answer
74 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 ...
0
votes
1answer
122 views

Hello, someone is using an 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 ...
-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?
0
votes
3answers
44 views

Am I protected?

I've been asked to pay for a purchase in Bitcoin. Why would someone use this method instead of say Paypal and as a consumer am I protected in any way? I have never used Bitcoin or looked into it so I'...
4
votes
3answers
131 views

How can I safely store and trade Bitcoin and other crypto currencies?

How can I safely store Bitcoin? Exchanges require me to deposit to trade, is this safe? If I can't trust exchanges, what is the best way to safely store my cryptocurrency and transact it?
1
vote
1answer
41 views

Given that you have the necessary computing power, how does a tampered blockchain get accepted by the network?

I read that you can only tamper with a blockchain if you have more than 50% of the computing power in the network. So say you have 51% of the computing power, then you can create a longer blockchain ...
1
vote
1answer
46 views

Is Lightning network really a hope for better scalability and low latency?

BTC can't do transaction in 1/4000 times to what VISA does and then still claims that it will disrupt industry. The proof of work has limitations to scalability and in no way it can record transaction ...
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
83 views

Why do the biggest exchanges reuse Bitcoin addresses if doing so is unsafe?

It's generally accepted that using one address for multiple transactions is unsafe, because sending a transaction reveals your public key (whereas only the hash of your public key is required to ...
0
votes
1answer
31 views

How bitcoin wallets connected between

I'm thinking, is it dangerous to buy bitcoin, in case if government want to block it? How bitcoin wallets connected between? If I'm right - there are support servers, who providing connection between ...
5
votes
1answer
199 views

How do the JavaScript SecureRandom() vulnerabilities affect me?

A recent post on the Bitcoin-dev mailing list talks about multiple vulnerabilities in JavaScript SecureRandom() class. Apparently this class has been used in multiple cryptocurrency wallets that use ...
11
votes
2answers
2k 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 ...
0
votes
2answers
55 views

What prevents broadcasting of fraudulent transactions

I see a lot of questions and articles about why someone can't generate fake coins, maliciously attack the network, and essentially security discussions focused on the generation and interception of ...
0
votes
2answers
39 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 ...
2
votes
1answer
73 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 ...
0
votes
1answer
69 views

Could BitCoin network be destroyed if blockchain would get corrupted?

This thought came to me whilst watching mr. Robot where the entire database of a financial corporation has been encrypted. Would that (in theory) be possible if a virus was spread that would target ...
8
votes
3answers
891 views

Miner modifies unconfirmed transactions and put it into the block

Is is possible that a miner modified a unconfirmed transaction (like changing the output of transaction to the miner himself) and put it into the local block, and after 10 mins the miner luckily ...
1
vote
1answer
60 views

Is “fee higher than block reward” attack possible?

Imagine the following scenario: I send you 1000 BTC. After 6 confirmations, you give me what I bought. I create another transaction with 900 BTC to my own wallet and 100 BTC as transaction fee, using ...
0
votes
1answer
77 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....
-1
votes
1answer
140 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 ...
0
votes
1answer
58 views

How Bitcoin wallets avoid address re-usability?

As we know, address reusability compromises both privacy and security. My question is how Bitcoin wallets avoid address reusability? Is wallet generates an address from index 1 and scan blockchain ...
1
vote
1answer
139 views

Forking Bitcoin how to prevent a 51% majority attack

Lets say I fork Bitcoin, to lets call it StackCoin. How do I prevent a 51% majority attack when miners are not in abundance? Would I have to setup a lot of miners to create the infrastructure of the ...
1
vote
2answers
219 views

How to check if a program is mining crypto in the background

I noticed a program I recently downloaded cause my CPU usage increase by 30 percent and 80% GPU usage increment in idle state. It is not a GPU intensive program at all. I am worried about it using my ...