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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2answers
102 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....
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4answers
351 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
36 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 ...
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0answers
25 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 ...
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1answer
742 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
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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 ...
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2answers
497 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 ...
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1answer
76 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 ...
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1answer
210 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 ...
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2answers
297 views

To what extent does asymmetric cryptography secure bitcoin transactions?

Is there a specific attack or bug which asymmetric cryptography prevents during bitcoin transactions?
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1answer
35 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
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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 ...
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1answer
50 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 ...
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3answers
587 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 ...
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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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29 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 ...
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1answer
40 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 ...
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1answer
43 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 ...
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2answers
47 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
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 ...
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2answers
577 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 ...
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2answers
149 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 ...
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1answer
43 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 ...
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1answer
246 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 ...
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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 ...
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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 ...
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3answers
72 views

Bitcoin scam artist

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
8k 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? ...
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1answer
5k views

What happens to Bitcoin wallet / Bitcoins if PC is stolen

I am a beginner and just starting to explore the possibilities of Bitcoins. So I would be very grateful if somebody could help me with this question. Is there a risk that my Bitcoins are lost if the ...
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1answer
72 views

How much of the Bitcoin Source code is untouchable? [CVE-2018–17144]

My understanding is that CVE-2018–17144 (inflation bug introduced in 0.15) was partially a result of how convoluted the original code is. Regardless of the specific CVE-2018–17144 example, are there ...
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1answer
297 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 ...
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2answers
152 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 ...
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1answer
129 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
576 views

Lightning network and lightweight clients

How will the lightning network handle lightweight clients? Do I understand it correctly that opening a payment channel require writing on the blockchain to protect against double-spend? The integrity ...
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1answer
67 views

Does LN require an on-chain “emergency lane” to mitigate systemic risks?

According to LN social slides, a fee market (in other word: "congested mempool", to my understanding) is good. But, there's systemic risks around penalty mechanism, so some sort of on-chain scaling (...
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1answer
4k views

Why is JSON-RPC over SSL “strongly discouraged”?

The Wiki contains a page that simply states: JSON-RPC over SSL is strongly discouraged Why? I found a method for enabling JSON_RPC over SSL here. The post mentions nothing about JSON-RPC over SSL ...
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2answers
121 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 ...
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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 ...
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1answer
43 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 ...
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2answers
105 views

What’s the purpose of checking for input overflow?

Everyone knows this famous fix for block 74638 which still exists in other files. But there’s something I can’t understand, why check for inputs overflow since it’s not possible to have enough utxo ...
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1answer
88 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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2answers
63 views

Why was noise XK fundamental pattern chosen in the transport layer (BOLT 08) of the lightning network

I am currently reviewing the transport layer of the Lightning network protocol. It builds on top of the noise protocol framework handshake patterns. What I don't get: Why was the fundamental pattern ...
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0answers
11 views

Does Bitcoin security rely on the assumption of nearly continuous transactions? [duplicate]

So for an attacker not to overcome good nodes, I believe we rely on the fact that blocks are always being produced, making the attacker essentially outpaced. But in the extreme and ridiculously ...
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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 ...
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1answer
40 views

Automatically close the bitcoin-qt when enable SSL for RPC

I Just try to enable SSL for bitcoin-qt RPC call. I follow the SSL on RPC link to archive my target. But I am getting the following error and close the bitcoin-qt automatically. I am using the ...
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1answer
30 views

How does the Blockchain detect a cheater, who manipulates the blockchain?

Let's assume we have 100 blocks. One miner x has the intention to manipulate block 90. So he has to recalculate the hash for block 90. Following he also has to recalculate the hashes for block 91-100. ...
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1answer
45 views

Malicious full nodes causing denial of service attacks

To control >51% of the mining power in bitcoin is impractical due to the immense investment that will be required. Also, The Bitcoin Core client has DoS protection against malicious nodes forwarding a ...
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1answer
260 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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secure Multi-Party Computation (sMPC) in Enigma?

In Enigma whitepaper (>> Link to the Enigma paper <<), in section 5.1 "Overview of secure multi-party computation", page 4, explains how to divide a secret s into multiple shares, using ...
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1answer
68 views

Private key generation doubt

I read that the private key pk has to be any number between 1 and n, where n is almost 10^77. Since pk' s function is practically to be used as a scalar for multiplying the generator point G, why does ...