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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
67 views

“Hot”, “Cold” & “Warm” Storage Wallets? [duplicate]

I've seen a number of sites advertise they support "hot", "warm" and "cold" wallet storage solutions (the only thing I haven't seen so far are "frozen" wallets)....
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1answer
244 views

Are Hardware Wallets (i.e, Ledger Nano X) Safer than Software-Based Cold Storage Wallets?

I'm looking into purchasing Ledger Nano X as a cold storage hardware solution. What benefits does Nano X (or other hardware wallets) provide over software based cold storage solutions? Why not install ...
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1answer
89 views

How do exchanges automate transfer of Bitcoin from a cold storage wallet?

Most exchanges use Cold Storage to store the bulk (approx. 95%) of their user assets. Only a relatively small amount (approx. 5%) of funds are held in their Hot Wallet. My question is, what process is ...
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1answer
182 views

Securing the “weakest link” of a chain through Sharding

In this question I discussed how sharding a private key with Shamir's Secret Sharing Scheme maybe a good alternative to MultiSig as a means of reducing excessive fees associated with MultiSig ...
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1answer
46 views

Security concerns with walletpassphrase

I have some security concerns with walletpassphrase: If it stores the passphrase for some unit of time. ie. so you can send funds, surely if the server is compromised, within that timeframe, the ...
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1answer
219 views

Is Sharding a Good Alternative to MultiSig?

For security purposes, we require that each withdrawal be "approved" by multiple servers so that in the event a single server is compromised the attacker won't be able to siphon funds from ...
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1answer
33 views

What does it means “get a new address and then make the Bitcoin offline” and make it extremely secure?

I have been reading about Bitcoin, and one thing was about making Bitcoin extremely secure, which is to get a new address so that nobody knows, and then making it offline right away? Is it like 0.01 ...
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1answer
21 views

Can an exchange or marketplace benefit from private key encryption?

A powerful security technique to prevent theft of Bitcoins from a user's online wallet is to encrypt the user's private key with his password without ever stroring the PK directly in the database. ...
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1answer
48 views

Storing your private key on a “security server”?

One of the suggested security precautions when storing Bitcoin of users on a server is to store the private keys on a separate server: The database storing the private keys or the seeds in case of ...
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1answer
58 views

How can I earn an income from my bitcoins without revealing my identity or relinquishing control of my bitcoins? [duplicate]

I have some Bitcoin. I don't want to part with them, but I need an income. I'm trying to have it so that, somehow, my Bitcoins generate a small sum monthly in fiat, to my bank account. While going ...
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3answers
383 views

If the “wallet seed keywords phrase” is all that's needed to restore a hardware Bitcoin wallet, isn't backing that up a nightmare security-wise?

I buy a Trezor. I put all my coins on it. It has me type out the "wallet seed", which is a series of English words in the right order, onto a paper. And maybe I even buy a metallic card ...
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2answers
146 views

Lessons from the Mt. Gox Hack - 850,000 Bitcoins Stolen

Mt. Gox was a bitcoin exchange based in Shibuya, Tokyo, Japan. Launched in July 2010, by 2013 and into 2014 it was handling over 70% of all bitcoin (BTC) transactions worldwide, as the largest bitcoin ...
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5answers
77 views

Are ASICs Resistant to Malware Attacks?

One of the arguments made in favor of relying on ASIC mining hardware to secure the Bitcoin blockchain is that commodity hardware is more prone to a 51% attack since an attacker could easily infect ...
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2answers
2k views

Is there something about Bitcoin that prevents us from implementing the same privacy protocols of Monero and Zcash?

Certain coins like Monero and Zcash implement privacy protocols that make it nearly impossible to trace origin and destination of transactions - making them completely anonymous. I'm curious as to why ...
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2answers
99 views

What stops an attacker from crippling the Bitcoin network?

An individual (or government) who wants to bring down the Bitcoin network could conceivably broadcast a ton of junk/illegitimate transactions to the network thereby consuming the bandwidth and ...
2
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1answer
156 views

Would first-seen prevent a double spend attack?

It takes approx. 8 seconds for a transaction to propagate through the entire Bitcoin network. If we got rid of the concept of replace-by-fee and replaced it (no pun intended) with a first-seen ...
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1answer
218 views

Recover $220 Million Worth of Bitcoin Locked in a Self Destructing Hard Drive

A NY Times article recently ran a story of Stefan Thomas who has $220 million worth of Bitcoin locked up in an encrypted hard drive: Stefan Thomas, a German-born programmer living in San Francisco, ...
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2answers
81 views

1 MB Block Size as a Anti-DoS Attack Measure

Wikipedia explains the rationale behind the 1 MB block size limit as follows: The one megabyte block size limit was added in 2010 by Satoshi Nakamoto as a temporary anti-DoS measure A SE post ...
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1answer
78 views

Is my cold wallet still cold?

I created a new wallet.dat on a dedicated, secured machine with Bitcoin Core. Then I encrypted it. Then I sent my "fortune" of coins to it. Then I backed the file up by putting it on all my ...
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0answers
34 views

Bitcoin over Tor and man in the middle attack: risks mitigated yet?

This paper explains how combining Bitcoin and Tor creates an attack vector. A man in the middle can control the information flow between all users who connect over Tor. This paper is from 2014. Has ...
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2answers
118 views

Mining Bitcoin at 1000x Efficiency

Bitcoin secures its network by forcing miners to solve a cryptographic puzzle who's difficulty increases based on the total hashing power of the network. If someone were to develop an algorithm that ...
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1answer
167 views

Doesn't storing the “recovery seed phrase” for a wallet defy all logic?

I've heard many times that you are supposed to write down a "recovery seed phrase" (a series of English dictionary words) on a piece of paper and store that securely so that you can recover ...
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1answer
70 views

Why can't a 51% attack change past blocks on the blockchain?

I have read that it is not possible to reverse transactions already added to the blockchain but I do not understand why that is not possible in a 51% attack. If an attacker was to change the ...
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0answers
43 views

What should i do with my used antminer? How should i set it up?

ive just purchased a 2nd hand s9i antminer, got it for £200, a great deal i thought, what tasks should i perform before installing? i was thinking of opening it up and looking inside, just to see what ...
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1answer
21 views

What is the practical link between the hashing power in the bitcoin network and its security? [duplicate]

Several books claim that as the hashing/computing power increases, the bitcoin network is securer. How can a non-techie sees that from a practical standpoint?
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3answers
38 views

Do hardware wallets store the wallet.dat redundantly inside? If not, are there such hardware wallets?

I'm baffled by how "cheap" the existing hardware wallets look and seem. They seem to have been made "at a budget", with no real high-end version available. If I owned something ...
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3answers
3k views

Is bitcoin.org or bitcoincore.org the one to trust?

"Download Bitcoin Core": https://bitcoin.org/en/download "Download Bitcoin Core": https://bitcoincore.org/en/download/ I've been alternating between the two sites for years. I have ...
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2answers
135 views

What prevents somebody from “re-mining” an already existing Bitcoin?

This may reveal that I know nothing about math or cryptography. Let's say that a given Bitcoin was "lost" in that it was once mined and assigned/given to a person who had it in their wallet....
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2answers
271 views

Should I be using the “encrypt wallet” feature in Bitcoin Core?

All my wallet.dats have no password. However, the internal hard disk where the "live" one is located is encrypted, and so are the offline storage devices where I have my "cold" ...
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2answers
164 views

Am I really understanding how the “Trezor Model T”, and hardware wallets in general, work?

Getting increasingly paranoid about losing my coins, I've yet again (for probably the 20th time by now) went looking for hardware wallets. The only semi-reasonable one seems to be the two Trezors. All ...
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1answer
83 views

As the Bitcoin price skyrockets, how to avoid getting malware through freeware/FOSS software's updates?

We have a situation now where the vast majority of software I have installed on my computer (Windows 10, since there are no other supported versions of Windows) are either aging one-man freeware ...
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2answers
56 views

Threat probability? 1 state controls >70% of miners. Other states go to war with them [closed]

This is almost certainly a silly question, but there are a lot of new bitcoin owners like me and a specific threat was made today which sounds credible to those of us who lack deep knowledge of ...
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5answers
3k views

How to transfer bitcoin? No third party, no exchange, no hard wallet, no mobile wallet

I have two paper wallets and want to transfer 10 bitcoins between them. I do not want to use any other 3rd party software or hard wallet because they're created by individuals, so they can access my ...
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1answer
96 views

How to reverse Bitcoin Elliptic curve?

Hello Friends is this possible to reverse the elliptical curve if you have value of X and Y of public key? I know the public is generated through following formula K=kG or kG=K Can we reverse it ?
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2answers
59 views

How would I prove that I own X amount of Bitcoin to somebody without violating my privacy or sending/risking any coins?

Now that people who own a full Bitcoin will be like people who currently own ten million USD or more in "liquid assets", I'm trying to come up with some way that I can safely and reasonably ...
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1answer
40 views

is wallet vulnerable when unlocked for transactions?

is wallet vulnerable when unlocked for transactions?.I recovered a wallet some time ago and all is good.passphrase key all looks good.But a question came to my mind about the moment we make a ...
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1answer
45 views

Stealing a correct hash because of an invalid block

Suppose that a miner find the right hashes but involuntarily or by malicious intention then create an invalid block, like trying to double spend a transaction My guess is that the moment this block is ...
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0answers
51 views

Can you think of a safe way to safely keep my “spendable” Bitcoin in my situation?

I have my "cold stash" wallet.dat on multiple fully offline, encrypted hard disks/sticks inside a fireproof safe. I never seriously considered printing them onto paper because that would be ...
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1answer
73 views

What is the alternative for an exchange which doesnt want to run a node of a coin traded?

It seems to be best practice for an exchange to run a node itself for a coin traded there. But, is there an alternative? A third party service? If yes, which are recommended and why?
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2answers
110 views

What are the benefit of mining an empty block

Something peculiar just happened on the newly mined block number 655534, it contain only the coinbase transaction, nothing else. I have searched for a similar question but only found this one Why ...
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3answers
357 views

Accidentally reused bitcoin address

I've understood that address reuse undermines privacy and potentially also security in the future. Recently though, I accidentally reused the same public address when receiving funds from an exchange. ...
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0answers
54 views

When a BIP44 XPUB and one of its descendant keys get leaked, what's the worst that can happen?

I understand that BIP44 has one edge case vulnerability where if a hacker gets his hands on an Xpub and a private key from its descendants, he can compute the Xprv pair of the original Xpub and ...
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3answers
752 views

Security risks with running bitcoin core, and how to protect yourself

I'm new to bitcoin and want to help the network by running a full node. I plan to download bitcoin core from the bitcoin.org website, and run it on a spare laptop, by my concern is how do I protect my ...
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1answer
74 views

How can Forks and Orphan Blocks be used to attack a Blockchain?

So I'm trying to learn about the security aspects of Blockchains and one of the papers I'm reading (https://arxiv.org/pdf/1904.03487.pdf) states that Forks and Orphaned Blocks can be used to attack a ...
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1answer
77 views

What is an uninitialized read? Can you point out some examples found in Bitcoin Core? How do you detect them?

What is an uninitialized read? Can you point out some examples found in Bitcoin Core? How do you detect them?
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1answer
45 views

How does the security of a mobile wallet work?

Let's assume we have a non custodial hd mobile wallet. Where is the master key stored? What are the components of the telephone that allow the derivation of keys?
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1answer
40 views

Where are the exchange keys kept? [closed]

Following what happened in Kucoin, a doubt arises. Where are the exchange keys kept? Are HSMs not used for key storage?
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1answer
72 views

Is the Lightning Network sufficiently secure and well tested for wumbo channels?

Has the Lightning Network reached a level of security and maturity where I can open wumbo channels (channels over the previous 0.1677 BTC limit) and be reasonably confident that I won't lose funds or ...
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2answers
255 views

How to create watch-only wallet on a server with a full node?

Given: there're online shops and a server with a full BTC node that I plan to run. I'll be using a full node to monitor incomming transcations thus receiving payments in an automatic manner. Only. ...
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1answer
71 views

Should I Encrypt my Wallet for Cold Storage?

I understand that the Bitcoin QT wallet is already encrypted to some extent when I use a password. Is it best-practice to further encrypt the wallet file for long term storage?

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