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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
108 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
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1answer
32 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
208 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
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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 ...
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2answers
73 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 ...
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2answers
44 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
101 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
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1answer
73 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
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3answers
928 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
66 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
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1answer
83 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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1answer
166 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
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1answer
66 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
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1answer
162 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 ...
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vote
2answers
329 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 ...
0
votes
0answers
175 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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2answers
40 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?
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2answers
256 views

Private key security level

Any of a kind Bitcoin wallet need to share private key on the internet-connected machine. Bitcoin client has no responsibility for to keep private key secure. If your's machine connected to the ...
-1
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2answers
3k views

Binance hacked?

Something is happening, yesterday in reddit many people could not withdraw their funds or cancel their purchase orders . And the administrator (who is binance and usually solves the problems) erased ...
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0answers
50 views

How does the bitfury crystal software works?

Can someone explain to me how the crystal software works? The transfers made using multiple wallets are anonymous and not traceables?
1
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1answer
243 views

Safely transferring from a paper wallet [closed]

I am holding for the long term and have a significant amount of bitcoin (~10) in a paper wallet (the actual private key is printed on a piece of paper). To improve security measures and possibly sell ...
1
vote
1answer
47 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
1answer
145 views

In what sense does the security model of proof-of-stake require users to “log on to the internet every few months”

This is primarily a question about something I heard Vitalik Buterin say in an interview the other day. (Unchained podcast's January 9, 2018 episode, at 34 minutes, 15 seconds) I quote: As far as ...
0
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1answer
110 views

Why doesn't Multisig provide better security for hot wallets?

I've recently read somewhere (can't remember the source) that multisig often doesn't provide more security in hot wallets, but increases the size and thus the fee. I can't seem to comprehend how ...
0
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1answer
248 views

Who maintains list of bitcoin nodes and aren't they a weak link in the security of the system?

I understand that between the people who run Bitcoin nodes, and therefore the Bitcoin protocol, the system is trust-less and secure. However, there seems to be a weak link - the official list of ...
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2answers
74 views

Which one is more effective for attacking the system, controlling 51% of the mining power or 51% of the full nodes?

I used to think it is the miner who verify the transaction, but it turns out this is really a joint work by the miner and the full nodes; the miner broadcasts the newly discovered block, which ...
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1answer
36 views

Can a cryptocurrency be “decapitated”

Say the first n blocks on the block chain were mined by the creator of the currency. What's to stop everyone unanimously deciding to ignore those first n blocks at a later date and therefore "...
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vote
4answers
237 views

Is it wrong to spend Bitcoin from someone else's wallet if my Bitcoin client generates the same address?

I know this scenario is extremely unlikely but what-if by chance I get the same Bitcoin address as another user and the user has hundreds or thousands of Bitcoins in his wallet, is it morally/legally ...
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2answers
852 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 ...
0
votes
1answer
249 views

Lost my phone with the wallet in it… Any way to recuperate my 5.178 bitcoins? [closed]

Phone and car got stolen, i had the keychain of my wallet on a pad, so it's all gone, everything!! Please tell me there's a way to get them back?
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6answers
1k views

How do I protect my paper wallet from use by a different human who has used a random generator?

Since millions of people use Bitcoin and Bitcoin Wallets that use their own addresses use several addresses per day, it is obvious that generators can generate the same characters for the Bitcoin ...
0
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1answer
68 views

Non-Bitcoin blockchain security questions

I've been seeing a lot of stories lately about companies wanting to use blockchain, I've got two questions regarding companies using blockchain networks to store transaction ledgers. With Bitcoin, ...
1
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2answers
160 views

What prevents a miner to change the locking scripts of an unconfirmed transaction

In many cryptocurrencies a TX is composed of an array of TX inputs and TX outputs. When a TX is submitted to the network, it already has the signature (in the unlocking script). So my question is, ...
0
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1answer
809 views

scammed by a scammer [closed]

First of all, this is to bring awareness of how an attacher may gain access to a persons' Blockchain Wallet: i hope this never happens to anyone else but it probably will. i am quite new to bitcoin, ...
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2answers
134 views

Extra security for paper wallets

I want to transfer my bitcoin to a paper wallet for long term storage. However, with the risk of fire/theft etc. I'm not comfortable holding it as a paper printout. So my question (sorry if its too ...
3
votes
1answer
119 views

Is my wallet effected by the Meltdown and Spectre vulnerabtilies?

Recently two new vulnerabilities, Meltdown and Spectre were published which lets someone read more memory than they are supposed to be able to. How does this effect my wallets and what can I do to ...
-1
votes
1answer
1k views

How can I cancel a pending transaction

https://blockchain.info/tx/d2aa8e971dd26a4f4598f57b55e921a62fa376dad1cf25e426b6ba7d79052466?show_adv=true. This transaction was made by some fraudsters on my wallet. I later recovered my wallet. How ...
3
votes
3answers
7k 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 ...
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3answers
220 views

How can Bitcoin be stolen?

If each bitcoin has a ledger (Peer to Peer) and contains all the transaction history since it was mined, then how come it can be stolen? For example, Bitcoins were stolen by hackers from Mt. Gox. If ...
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 ...
0
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1answer
580 views

How will Lightning Network nodes secure their hot wallets?

The success of the Lightning Network is dependent on payment routing. Successful payment routing will require online nodes with automated signing facilities. This entails online nodes with hot wallets....
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2answers
1k views

Ripple paper wallet: is “ripplepaperwallet.com” safe?

I've been reading on the internet and I have found several websites for generating Ripple paper wallets: ripply.eu, bithomp.com, gatehub, etc. I'm not sure if these websites are official Ripple ...
0
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1answer
30 views

Storing wallet key for automatic transactions

Is there any way to do this? For example I don't even want to know what my wallet is, only my server (intranet), so that it can make automatic transactions for me based on thresholds. Or should I not ...
0
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2answers
88 views

are individual satoshis as secure as an overall bitcoin?

I don't really understand Bitcoins as well as I'd like. I understand that eventually there will be 21,000,000 bitcoins mined. And, I understand that each bitcoin can be subdivided into 100,000,000 ...
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1answer
41 views

Month into crypto and have some questions

I've been invested in btc, eth, and ltc for about a month on Coinbase. I'm still working to learn about this expansive realm. I don't totally understand the need for a wallet and how that works. ...
1
vote
1answer
51 views

How do I know if the Bitcoin page has been hijacked [closed]

With so many hackers hijacking websites these days, what do I look for to show me that I'm not on a hijacked page?
1
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1answer
59 views

Transforming existing private key into new private key?

Is it possible to derive a new private key from an existing private key and retain the same bitcoin balance without any transactions?
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1answer
620 views

Bitcoin is becoming CENTRALIZED and is INSECURE [closed]

I'd like someone to tell me if I'm wrong: More than 50% of the mining is done by Chinese pools. That means that they control the network - who's transactions get in, who's transactions are left out. ...
2
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1answer
602 views

Are received BTCs really mine?

when somebody send me BTCs I recognize that by seeing a transaction output is equal to my address. But how can I be sure that it's really me and only me who can spend the output? I can check, I can ...
0
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1answer
132 views

What would happen if every miner adds a transaction to his block that did not occur?

Let's say every single miner in the world added the same transaction to their block via trickery. The transaction was never initiated by the wallet holder. Would a block from these miners be added to ...