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Questions tagged [replay-attack]

A type of an attack against the security of a system by recording its encrypted communication, and later replaying it in unmodified or slightly modified form.

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Generate BTC transaction that can't be replayed on forks

Transaction is non-segwit, P2PKH. I don't want to touch the same addresses on forks yet, but also don't want anybody to be able to replay my BTC transaction on any of the forks' blockchains. What can ...
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1answer
163 views

Does BitcoinABC implement replay protection for the upcoming November 15th hardfork

Does BitcoinABC implement replay protection for the upcoming November 15th hardfork. With the arguing between the two camps BitcoinABC and BitcoinSV will replay protection be implemented before the ...
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2answers
99 views

If I reuse the same address can a previously used transaction be reused?

I was wondering, if I used an address adr0 to spend some coins in a transaction tx0 that give the coins to a different address adr1, and eventually, after some time, I receive some (completely ...
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2answers
127 views

What prevents a malicious user creating a new transaction using signatures of an old mined transaction if the inputs have the exact same balance?

I am NOT talking about double spending. I am talking about this type of scenario: Let's say address A has 1 BTC balance initially. A valid transaction is created and for simplicity's sake, assume ...
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1answer
60 views

Is it possible to copy transactions between Bitcoin's forks blockchain?

Do Bitcoin forks share the same transaction protocol after the fork? If so, is it possible to copy/ duplicate a transaction that uses common input transactions in the other blockchain? Let me explain ...
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2answers
173 views

Why do we refer to previous transactions in each transaction?

Isn't it enough to just have the Input Address, Output Address, Amount and Signature for each transaction?
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1answer
56 views

Is there a time limit how long a signed transaction is valid?

When splitting coins from a hard fork and signing the transaction on the forked coin, is there a time/block limit when the transaction gets invalid on the BTC chain, so a potentially possible replay ...
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1answer
256 views

After being officially canceled, SegWit2x is live. Will transaction replaying be massive ? If yes what does this means?

As you know, segwit2x was officially canceled last week, but some miners decided to still go forward today, and some exchanges like coinbase plan to support the hard fork. So things will happen like ...
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2answers
103 views

Limit tx to SegWit1x or 2x chain

Given the lack of replay protection when the SegWit2x fork splits off a different chain is there a safe mechanism to broadcast a tx so that it will only be accepted by the 1x or 2x chain nodes? If ...
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1answer
111 views

Can replay transactions effect both chains? or just the minority hard fork chain?

Can a seg2x transaction be replayed on the main bitcoin CORE chain? I was reading that only the minority hard fork would need replay protection and that coins on the main majority chain would be ...
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1answer
204 views

What prevents one from replaying a BCC transaction by nulling the SIGHASH_FORKID bit?

BCC transactions are "replay-protected" by the SIGHASH_FORKID 0x40. However why can't I take one such transaction, flip off the 0x40 bit and here's a valid transaction on the BTC chain? I guess that ...
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2answers
893 views

If Btc2x doesn't have replay protection does that mean all transactions can be automatically replayed in btc2x?

I believe btc will have a lot higher economic activity at the time of the fork. If anyone sends funds in btc, what stops someone who don't like btc2x to just replay that same transaction on btc2x? ...
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1answer
160 views

Risk to Bitcoin balance when making Bitcoin Gold transactions

If Bitcoin Gold fails to implement replay protection, will I risk losing my Bitcoin when I make a Bitcoin Gold transaction? Assuming replay protection is not implemented properly, how can I protect ...
4
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1answer
180 views

How does the Segwit2x fork implement replay protection?

The creators of the Segwit2x fork claim that they are working on some sort of replay protection. What replay protection do they have and how does this replay protection work?
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1answer
1k views

How does Bitcoin Gold implement replay protection?

The creators of Bitcoin Gold claim that they have implemented full replay protection. How does this replay protection work?
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1answer
5k views

What is transaction replay and replay protection?

With everyone and their dog making new blockchains forked from the bitcoin blockchain, there is a lot of talk about replay protection. What is a transaction replay? What does replay protection do?
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1answer
151 views

Replay attacks: can a coinbase transaction be replayed?

I'm pretty sure that I understand how replay attacks work: A malicious node takes a valid transaction from chain A, and replays it on chain B. Other nodes on chain B see the transaction as valid and ...
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1answer
2k views

Bitcoin Gold Fork - Replay Protection

I was reading on replay vulnerabilities introduced by forks which only implement opt-in replay protection. Let 'X' be the 'legacy chain' (BTC) and let 'Y' be the forked chain (BTG). Now, if I ...
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2answers
117 views

Why do hard forks need special rules to allow replay protection?

I've seen a lot of methods hard forked chains use to provide both strong and opt-in replay protection so that transactions are only valid on one of the chains. Examples of such rules include using a ...
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6answers
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What would happen if you send Bitcoin (BTC) to a Bitcoin Cash (BCH, aka BCC) address?

Could someone please explain what happens if someone sends bitcoin to a Bitcoin Cash address after the August 1st fork? Would there be a way to recover them?
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2answers
593 views

How was Ethereum hard fork's replay attack was handled?

On etherum, there was a hard fork which resulted in ETH and ETC. My reading indicates that it suffered problem of replay-attack. Question: How was this problem resolved for Ethereum? In my ...
43
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1answer
12k views

How does Bitcoin Cash implement replay protection?

Bitcoin Cash says that they are providing replay protection for their fork. How does this replay protection work?
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1answer
225 views

How does Bitcoin prevent replay-attacks? [duplicate]

How does Bitcoin prevent replay-attacks for P2PKH transactions? As far as I understand, when a transaction is made to pay bitcoins to another account, the P2PKH script is used. scriptPubKey: OP_DUP ...
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1answer
670 views

How does the transaction signature prevent transaction duplication?

Let's say that Alice sends 1 BTC to Bob. We have then a signature of (Alice sends 1 BTC to Bob) with Alice private key. What prevents Bob from duplicating this exact same transaction and sending it to ...
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1answer
239 views

Does BIP148 (UASF) offer any replay attack protection?

Is there any protection against replay attacks in BIP148? Despite the popular name (UASF), it's effectively a hard fork (in the sense users with old nodes will be on a different chain), is there any ...
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1answer
237 views

How do we “exchange coins on one blockchain for those on the other”?

With Segwit and BIP-148 coming, I have been trying to figure out what's exactly gonna happen with Bitcoin after August 1, by watching videos and reading articles. One thing (among many others) ...
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2answers
213 views

Can I do a replay attack to spend my testnet bitcoin on the mainnet?

I think it would be possible to create a legitimate seeming transaction on the Bitcoin testnet that the Bitcoin mainnet would accept. I've read a bit about the ETC replay attacks, and it seems like ...
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2answers
1k views

after hard fork won't every new transaction go on both chains?

I don't understand why I'm reading that after a hard fork, the existing transactions would be on both chains but the new transactions will only be on one or the other (resulting in 2 different chains, ...
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3answers
930 views

What should I do if my friend runs a Bitcoin business but doesn't understand how it works?

My friend doesn't listen to his head of engineering and doesn't fully understand how decentralized consensus based systems like Bitcoin really work. He seems to think a new untested/buggy ...
11
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3answers
3k views

What is the best way to prevent replay attacks in the event of a bitcoin hard fork?

I originally thought it would be relatively simple to add replay attack protection (change something about how the tx hash is generated) in the event of a fork. But the BU folks mentioned that this ...