51% attack can be done with no source code access?

[wsxdrfv]

If some coin does not open its source code at github, and just open its windows/linux wallet only,

then some attacker can do 51% attack? with just mining power? how?

[1714109320]

1714109320

[1714109320]

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[bob123]

If some coin does not open its source code at github, and just open its windows/linux wallet only,

If some coin is not open source, it is a full shit coin.
Don't expect anyone to even spend 5 seconds thinking about this shitcoin.

then some attacker can do 51% attack? with just mining power? how?

What do you mean by 'how' ? That's self-explanatory.

I would suggest you do NOT start any project. Your technical knowledge (based on this and all of your previous threads) is almost zero.
If you have capital, hire someone. If you don't, just forget about it.

[butka]

then some attacker can do 51% attack? with just mining power? how?

As already indicated, the answer is hidden in your question. By having 51 percent of mining power. Yes, that's enough to take over the entire public ledger, to rewrite transaction history, double spend etc... No access to source code needed.

If your coin is new and your network doesn't have enough hash power, this kind of attack can pose a real danger. But then again, if your coin is new, probably nobody would be interested in performing 51% attack.

[Kprawn]

A 51% attack or double-spend attack is a miner or group of miners on a blockchain trying to spend their crypto’s on that

blockchain twice. They try to ‘double spend’ them, hence the name. You can read more about a 51% attack and how it works

at this source : https://medium.com/coinmonks/what-is-a-51-attack-or-double-spend-attack-aa108db63474 (You can only

do this, if you have more than 51% of the hashing power for a specific Blockchain) 

[vit05]

51% Attack is only a problem for decentralized networks. A centralized, closed-source network would never face this. The 51% attack is an attempt to dominate the network and dictate what is true or false.

What many people confuse, is that it's all about trust. In Bitcoin, everything works without the need to know all the actors. This is due to the possibility of testing the code and verifying it. No matter who you are. That is, at all times a network of confirmations occur validating the whole process

In a closed code, few would know what actually happens. What changes are occurring. There is no need for a 51% attack since there are already a few controllers. In EOS this is what happens, a small group controls everything. At Ripple is a single foundation.

[wsxdrfv]

51% Attack is only a problem for decentralized networks. A centralized, closed-source network would never face this. The 51% attack is an attempt to dominate the network and dictate what is true or false.

What many people confuse, is that it's all about trust. In Bitcoin, everything works without the need to know all the actors. This is due to the possibility of testing the code and verifying it. No matter who you are. That is, at all times a network of confirmations occur validating the whole process

In a closed code, few would know what actually happens. What changes are occurring. There is no need for a 51% attack since there are already a few controllers. In EOS this is what happens, a small group controls everything. At Ripple is a single foundation.

So if mostly same with just bitcoin source code, then? Just not open to public for example. Still other 51% owner can ruin the network?

[DarkStar_]

If there was just a wallet (presumably an SPV wallet or one that doesn't run a node?), I don't believe a 51% attack would be possible because no one knows how to mine it. That would require probably a single centralized 'node', which is pointless. You get the complications of blockchain, and the security of a normal database.

I don't believe you need to modify source code to run a 51% attack; you could solve a block, and just not broadcast it.

[Heisenberg_Hunter]

I would suggest you do NOT start any project. Your technical knowledge (based on this and all of your previous threads) is almost zero.

are you trying to make your own cryptocurrency since i've seen you make similar thread (about various technical detail about bitcoin specifically)

You guys are late, I guess. They have already created a clone 5 months ago  and named it as Bitcoin Essence with minor source code changes and total supply. The coin is even available in 2 exchanges 

ANN Thread : https://bitcointalk.org/index.php?topic=3108135.0
Website : https://www.bitcoinessence.org

So if mostly same with just bitcoin source code, then? Just not open to public for example. Still other 51% owner can ruin the network?

Op no one would mind launching a 51% attack on your clone coin(assuming you are the dev of the BTE). I guess you might be the sole miner of your coin, so it's in your hands to destroy your clone coin or not as they don't even have a value and volume out their in the 2 exchanges. 

P.S Before getting into further development and updation of your clone, you should read and understand the basics of cryptography. You should give a read on Mastering Bitcoin/Princeton Book and get a basic understanding of technically how bitcoin works.

[Rath_]

i cant understand this 51 percent attact , can anyone explaine to me !

This Bitcoin wiki article should help you to understand it.

I don't believe you need to modify source code to run a 51% attack; you could solve a block, and just not broadcast it.

Not even a single block. The attacker can perform a private hard fork which could overwrite the original chain once it became longer. This attack would be obviously used for cheating merchants and could be performed with a lower hashrate but has a lower success rate.