Topic: Raspberry Pis Full node and Double spending problem (Read 226 times)

this note about Sybil attack (which you try to do with you raspi-army) is coming from https://en.bitcoin.it/wiki/Weaknesses that means your raspi-army could still be harmful to the entire network:

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Sybil attack

If an attacker attempts to fill the network with clients that they control, you would then be very likely to connect only to attacker nodes. Although Bitcoin never uses a count of nodes for anything, completely isolating a node from the honest network can be helpful in the execution of other attacks.

This state can be exploited in (at least) the following ways:

- the attacker can refuse to relay blocks and transactions from everyone, effectively disconnecting you from the network
- the attacker can relay only blocks that they create, effectively putting you on a separate network and then also leaving you open to double-spending attacks
- if you rely on transactions with 0 confirmations, the attacker can just filter out certain transactions to execute double-spending attacks
- low-latency encryption/anonymization of Bitcoin's transmissions (with Tor, JAP, etc.) can be defeated relatively easily with a timing attack if you're connected to several of the attacker's nodes and the attacker is watching your transmissions at your ISP

Bitcoin makes these attacks more difficult by only making an outbound connection to one IP address per /16 (x.y.0.0). Incoming connections are unlimited and unregulated, but this is generally only a problem in the anonymity case where you're probably already unable to accept incoming connections.

Looking for suspiciously-low network hash-rates may help prevent the second one.

To extend on achow101's comment: The attack scenario you describe is also known as a Sybil attack. It's one of the reasons why Proof of Work was introduced as a consensus mechanism -- it's relatively easy to fake being multiple peers (e.g. by using thousands of Raspis), but it's impossible to fake Proof of Work.

They don't really.

There is no maximum number of nodes on the network. There is not and cannot be a maximum.

It doesn't matter. Double spends are resolved by miners, not non-mining nodes. The number of nodes doesn't matter.

If you are a miner, you could double spend your own coins. Note that it isn't really a true double spend. You are not actually spending the same coin twice; rather you are simply spending the same coin in two transactions and only one of those transactions becomes final when it is included in the blockchain, presumably by you. However. double spending as a miner requires a significant amount of hashrate so the initial investment in mining hardware is very large and infeasible for most people.

How can Nodes protect me from Double spending? What if i have like 10000 and ever more of Raspberry Pis at my home and therefore the maxm. no. of nodes in the network wid all of them saying DOUBLE SPENDED transcation is the real one??? Would it mean, if i as i miner, successfully double spended my coins?