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> Miners can't just invent awithdrawal out of thin air that will sustain for 3 to 6 months in public.

A majority miner can, and is incentivized to do so.

> but [you] are not showing how DC is so very different a side chain is more vulnerable than any other part of bitcoin.

I’m sorry I haven’t been clear. My argument has nothing to do with the machinations of the sidechain. It could be a spreadsheet. How consensus is achieved on the sidechain is immaterial.

My point is about the locked coin on mainchain. That coin may be unlocked and spent by a majority miner (51%’er) who votes to give it to themselves. They can do so by building otherwise normal, valid blocks, reaping mainchain fees and subsidy along the way.

Such an attacker cannot take mainchain Bitcoin in the traditional sense (locked by private key) in the same way. To steal traditionally locked coin, the attacker must rewrite history. But to drain a sidechain, no history rewriting is necessary, just regular, profitable, forward mining.

Hope this clarifies. 🙏

Cyber Seagull 2y ago

>But to drain a sidechain, no history rewriting is necessary, just regular, profitable, forward mining. [By a 51%].

Ok, this is a little more clear.

Traditional 51% attack from the bitcoin wiki:

An attacker that controls more than 50% of the network's computing power can, **->for the time that he is in control,<--** exclude and modify the --->[forward] ordering of transactions. This allows him to:

Reverse transactions that he sends ---> while he's in control<---. This has the potential to double-spend transactions that previously had already been seen in the block chain, affecting all coins that share a history with the reversed transaction

Reverse confirmations for any transaction that had previously been seen in the block chain ---->while he’s in control.<-----

Prevent some or all transactions from gaining any confirmations [forward]

Prevent some or all other miners from mining any valid blocks

The attacker can't:

Reverse other people's transactions without their cooperation (unless their coin history has been affected by a double-spend)

Prevent transactions from being sent at all (they'll show as 0/unconfirmed) [Drivechain M6]

Change the number of coins generated per block

Create coins out of thin air

Send coins that never belonged to him [DriveChain M6]

End

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Discussion

jimbocoin 🃏 2y ago

I think that’s what I’m saying, yes. By going through the motions (M3, 13150 M4s, M6), a 51% attacker can spend coins that don’t belong to them (drain the sidechain escrow). This is a new incentive that was not previously present for a 51% attacker on mainchain alone.

Cyber Seagull 2y ago

That's not how a Drivechain softfork would work though. It does not add some new ability to both hack the sidechain and give more power to do a 51% attack than already exists. It uses tools that already exist on bitcoin: merged mining, script contracts, miner fees. Lightning and liquid are both softforks that are as vulnerable to 51% and in the same ways as DC. DC democratizes Liquid and simplifies lightning (BMM no need for a seperate node).

Either these two projects and their vulnerabilites are useful, or they are an existential risk to Bitcoin.

Either Or.

Not

Either Or And Drivechain is bad.

In boolean terms.

jimbocoin 🃏 2y ago

> It does not add some new ability to… hack the sidechain

It does though. The first paragraph of the BIP300 abstract:

> In Bip300, txns are not signed via cryptographic key. Instead, they are "signed" by hashpower, over time. Like a big multisig, 13150-of-26300, where each block is a new "signature".

“Transactions are ‘signed’ by hashpower.” This is a direct quote. Enforcing these hashpower-signed transactions is the reason that BIP300 requires a softfork.

The ability to sign with hashpower is a new ability enabled by BIP300. This new ability is exploitable by a 51% attacker to take sidechain escrow.

Cyber Seagull 2y ago

Within the sidechain. Not main.

Notice the single quotes on either side of that word "signed" ? In the github version they are solid double quotes. Meaning, something like or similar to.

Bip300 does not sign a transaction the way you or several people use your keys to sign a transaction.

It's a vote over time ON THE SIDECHAIN, that some txn is valid. It's like saying changing from single round voting to 3 rounds of voting in a small town election, changes the outcome of national presidential election.

Bip300 ads one new Op code, with sidechain parameters and no mainchain affects for people not participating in it. It does not increase the number of bitcoins, it does not change the turing incompleteness of bitcoin script or break anything on chain.

It's going to happen, if you don't get it at this point i've spent enough time explaining, and wish you the best.

Cyber Seagull 2y ago

I mispoke here, the signing by hashpower is for an on chain transaction, for example pegging out from the side chain to main. But this process is a simple poll vote by miners over time. 51% or more of global hash dominance has no bearing on who gets to vote or how much their vote is valued. The FAQ describes it better.

Cyber Seagull 2y ago

Its getting late

jimbocoin 🃏 2y ago

Take as long as you need

jimbocoin 🃏 2y ago

> But this process is a simple poll vote by miners over time. 51% or more of global hash dominance has no bearing on who gets to vote or how much their vote is valued.

It absolutely does! A 51% miner has the privilege of mining 100% of blocks because they can afford to ignore anyone else’s. Therefore, under BIP300, a 51% miner CASTS ALL VOTES.

Apologies for the emphasis caps, but I want there to be no mistake. In #Bitcoin, a 51% miner doesn’t just mine 51% of blocks. They mine ALL of the blocks.