Using Discreet Log Contracts To Attack Bitcoin Forks

Currently, varied components disincentivize assaults of minority chains; DLCs may create a workaround that returns the inducement to those assaults.

Currently, there are numerous blockchains with miniscule quantities of hash energy in contrast with Bitcoin’s, and but, they hardly ever see assaults. I consider that that is due to exterior components that forestall miners from benefiting from this potential income stream. Discreet Log Contracts (DLCs) are a technique to mitigate these exterior components in order that miners have the flexibility to assault minority blockchains.

The Problem

If one wished to assault a minority blockchain (e.g., BSV), the present finest means could be to steal bitcoin from an alternate. This may very well be finished by depositing some BSV into an alternate, promoting it for bitcoin, withdrawing mentioned bitcoin, after which executing a 51% assault such that the unique BSV deposit by no means occurred. At the top of this, the attacker has acquired Bitcoin with out having to spend any BSV.

There are a number of issues with this assault situation that make it troublesome to execute. One is that the majority exchanges require know-your buyer (KYC) procedures for buying and selling and withdrawals. This signifies that if such an assault have been perpetrated on a blockchain like BSV, the alternate may see precisely who was doing it. Another downside is that the attacker would clearly be stealing from the alternate, which is immoral, and it may destroy a miner/mining pool’s status in the event that they have been to execute such an assault.

Collectively, these components mitigate and arguably take away the incentives that large-scale miners would want to search out such assaults to disrupt minority blockchains worthwhile.


DLCs present a approach to set up contracts on Bitcoin which are contingent on a set of oracles’ attestations. If one wished to assault minority blockchains, it could be helpful to have the ability to guess that they are going to expertise 51% assaults, or to raised quantify such assaults, one may guess {that a} blockchain reorganization (reorg) higher than or equal to 100 blocks will happen. Once a miner has made such a guess, they’ve an financial incentive to assault the minority blockchain, as it could enable them to obtain the payout with out having to steal from an alternate. Such a miner may then assault the blockchain themselves to pressure a 100-block reorg to happen, after which the oracles would attest that the occasion occurred, and the miner may then declare their reward by executing the DLC. Thus, the miner may assault the minority blockchain and receives a commission for it without having to steal from anybody.

The solely factor lacking is that the miners want somebody to fund the opposite aspect of this contract by betting that the minority blockchain will not expertise a big reorg. Anyone may take this guess, whether or not holders of the particular coin or just gamblers. The non-malicious miners of the goal blockchain would have a big incentive to take this aspect of the guess, as they’re the protection system that forestalls these giant reorgs from taking place. In the occasion that the attacker fails, or no assault ever comes, the guess would offer free further revenue for the minority blockchain’s miners.

If a market developed round this, it may create a signalling mechanism that may present when a block reorg assault is about to happen. If a miner have been about to execute a big reorg on a blockchain, they’d possible buy any obtainable contracts betting that the reorg will happen. This mass shopping for of the contracts may sign to the market {that a} reorg is coming, and entities like exchanges may briefly halt deposits and withdrawals to mitigate danger.

In abstract, as we speak Bitcoin miners wouldn’t have a approach to revenue from attacking minority blockchains with out stealing from a regulated entity. DLCs present another that would operate as a market for pricing the price to assault minority blockchains.

This is a visitor publish by Ben Carman. Opinions expressed are fully their very own and don’t essentially replicate these of BTC Inc. or Bitcoin Magazine

The views and opinions expressed herein are the views and opinions of the writer and don’t essentially replicate these of Nasdaq, Inc.

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