External Researcher with Questions about RSK

Hello everyone, I am a researcher and I am currently writing a paper on DeFi on Bitcoin. For this, I am looking at all the different solutions out there. Obviously, this include RSK as well. I would have some general questions that I have been grappling with and I’d like to post them here for your to comment and help me. Thank you in advance.

To start off, I am coming at this from a general perspective (that of a user). You usually hear people claim: DeFi solutions on Bitcoin are secured by Bitcoin, the most secure crypto network with the BTC the asset, which is most likely to become the most liquid money.

But what does this even mean “secured by Bitcoin”. In the case of sidechains (I’d call them infrastructure layers on Bitcoin), we can distinguish between the bridging as well as the consensus. I believe that in order for a sidechain to make sense, the needs to be a bullet-proof way for on-chain BTC to appear on the sidechain as a bitcoin derivative that is as good as on-chain BTC because the bridging solution is bullet-proof. So we can look at the security, availability and consistency of the bridging solution to figure this out, right?

Additionally, there is another aspect, which is the sidechain itself. It represents another blockchain, which has its own network with its Bitcoin derivative (or even its own coin altogether). As I understand it, here, the other important point comes into play. How secure is this sidechain and how sure can I be as a user that this sidechain/blockchain is running and that I can use my Bitcoin-derivatives. After all, it does not really help, if I have a very good, bullet-proof bridging solution creating a Bitcoin-derivative that is as good as on-chain BTC but the chain this Bitcoin-derivative is transacted on fails or gets interrupted.

So the question for me is: What sort of attacks can happen when it comes to this aspect: There could be consensus failures or I could be double-spent, or censored. As I understand it, RSK is its own sidechain with its own transaction finality.

So would it be right to say: RSK’s bridging solution is secured by Bitcoin but not necessarily its sidechain (consensus)? Or is this too much black and white as the merge-mining also helps to somehow secure the RSK blockchain?

I would be very glad if you guy can help me get my thoughts sorted so I can arrive at a good understanding of this all.

Thank you!

Hi Pahueg! We have recently published a paper that explains RSK in detail and might answer some of your questions. You can find it here: RSK: A Bitcoin sidechain with stateful smart-contracts

Regarding your question, when we say that RSK is secured by Bitcoin we refer to the merge mining process. For an RSK block to be valid, it must include a Bitcoin block header. This allows Bitcoin miners to produce RSK blocks and claim additional fees in RSK with minimal overhead. At the same time, it also allows the RSK network to benefit from the computational power that Bitcoin miners can provide. So for example, at this precise moment, RSK is being secured by around 50% of Bitcoin’s hashrate.

RSK’s bridging protocol, which is called the Powpeg, is secured by several tamper-proof security devices. You can read more about it in the RSK paper and at the beginning of this medium article.

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