Any exploit might be interactive with a backend component that generates and serves payload components based on interactive responses.

OP (and anyone else who exploits the server) would be able to see the transcript between the backend and the vulnerable server, containing the payload customised for the server, but not the actual code of the backend. This would be useful if it was a 0day vulnerability, but with a disclosed vulnerability getting a payload that doesn't work except on their server, without the code that generated it, might not be that much value over what they already have.

That said, there are other ways to scam by structuring things like the OP (none of this should be taken to imply the OP has actually done this, but rather why this structure as a general approach might be a bad idea):

* This could be a 'stone soup' scam where the OP has the wallet keys (obviously), and puts this up to bait the addition of more funds into the wallet by other interested people. The key might not actually even be on the server, or it might not be vulnerable. Once sufficient other people add funds, the OP could withdraw the funds, recouping their original funds plus anything others added. * This could be run as a propaganda scam either to falsely sell that it isn't an easily exploitable vulnerability when it is (by making it unreasonably difficult to exploit compared to real-life deployments), or to over-inflate how exploitable it is (by an insider withdrawal from the wallet). Manipulating public opinion could allow an attacker with a working exploit more time, or help to sell services to fix the problem.

I think an alternative scheme that is less vulnerable to scams would be to have a ZKVM (Risc0 or similar) executing vulnerable code, such that the attacker needs to produce a zero knowledge proof transcript of getting the ZKVM into a particular state that would not be possible if they didn't have an exploit. It should also take an Ethereum address as a public input. Then write an Ethereum contract that will allow funds to be transferred to the public input Ethereum address if submitted with a valid proof transcript, and back to the source of funds after some time has passed. Everyone who wants to add to the jackpot could deploy their own version of the contract, so the one proof transcript could claim from all of them, but if unclaimed the funds go back to the source.

Alternatively (avoiding the risk exploits may be so large as to make the cost of producing the proof transcript impractical), they could be built using a public cloud provider's trusted computing offering (e.g. Google Confidential VMs). The person making the challenge could make it so the derivation (NixOS for example) to produce the entire image executing on the cloud provider in a deterministic way (with publicly known source, and hash codes of each stage publicly available). Then, from the code with the known hash, they use the vTPM to generate an attestation that a key was generated while the vTPM PCRs were in a known state (corresponding to the publicly reproducible hashes), and ensure the only way to access the key from the instance is via an exploit. It would also include logic to generate and wrap a Bitcoin wallet key, and emit the public key (with the attestations and a signature linking back via a vTPM attestation to the cloud provider's key). This way, unless the cloud provider is also in on the scam, people could be assured that the OP isn't scamming them.