Trustless Bitcoin Bridge Creation with Witness Encryption

Hi, correct me if I am wrong. Assuming the below condition:
Alice deposits 1 BTC to a deposit address generated by the generators and gets the ciphertext CT, and then mints 1 WBTC on the Ethereum chain.
The current Ethereum PoS network is maintained by a group of validators, say it’s group A. And a group named B, is a 2/3 subset of the group A. Say after a year, the group B validators exited the PoS network and withdraw their stake. Then they forked the chain from the checkpoint one year before, thus they wont get slashed even they publish the headers in OP_RETURNs, while they can still burn 1 WBTC to the contract to forge a witness to satisfy the circuit, thus recover the private key with Alice’s ciphertext CT. Does this assumption hold? This a common case for a PoS network according to my understanding.

BTW, is there an implemented PoC version of this brilliant idea? Published somewhere to check? or A plan to implement it?

The ciphertexts get generated when the deposit address is generated. So it already exists before he/she deposits BTC there.

If the BLS signature on a forked chain is published in OP_RETURN, they get slashed.
And even trying that is dangerous for them since only one honest node can reveal that to make them slashed.

The update is here.
It’s not fully inheriting the security assumption, but this is the practical approach that comes after this post.

It was mentioned in the Octopus Contracts post that

“This mechanism primarily enhances the performance of the previous research
result, Trustless Bitcoin Bridge with Witness Encryption (TBBWE) [19], to a
practical level.”

Can I ask how “impractical” is the performance of this design? Is it wait time during withdrawal, computational gas cost, or something else?


New claim of a practical WE scheme

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I’ve forgotten to share this.
The recent hot topic regarding making a trustless bitcoin bridge is BitVM.
Seems you can unlock bitcoin with ZKP.
I’m not 100% sure it works for the bridge, but I truly believe that it’s worth exploring.


tx for sharing; this is very helpful