Contributions
- Give general security model for Plasma systems
- Build Plasma with TEE
- analyse the protocl in security model
- Implement on Ethereum and compare it with Plasma, propose extensions
Interesting Points:
- all existing Plasma/commit-chain protocols require periodic commitments to the blockchain and logarithmic size messages to withdraw coins from the system.
- Instead of saying “data sent to blockchain”, one can say: Furthermore, asymptotically the on-chain communication complexity of COMMITEE is O(1), while for all the above mentioned protocols the communication complexity grows logarithmically in the number of users.
Questions
- How to monitor TEE to set up correctly
- users still need to monitor the operator
setences
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These protocols are orchestrated by a so-called operator that maintains the system and processes transactions between parties.
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It is important to note, however, that the operator is not assumed to be trusted, and merely ensures an efficient and well-functioning system.
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The design of such mechanism poses non-trivial challenges that existing Plasma systems attempt to solve by employing either heavy cryptographic machinery such as zero-knowledge proofs or complex challenge-response protocols for resolving disputes on-chain. Neither of these approaches is optimal for the following two reasons: : (1) both approaches significantly increase the communication complexity with the blockcahin which increases costs and undermines the original purpose of Plasma as an off-chain protocol; (2) the security analysis of the resulting protocols becomes cumbersome, and hence to-date there is no Plasma-like system that has been formally proven secure. While there has been significant research efforts to address these problems [9], [8], [21], the community has not yet come up with a suitable solution that can readily be implemented.
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In this section, we provide a brief overview of our solution and discuss its main design challenges that had to be overcome