Blockchain interoperability actually comes from connecting two or more different chains and validating each other's information. There are various ways to prove it, but among that pegging is one of the most basic and widely used methodology for implementing blockchain-interoperabiltiy.
본래 페그(peg) 또는 페그제(peg system)는 어느 나라의 통화 가치를 특정 국가의 통화에 고정시켜 정해진 환율로 교환하는 것 또는 그러한 고정환율제를 의미한다. 마찬가지로 어느 블록체인의 가치를 다른 블록체인으로 전달하는 것을 페그라 한다.
The definition of Peg, the word itself has been used even before blockchain, is 'A short pin or bolt, typically tapered at one end, that is used for securing something in place, hanging things on, or marking a position.'[1] Following after, the word 'pegged' is used as stable and mostly used in currencies.
But in the blockchain, peg is used among the two or more different blockchains.
There are several ways of pegging way but typically it can be differentiated by 2 ways : One-way peg, Two-way peg. And it's differentiated by the way chains got pegged.
릴레이는 타 블록체인의 **읽기(read)**와 검증을 수행하는 블록체인상에 구현된 시스템이다.[2]
브릿지는 서로 다른 두 블록체인간 상호작용을 수행한다. 브릿지가 릴레이를 포괄하는 개념. paritytech에서는 이더리움 메인넷(mainnet) PoA 사이드체인을 연결하는 Parity Bridge를 개발했다. Parity Bridge는 두 이더리움 기반 블록체인간에 임의의 메시지를 전송할 수 있도록 한다.[4]
Blockstream이 정의한 사이드체인은 "다른 블록체인의 데이터를 검증하는 블록체인"이다. 그러나 일반적으로 사이드체인은 pegged sidechain의 의미로 혼용된다. pegged sidechain은 다른 블록체인의 데이터를 읽어 체인간 교차(cross-chain) 자산 이식성을 용이하게 한다.[5]
위 용어들은 자주 혼용되지만, 본 글에서는 위와같이 정의해 엄밀히 구분한다.
TBA
- issue: memory hard (script) PoW validation의 문제
- 평가
- 방법
- Truebit
- BulletProof <- 추가 조사 필요
- issue: 다른 consensus는 어떻게 구현하나, 검증하나
- 가령 경제학적인 구조에 기반을 둔 consensus
- privacy coin 류 검증은 어떻게 하는가?
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one-way-peg
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two-way-peg
- Symmetric two-way peg
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smart contract를 이용
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collateralized peg
- (가제) centralized-peg
- federate-peg (federated?)
Federate peg is more de-centralized than centralized-peg. Its process is mostly similar with those of multi-signature transaction. As you can see in the term itself, the federation exists in federate-peg. Federation is composed of several different entities and each of them has sort of private keys. They all together mutli-signatuer wallet , which deposit exists.
Federated Peg is a mechanism that uses functionaries to move assets between two chains.[4]
- Hub
For COSMOS Hub is the genesis Zone of its ecosystem. Basically, Hub is connected with all the other zones. Imagine that zone A and B is trying to exchange sort of coins or information. The coin comes out from zone A and go to Hub. Then it goes to zone B. So everytime when two or more than two different zones are trying to interact they have to pass through the Hub.
- multi-sig
For making a transaction, the sender and owner have to use their own keys. Sender has to use their private key to proof the ownership of coins that will be sent and Reciever has to use its public key that will be used as a address. Only the keys of sender and receiver will be used in the transaction. But when it comes Multi-signature transaction some sort of parts will be changed. Most of part is still same, but the signature and ownership part. Ownership of coin or wallet is not belongs to single entity but more than one. And more than certain number of entities who have the ownership must sign to make transaction. M of N multisignature must be signed by at least M entities and the number of entities who have ownership is N.
For example, 3 of 5 multisignature wallet needs at least 3 signs to finish the transaction. And the ownership of wallet belongs to 5 entities. At least 3 signatures are need every single time when transaction occurs.
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add new opcode
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SPV proof
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모든 blocks
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superblock
Superblock first and mostly mentioned at the paper named 'Using Superblocks to Bridge Dogecoin to Ethereum'. The basic concept of Superblock is almost same as that of Merkle hash from Merkle Tree and structure is also almost same with regular block. Superblock act its as the Root hash of several other blocks.
Structure of Superblock that it is proposed will contain :
- The root hash of a Merkle tree built from the block hashes.
- The blocks’ accumulated difficulty.
- The hash of the last block of the superblock.
- The timestamp of the last block of the superblock.
- The hash of the parent superblock data.
Superblock was proposed for being used as a Bridge that connects Dogecoin and Ethereum.
TBA
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프로젝트별?
TBA
[1] https://medium.com/blockchain-musings/pegged-sidechains-cafe1d8c7023
[2] https://medium.com/cryptronics/blockchain-interoperability-moving-assets-across-chains-e5203357d949
[3] https://wiki.polkadot.network/en/latest/polkadot/learn/bridges/
[4] https://github.com/paritytech/parity-bridge
[5] http://blockstream.com/sidechains.pdf