WBTC 介紹
由於 ERC20 Token 的易用與普遍性，ERC20 代幣成為重要的數位資產表示方式，並同時繼承來自區塊鏈與以太坊的優點，更佳的透明度與較快的交易時間。如果能將某個資產，打包成 ERC20 Token，某種程度像是在以太鏈上發行穩定貨幣，這裡的穩定貨幣意義不一定是指代幣與法幣價格上的 1:1，也可指數量上的 1:1，例如 1 BTC=1 ERC20 BTC Token。
選單
由於 ERC20 Token 的易用與普遍性，ERC20 代幣成為重要的數位資產表示方式，並同時繼承來自區塊鏈與以太坊的優點，更佳的透明度與較快的交易時間。如果能將某個資產，打包成 ERC20 Token，某種程度像是在以太鏈上發行穩定貨幣，這裡的穩定貨幣意義不一定是指代幣與法幣價格上的 1:1，也可指數量上的 1:1，例如 1 BTC=1 ERC20 BTC Token。
BIP141 就提議，在 block 裡面創造一個新的資料結構叫 witness program 來存放 transaction 的 input script。如此一來會把簽名的部分分離 (segregate) 出 transaction 了，所以才叫做 segregated witness，簡稱 segwit。
Key management plays a significant role in blockchain technology regarding digital assets protection. Practically speaking, losing private keys leads to great losses. Improper key management and poor system implementation may increase the risk of asset being transferred maliciously. Take an extreme case that happened before as an example, a principal died suddenly and no one was able to recover keys so that the whole asset was frozen. To solve these problems, experts therefore propose threshold cryptography to reduce the risk of key management.
在前面的文章中，我們介紹過 LibraSwap，但實際上透過 Libra SPV，我們可用於搭建 Libra 與 Ethereum 之間的橋樑，稱做 LibraBridge。利用 SPV validation 實作跨鏈的代幣交換不是新的創舉，過去有許多項目利用這個方法來橋接兩個不同的鏈上資產，如下。SPV 是一種用於輕節點驗證交易的方法，透過智能合約的協助，我們可以在合約上驗證來自 Libra 的交易。
In the previous article, we explain the concept of the LibraSwap. Next, we will introduce LibraBridge, which can be used to connect Libra with Ethereum by Libra SPV method. The idea to leverage SPV validation to implement cross-chain transfer is not new. It’s already done by several projects listed below. SPV proof is a way for light client to verify if interested transaction happened on the blockchain. With the help of smart contract, Libra SPV proof can be implemented on Ethereum. Namely, we can verify a Libra transaction through smart contract, along with some external information.
Generally, you need to have a client when connecting to the blockchain network. There are different types of nodes: full node, light node, mining node and relay node. In this article, we will focus on how a light client node works because not everyone can run a validator node (full node) in Libra since it is a permissioned blockchain. Instead of fully verifying all transactions and blocks, light clients only need to download block headers and verify if interested transactions are included in the block. Light clients are run by devices that do not have huge computation power and bandwidth.
On June 18, Facebook unveiled its blockchain project, called Libra. The goal of Libra is to build a new financial infrastructure that empowers billions of people to access financial service efficiently and cheaply. According to the white paper, Libra is expected to launch in 2020. However, the emergence of Libra makes the US Congress ask Facebook to pause its development because the new global currency it brings would harm existing financial system. Libra published the white paper, open sourced the projects, and release the Testnet. Thus, developers can play around with the Libra and contribute to Libra Core. Currently, the Libra project is under ongoing development and the discussion forum is active too.
今年六月，臉書宣布其區塊鏈計畫 — Libra，旨在打造一個普惠金融 (Inclusive Financing) 的支付系統。按臉書原先的計畫，預計會在 2020 正式上線，雖然美國國會要求臉書暫緩 Libra 專案，除此之外，臉書也發佈了 Libra 白皮書，並且開源 Libra 原始碼以及測試鏈，讓開發者可以先嘗鮮。截至目前，Libra 的開源項目仍在持續開發，程式碼不停在更新，討論區也是相當活躍。
