1.1 关于奇亚

About Chia

什么是奇亚？

奇亚（Chia） 是一个加密货币和区块链智能交易平台。奇亚的设计初衷是让加密货币比现金更容易使用——也更难丢失。奇亚的区块链保持与比特币相同安全级别的同时，只使用一小部分能源。

2017年8月1日，布拉姆·科恩（Bram Cohen）创立奇亚公司并在特拉华州注册成立。布拉姆与许多工程师、研究人员、开源贡献者一起领导了奇亚的开发。在此过程中，奇亚在应用密码学方面创造了三项新发明，并在第四项中提高了兴趣和采用率：

• BLS 签名的首次生产使用。
• 可验证延迟函数（VDF）的首次生产使用。
• 空间证明和时间证明（PoST），这是自工作量证明以来的第一个（也是唯一一个）中本聪（Nakamoto）共识。
• 未知顺序的类组的首次生产使用。

奇亚的主网于 2021 年 3 月 19 日启动。其生态系统的开发正在进行中。

更多公司战略信息请参见奇亚商业白皮书。

原文参考

• What is Chia?

Chia is a cryptocurrency and blockchain smart transaction platform. Chia was designed from the ground up to make cryptocurrency easier to use -- and harder to lose -- than cash. Chia's blockchain maintains the same level of security as Bitcoin's, while using a fraction of the energy.

On August 1, 2017, Bram Cohen founded the Chia company and incorporated it in the state of Delaware. Bram led the development of Chia, along with many engineers, researchers, and open source contributors. Along the way, Chia created three new inventions in applied cryptography, and advanced the interest and adoption in a fourth:

• The first production use of BLS Signatures.
• The first production use of a Verifiable Delay Function (VDF).
• Proofs of Space and Time (PoST), the first (and only) Nakamoto consensus since Proof of Work.
• The first production use of class groups of unknown order.

Chia's mainnet was launched on March 19, 2021. Development of its ecosystem is ongoing.

For more information on the company's strategies, see Chia's business white paper.

奇亚的主要特性

奇亚旨在改进比特币在密码学和数字货币领域的许多开创性思想，同时保持相同的总体目标和理念。奇亚的一些新功能和改进包括：

智能交易

奇亚有一个新的智能交易模型，它使用一个强大（但简单）的高级语言 chialisp，以及一个伴随的低级语言 CLVM (Chialisp 虚拟机）。

奇亚使用硬币集合模型（类似于比特币的 UTXO）来跟踪区块链的状态。该模型的简单性质有助于编写高价值和安全的合同。与使用帐户模型的系统（例如以太坊）不同，创建奇亚代币的代码被严格沙盒化，这提高了安全性，降低了最大可提取价值 (MEV)，并使代码完全可审计。

有关奇亚智能交易的更多信息，请参阅第 4.1 节。

强大的安全性

奇亚币以一种简单却高度安全的方式创建：

coinID = sha256(parent_ID + puzzlehash + amount)

硬币的 ID（sha256 哈希）是存储在区块链上的主要内容。 由于哈希是不可逆的，所以分析区块链的黑客甚至很难确定硬币的类型，更不用说查看创建它的代码了。与以太坊相比，使用反编译器查看智能合约的源代码是微不足道的。

同样由于哈希（的不可逆性），黑客不能在不更改 ID 的情况下更改硬币的谜语 ID、谜语哈希或金额。黑客可以尝试更改硬币的唯一方法是更改它的谜底，确保任何此类更改都将导致花费失败是微不足道的。

更多信息，请参见 chialisp.com。

高效节能

与工作量证明 (PoW) 相比，PoST（时空证明）共识具有更低的能耗，并且奇亚的部分愿景是改善区块链行业的碳足迹。

奇亚的共识算法在第 3 节中有详细讨论。

去中心化

奇亚使用一种称为时空证明的共识算法。该算法允许任何拥有互联网连接和一些可用磁盘空间的人参与保护网络。奇亚独有的农耕程序（类似于挖矿），使其已经拥有数十万个完整节点来保护系统，成为地球上最去中心化的区块链。

升级版矿池

与许多其他区块链一样，奇亚允许小农户汇集以获取平滑收益的奖励结构。但是，奇亚的矿池协议具有三个独特的功能：

• 无论是作为独立个体耕种还是作为矿池的一员，农民都可以创造新的区块。

这个设计决定是结合奇亚的去中心化目标做出的。在比特币等其他区块链中，任何一天都由四个或五个矿池控制着超过全球 51% 的算力。（来源：blockchain.com, blockchair.com) 可以说，攻击比特币最简单的方法是贿赂这些矿池的运营商。

在奇亚中，矿池运营商只负责分配奖励，他们不能修改区块链。因此，奇亚的矿池协议不会导致集中化问题。

• 加入矿池是无需许可的。农民无需注册任何东西即可加入。

• 当赢得一个区块时，农民获得 1/8 的奖励，矿池运营商获得另外的 7/8。这样做是为了阻止当矿池运营商在竞争矿池中耕种，获得证明时却忽略创建区块，从而损害他们的竞争。（作为个体的农民在创建区块时会获得全部奖励。）

有关奇亚矿池协议的更多信息，请参阅第 11 节。

其他主要特性

这里还有奇亚的许多其他创新点，其中一些包括：

• BLS 签名，允许将一个区块的所有签名聚合在一起。
• 可扩展性和性能改进，允许在树莓派上运行奇亚节点。
• 权重证明和轻量客户端，可从移动设备快速同步。更多详细信息，请参阅第 3.12 节。

本文档将向技术受众解释奇亚系统不同组件的动机和实现，并提供一切工作原理的深入解释。如果你想跳到如何在奇亚上制作去中心化应用程序（dapps），请访问 chialisp.com。

原文参考

• Chia's key features

Chia aims to improve upon Bitcoin's many pioneering ideas in the fields of cryptography and digital currencies, while maintaining the same overall purpose and philosophy. Some of Chia's new features and improvements include:

• Smart transactions

Chia has a new smart transaction model, which uses a powerful (yet simple) higher-level language called chialisp, and an accompanying lower-level language called CLVM (ChiaLisp Virtual Machine).

Chia uses the coin set model (similar to Bitcoin's UTXO) to track the blockchain's state. The simple nature of this model facilitates the writing of high value and secure contracts. Unlike in systems that use the account model such as Ethereum, the code that creates Chia's coins is strongly sandboxed. This increases security, reduces Maximum Extractable Value (MEV), and makes the code fully auditable.

For more info on Chia's smart transactions, see Section 4.1.

• Strong Security

Chia's coins are created in a simple, yet highly secure manner:

coinID = sha256(parent_ID + puzzlehash + amount)

The coin's ID (a sha256 hash) is the main aspect that's stored on the blockchain. Hashes are not reversible, so it's very difficult for a hacker analyzing the blockchain to even determine what a coin's type is, let alone to view the code that created it. Contrast that with Ethereum, where it's trivial to view a smart contract's source code by using a decompiler.

Also due to hashing, a hacker cannot change a coin's parent_ID, puzzlehash, or amount without changing the ID as well. The only aspect of a coin that a hacker can attempt to change is its solution, and it's trivial to ensure that any such changes will result in a failure to spend the coin.

For more info, see chialisp.com.

• Energy efficient

The PoST consensus has a much lower energy consumption compared to Proof of Work (PoW), and part of Chia's vision involves improving the carbon footprint of the blockchain industry.

Chia's consensus algorithm is discussed in detail in Section 3.

• Decentralized

Chia uses a consensus algorithm called Proofs of Space and Time. This algorithm allows anyone with an internet connection and some free disk space to participate in securing the network. Because of this process of farming (analogous to mining), Chia has become the most decentralized blockchain on the planet, with hundreds of thousands of full nodes securing the system.

• Improved Pooling

Like many other blockchains, Chia allows pooling to smooth out the rewards structure for smaller farmers. However, Chia's pooling protocol has three unique features:

• Farmers create new blocks, whether they're farming solo or as a member of a pool.

  This design decision was made in conjunction with Chia's goal of decentralization. In other blockchains such as Bitcoin, four or five pools control over 51% of the global hashrate on any given day. (Sources: blockchain.com, blockchair.com) Arguably, the easiest way to attack Bitcoin would be to bribe each of these pools' operators.

  In Chia, the pool operators are only responsible for distributing rewards. They cannot modify the blockchain. Therefore, Chia's pooling protocol doesn't lead to increased centralization.

• Joining a pool is permissionless. Farmers don't need to sign up for anything in order to join.

• When a block is won, the farmer gets 1/8 of the rewards, and the pool operator gets the other 7/8. This was done to discourage pool operators from harming their competition by farming on a competing pool and neglecting to create a block when they find a proof. (Solo farmers collect the entire reward when they create a block.)

For more info on Chia's pooling protocol, see Section 11.

• Other key features

There are many other innovations in Chia, some of which include:

• BLS signatures, which allow aggregating all of a block's signatures together.
• Scalability and performance improvements, which allow running a Chia node on a Raspberry Pi.
• Weight proofs and light clients, which enable fast syncing from a mobile device. For more info, see Section 3.12 .

This documentation will explain the motivation and implementation of the different components of the Chia system to a technical audience, and provide in-depth explanations of how everything works. If you would like to skip to how to make dapps (decentralized apps) on Chia, please visit chialisp.com.