Dai Wei，也许他的中文名是 “戴伟”。 他是华人，也是密码朋克小组中，我们所知道的唯一华人。在比特币之前，他提出的 B-Money 概念，实际上就是比特币的原型。而中本聪与其沟通的三封邮件中，明确指出自己发明的比特币 “实现了戴伟的 B-Money 概念”。
第一封邮件：中本聪至 Dai Wei
From: "Satoshi Nakamoto"
Sent: Friday, August 22, 2008 4:38 PM
To: "Wei Dai"
Cc: "Satoshi Nakamoto"
Subject: Citation of your b-money pageI was very interested to read your b-money page. I'm getting ready to release a paper that expands on your ideas into a complete working system. Adam Back (hashcash.org) noticed the similarities and pointed me to your site.
I need to find out the year of publication of your b-money page for the citation in my paper. It'll look like: [1] W. Dai, "b-money," http://www.weidai.com/bmoney.txt, (2006?).
You can download a pre-release draft at http://www.upload.ae/file/6157/ecash-pdf.html Feel free to forward it to anyone else you think would be interested.
Title: Electronic Cash Without a Trusted Third Party
Abstract: A purely peer-to-peer version of electronic cash would allow online payments to be sent directly from one party to another without the burdens of going through a financial institution. Digital signatures offer part of the solution, but the main benefits are lost if a trusted party is still required to prevent double-spending. We propose a solution to the double-spending problem using a peer-to-peer network. The network timestamps transactions by hashing them into an ongoing chain of hash-based proof-of-work, forming a record that cannot be changed without redoing the proof-of-work. The longest chain not only serves as proof of the sequence of events witnessed, but proof that it came from the largest pool of CPU power. As long as honest nodes control the most CPU power on the network, they can generate the longest chain and outpace any attackers. The network itself requires minimal structure. Messages are broadcasted on a best effort basis, and nodes can leave and rejoin the network at will, accepting the longest proof-of-work chain as proof of what happened while they were gone.
Satoshi
中本聪给 Dai Wei 邮件的译文：
我读了您介绍 b-money 的网页，非常感兴趣。 我很快就会发出一篇论文，能把您的思路，扩展成一个完整的，可运行的系统。 是 Adam Back (hashcash.org) 发现了两者之间的相似之处，也是他让我来看您的网站。
为了在我的论文中引用您的 b-money 概念，我需要确认您的 b-money 网页的发布日期。 我的引用会是这样：[1] W. Dai, "b-money," http://www.weidai.com/bmoney.txt, (2006?).
您从 http://www.upload.ae/file/6157/ecash-pdf.html 这个地址可以下载一份论文初稿。如果您觉得有人会感兴趣，也请转发。
标题：无需可信第三方的电子货币
摘要：一个彻底实现点对点的电子货币系统，可以在网络上从一方直接支付到另一方，完全无需依赖金融机构。电子签名解决了部分问题，但如果为了防备 “双花”问题，依然还需要引入一个可信第三方的话，那就失去了点对点的主要优势。我们设计了一个方案，在点对点网络中，可以解决 “双花” 问题。在此网络上，通过对交易进行哈希运算，为交易打上时间戳，并勾连成链，且以哈希运算来证明创建链的工作量。这样就形成了一条记录，该记录是无法篡改的，除非重算所有工作量证明。最长的链，不仅见证了事件发生的顺序，也代表了它来自最大的 CPU 算力池。只要诚实的节点控制了网络中大部分的 CPU 算力，则它们就能够生成最长的链条，并把攻击者抛在后面。此网络本身只需要最小的结构 。消息以最佳的效果传播，节点可以随意离开，也可以随意重新加入网络，加入时接受工作量证明最长的链，认可那是它们离开网络期间所发生事件的见证。
中本聪
第二封邮件：Dai Wei 至中本聪
Hi Satoshi. b-money was announced on the cypherpunks mailing list in 1998.
Here's the archived post:
http://cypherpunks.venona.com/date/1998/11/msg00941.htmlThere are some discussions of it at http://cypherpunks.venona.com/date/1998/12/msg00194.html.
Thanks for letting me know about your paper. I'll take a look at it and let you know if I have any comments or questions.
Dai Wei 给中本聪邮件的译文：
Hi 中本聪：
b-money 是 1998 年在密码朋克邮件组中发表的。
下面是归档的帖子:
http://cypherpunks.venona.com/date/1998/11/msg00941.html
这里您还能找到一些关于 b-money 的讨论：
http://cypherpunks.venona.com/date/1998/12/msg00194.html.
谢谢告知您的论文。我会读一下，如果我有意见和问题，我会联系您。
第三封邮件：中本聪至 Dai Wei
From: Satoshi Nakamoto
Sent: Saturday, January 10, 2009 11:17 AM
To: weidai@weidai.comSubject: Re: Citation of your b-money page
I wanted to let you know, I just released the full implementation of the paper I sent you a few months ago, Bitcoin v0.1. Details, download and screenshots are at www.bitcoin.org I think it achieves nearly all the goals you set out to solve in your
b-money paper.
The system is entirely decentralized, without any server or trusted parties. The network infrastructure can support a full range of escrow transactions and contracts, but for now the focus is on the basics of money and transactions.
There was a discussion of the design on the Cryptography mailing list.
Hal Finney gave a good high-level overview:
| One thing I might mention is that in many ways bitcoin is two independent
| ideas: a way of solving the kinds of problems James lists here, of
| creating a globally consistent but decentralized database; and then using
| it for a system similar to Wei Dai's b-money (which is referenced in the
| paper) but transaction/coin based rather than account based. Solving the
| global, massively decentralized database problem is arguably the harder
| part, as James emphasizes. The use of proof-of-work as a tool for this
| purpose is a novel idea well worth further review IMO.Satoshi
中本聪给 Dai Wei 邮件的译文：
From: Satoshi Nakamoto
Sent: Saturday, January 10, 2009 11:17 AM
To: weidai@weidai.com
Subject: Re: Citation of your b-money page我特为告知您，我刚刚发布了比特币 v0.1 版，这个系统完全实现了几个月前我发给您的论文中的思想。从 www.bitcoin.org 您可以获得详细信息，也可以下载软件和屏幕截图。
我想，您在 b-money 论文中想要解决的问题，比特币几乎都做到了。
系统完全是去中心化的，无需任何服务器，也无需任何可信方。此网络的架构，能够支持各种托管交易和合约类型，但当前还只是实现了货币和交易的功能。
在密码学邮件组中，有一个围绕设计的讨论。
哈尔芬尼作出的一个概括评价，非常好：“我想提的一点是，比特币从各种角度看，都是两个独立的创意：首先是解决了 James 列出的那些问题，创造出一个实现了全局一致，但又去中心化的数据库；然后用来实现了与 Wei Dai 的 b-money 非常类似的系统，但却又不是基于账户的，而是基于交易/现金的。 James 就曾强调过，实现全局一致，但又大规模的去中心化数据库，毫无疑问是最困难的部分。利用工作量证明的方法，来解决这个问题，是个天才的主意，非常值得进一步的认真思考。”
中本聪
