2018-06-12

Vitalik 认为以太坊在2018年得着重提高扩展性

去年以太坊的市值暴增，但是 Vitalik 并不觉得以太坊做了足够的事情匹配这个价格

So total cryptocoin market cap just hit $0.5T today. But have we earned it?

• How many dapps have we created that have substantial usage?
• How much value is stored in smart contracts that actually do anything interesting?
• How much actual usage of micropayment channels is there actually in reality?

The answer to all of these questions is definitely not zero, and in some cases it's quite significant. But not enough to say it's $0.5T levels of significant. Not enough.
2017/12/12 https://twitter.com/VitalikButerin/status/940744724431982594

If all that we accomplish is lambo memes and immature puns about "sharting", then I WILL leave.
2017/12/27 https://twitter.com/VitalikButerin/status/945988644661207040

并计划2018年主要精力放在提高扩展性(Plasma, POS)、隐私性(ZK-STARKs)

I expect 2018, at least within the Ethereum space that I’m best able to speak about, will be the year of action. It will be the year where all of the ideas around scalability, Plasma, proof-of-stake, and privacy that we have painstakingly worked on and refined over the last four years are finally going to turn into real, live working code that you can play around in a highly mature form in some cases on testnets, and in some key cases even on the public mainnet.
~ 2018/01 Vitalik
https://techcrunch.com/2018/01/15/vitalik-buterin-fenbushi-capital-exit/

提高拓展性的5种方法中，他觉得 channels/plasma 和 sharding 是最有效的方法。

My view: there are basically 5 scaling strategies:

1. Many separate chains
2. Super-big blocks
3. Incremental improvements that don't change security model (eg. replacing txs + sigs with compressed delta + STARKs)
4. Layer 2 (channels and plasma)
5. Sharding

2018/06/09 https://twitter.com/VitalikButerin/status/1005384496311496704

(1) and (2) are obviously useful to some extent but ultimately insufficient and kinda lame (for scaling that is; obviously we need many separate chains for experimentation and ecosystem diversity). (3) is arguably underrated. (4) and (5) can give the biggest gains.

2018/06/09 https://twitter.com/VitalikButerin/status/1005385470912561153

ZK-STARKs

零知识证明 Zero knowledge(ZK) proof 是种加密技术，可以在不用告诉对方具体信息的条件下，让对方知道自己知道一样东西。比如有一个数独题，在解出答案之后，如何在不告诉对方答案的情况下，让对方可以确信我解出来了。

这个加密技术可以用于提高隐私性。
现有的比特币的数据是公开的，虽然别人无法知道每个公钥的所有者是谁，但是如果线下交易的话，别人就可以把公钥和具体的人对应起来，然后查到你当前的余额，找到你之前的所有交易记录。

自从 1990s 提出 ZK 系统以来，它的验证效率并不高，不能满足大量数据的需要。

Transparent ZK proofs that can be verified exponentially faster than data size were first described in the 1990s but early constructions were impractical, and no ZK system realized thus far in code (including that used by crypto-currencies like ZcashTM) has achieved both transparency and exponential verification speedup, simultaneously, for general computations.
2018/03/06 Ben-Sasson, Eli, et al. "Scalable, transparent, and post-quantum secure computational integrity."

Zcash 使用高效的 ZK-STARKs，但是透明度不高

以色列科学家 Eli Ben-Sasson 试图解决这个问题，
在 2017/06 的一次演讲中提出
https://people.eecs.berkeley.edu/~alexch/docs/pcpip_bensasson.pdf
并在 2018/03/06 创作白皮书
https://eprint.iacr.org/2018/046.pdf

侧链的发展进程

• 2014/10 Adam Back 提出 sidechain

• 2014/12 提出 hub-and-spoke micropayments

• 2015/10 Joseph Poon 提出 lightning network

• 2015/10 Jeff Coleman 在博客中提出 state channel

• 2016/10 Gavin Wood 提出 Polkadot

• 2017/08 Joseph Poon 提出 Plasma

• 2017/10 Jason Teutsch 提出 Truebit

交易所被盗导致比特币价格大跌

2018/06/09 韩国的数字货币交易所 Coinrail 被盗，1/3 的钱都丢了，损失大约 $3700万，包括 NPXS, ATX, NPER, DENT 币。随后比特币价格连续两天暴跌。

The value of bitcoin and many other digital currencies fell to their lowest levels this year after South Korean exchange Coinrail said a hack over the weekend stole virtual coin estimated to be worth more than $37 million.
2018/06/12 https://arstechnica.com/information-technology/2018/06/bitcoin-prices-continue-to-fall-as-yet-another-exchange-reports-a-breach/

转账记录

黑客的钱包地址: https://etherscan.io/address/0xdf9191889649c442836ef55de5036a7b694115b6#tokentxns

比特币为什么没有流行起来

Nobody actually wants to pay with bitcoin, which is why it hasn’t taken off.
2017/12/23 https://hackernoon.com/ten-years-in-nobody-has-come-up-with-a-use-case-for-blockchain-ee98c180100?source=linkShare-a923f4aff9ba-1528788905

之所以比特币没有风行起来，当然是因为人们还不喜欢用它。其背后我认为主要是这几个原因：

1. 价格波动太大
2. 交易速度太慢
3. 手续费对于小额支付不划算

但随着侧链技术的成熟，#2 #3 问题可能会得到很好的解决，从而实用性更强，从而使用人数增多，比特币越来越受到认可，价格波动会下降， #1 问题也会得到解决。