🌻另一個Zoom會議(第二次貼......有補上一些內容)
繼上次的年報導讀會議後, 讓我們再做另一個會議! 這次很榮幸邀請到一位對估值很有見解的股友前輩來帶大家了解估值(恩, 這次我會是主持人, 不是主講人).
主題: 估值(valuation)分享會(Cat: 這不算基礎的估值會議)
主講人: 小揚(from安泰價值投資)
https://www.facebook.com/antaiinvestment　(此為小揚的粉絲頁)
參與者: 具基本估值能力. 若打算參加者, 請事先跟我(請私訊)提出一個關於估值的case study, 到時候可在會議中分享(最好是以投影片形式呈現, 這樣到時候好跟大家分享). 若有估值的問題, 也可以提出.
Case study可以是美股, 也可以是台股.
時間: 台灣時間07/10 (周六)晚間９點.
預計一個小時(不會像上次那樣冗長了😅): 前30分鐘由小揚做分享, 後30分鐘大家分享估值案例&提問
進行方式: 以Zoom進行(之後會私訊會議資訊給參與者)

🌻Morgan Stanley Mid-year Investor Outlook: A tricky transition

https://www.morganstanley.com/ideas/midyear-2021-global-markets-outlook

🌻在您投資生涯中, 有沒有一些觀念讓您受用很多?
下面這位投資名人的好觀念影響我很深. 他的意思是, 一般投資人, 只要能説出三個買一家公司的理由, 就很夠了. 這也迫使我, 每次在買股票時, 問自己對這家公司的了解有多少. 也會去衡量公司的優點與缺點在哪裡.

"It is vital (重要的) that you know what you own, that if I asked you on the street why you like a certain stock, you can give me three reasons. If you don't know how they make their money, who their key clients are and what they make if, then I will tell you that you are over your head and should not own individual stocks."

全文在此:
Jim Cramer: In Times Like This, Go for the Easy Money
Look at the stocks you own. Can you tell me why you've got them? If you can't answer the following three questions, then have a look at several I like right now.

We've endured the meme stock craziness, with all of its love for heavily shorted stocks. We have watched the collapse of bitcoin to levels viewed as shocking, even if they are still more than double where they were not that long ago. We've dealt with Fed officials making it clear that they are no longer on the side of the bulls or the bears. They are on the side of job growth, but are wary of inflation. We've seen the end of the rush to get vaccines, which means that millions of people are going to get the new COVID variant, because there is no natural immunity to it. We've watched as the hopes for an infrastructure bill have collapsed. We've endured shortages of everything from chips to plastic to imported goods and labor.

And we're still standing, yeah, yeah, yeah.

Yep, we are in one of those halcyon moments, where the masks are off -- even if they shouldn't be -- and Americans are back doing what they do best: consume, spend, go out to eat and then consume and spend some more.

There are times in the stock market where the collective mindset is revealed. This is one of those times: Things are cool, it's not a big moment, there's no real news for a bit, it's the historically strong period and we can reach some conclusions about where we are.

When things are like this, it is important to remember that buyers like to revert to tried-and-true companies that thrive no matter what. These are companies that have an edge and are better at what they do than other companies.

You know that I am a great believer in index funds, that the average person doesn't have the time or the inclination to research individual stocks. It's a difficult barrier. I think you need to make time to read the quarterly report and listen to the conference call, to Google articles and, if possible, get some research about the companies you own. It is vital that you know what you own, that if I asked you on the street why you like a certain stock, you can give me three reasons. If you don't know how they make their money, who their key clients are and what they make if, then I will tell you that you are over your head and should not own individual stocks. I am reminded by this, because, once again, without a mask, I can be recognized and if I am not holding "Nvidia the Second," I can carry on a conversation.

I have had many in the last two weeks and when I have asked this litany of questions, I find myself at a loss as to why almost no one knew what they owned. But they thirsted for individual stocks, because they, like me, think things are better post pandemic. No, that's not a facetious comment. Many, many stocks did better with a stay-at-home economy. A huge number.

So what do I do? I revert to what others do when you are stumped about how to stay in touch with stocks, but want to do less homework. That means buying stocks that are accessible, not stocks like Unity (U) or Snowflake (SNOW) or Twilio (TWLO) or Okta (OKTA) .

I revert to normal businesses people know and I suggest they Google some articles, peruse the conference call, but, above all, like the company's products so you can buy more if it goes down.

Here's some that I have been telling people I like:

First is Ford (F) . I think the Ford lineup is amazing. The electric F-150 series will be incredible. I am eager to get a Maverick for my family, because it is a smaller pickup that will get the job done for the myriad little things I need to do with this farm I bought from that crazy bitcoin foray. I like the competitive edge of the CEO, who says he is going to bury Elon Musk when the Lightning comes out. I even think the Bronco is cool as all get out. Most important, though? I think the chip shortage is ending. My semiconductor friends are telling me the foundries are producing more feature-rich chips and that means Ford can pump out the trucks small business people love and need. Plus, the used car prices at last have plateaued, according to their most important pricing index. Halcyon times.

Second, Costco (COST) : The samples are coming back. Tell me you don't love the samples. You need things in bulk. You want low prices. You want to get all of the things that people don't think of with Costco, like insurance, hearing-aids -- hey, they are a fortune -- jewelry, things around the house. You go and you will buy far more than you first came for. My kind of store.

The kids love this American Eagle Outfitters (AEO) , which we just bought for my charitable trust, which you can follow along by joining the Action Alerts PLUS club. Jay Schottenstein, the CEO, came on "Mad Money" recently and it's clear that his Aerie model has real staying power: 26 consecutive quarters of double digit growth. No flash in the pan, that one. Number one brand in jeans for the 15 to 25 year old group. The best in the mall. How did I know this? I see the credit card bills.

I got up this morning to do my physical therapy. I have been doing it ever since I hurt my back in February. I have this really cool pair of sneakers that fit me perfectly and I love them, but I am fortunate enough to have a vacation house and I am always taking those shoes with me.

So I went on Amazon (AMZN) this morning and lo and behold I saw them for half price. I bought two pairs. Then I went over everything I have bought in the last year and got a bunch of those things. Then I bought a pair of binoculars, because mine were stolen. I paid half price.

Yep, Amazon's universal. I was talking to Alexa, while I was ordering, getting some new music on, asking questions. I saw that despite all of the Sturm und Drang of Amazon being late with things, all the delivery dates were within range. I didn't click on any ads, and I didn't need the speed of Web Services, but the whole thing reminded me about how special the darned company is. I don't care if it's ahead or behind plan for the moment. I would just buy some more when it goes down.

Finally, Apple (AAPL) . I think people who don't own Apple should look what they are holding at this very moment. Yes, right now. Or look at what's in your lap or on the table besides your fork. And then think about the bill you paid last night without knowing it. Think about what you bought in the App store yesterday. Think about what would happen if it would break or get stolen or, left in the Uber (UBER) , or heaven forbid, be dropped into the pool or in the, yes, toilet.

There, that's what you buy in halcyon times. Stocks of companies you know that if they go lower, because things get less halcyon, you are fine with it and buy more. If things go up, believe me, you will participate.

So accept the moment. Don't try for the hard money. Go for the easy kind. That's the best kind.

https://realmoney.thestreet.com/jim-cramer/jim-cramer--15692051

Picture: 牡丹(peony)花開. 恨不得院子裡有一塊地是牡丹園.

📜 [專欄新文章] EIP-1014 產生可控的智能合約地址

✍️ 飛天的狸貓

📥 歡迎投稿： https://medium.com/taipei-ethereum-meetup #徵技術分享文 #使用心得 #教學文 #medium

先前在 Solidity Taiwan 讀書會 群中看到一個討論，裡面應該是一個套利機器人，打開他的合約會發現 Contract 標記著 Reinit，大致上意思是在相同地址上曾經 Self Destruct 後又佈署新的 Byte Code。這其中就用到了 Vitalik 提出的 EIP-1014，來達成在固定的地址上佈署。

合約地址是怎麼產生的

如果對於以太坊智能合約佈署不陌生，應該會知道合約地址是依據佈署者的地址和他的 Nonce 來決定的。假如地址 0xa1 在 Nonce 為 1 的交易中建立了合約，合約地址是 0x01，則當他到了其他鏈而再次使用 Nonce 1 建立合約時，就也會得到相同的合約地址 0x01。

而在以太坊中，Nonce 是嚴格遞增的，這主要是為了避免雙花攻擊，因此很顯然的，再次佈署到同一個地址是不可行的。而在 EIP-1014 以前，在合約中建立的子合約也是透過這個方式達成。

EIP-1014 做了什麼

前面說到合約中可以建立子合約，通常使用的指令是 create，這個指令便會根據主合約的地址與合約本身的 Nonce 來算出子合約的地址。在 EIP-1014 中，提出了另外一個指令 create2，接受的參數是一個 salt 和 init code（建立合約的 Byte Code）。這個指令會透過 keccak256 雜湊，混和參數和主合約的地址來算出子合約地址。

可以留意到，salt 和 init code 都是可控的，主合約地址是固定的，因此就讓子合約地址是可控制的（當然不是說想要產生在哪裡就在哪裡）。在 create 中，Nonce 是漸次增加的，所以無法重複，並且若要控制到特定 Nonce 需要發起多筆交易。

但是當再次佈署到相同地址時，EIP-684 說明若該地址 Nonce 不為零或者存在 Byte Code 時將直接拋出錯誤，因此若要佈署到同一個位置，就必須利用 Self Destruct 來抹去 Nonce 和 Byte Code。

為什麼要 EIP-1014

EIP-1014 在起初是基於 State Channel 的需求，主要是因為某些狀況下可能還沒有要和合約做互動，但需要先知道合約地址。因此只要是需要先知道地址，但沒有要立即使用的合約就十分適合通過這個指令來建立。

例如對於交易所來說，替所有要入金的人建立私鑰有管理上的問題，若透過智能合約則相對有彈性，但卻不是所有申請地址的人都真的會入金，此時就適合利用這個指令先行取得地址，當真的有入金時再佈署合約。

如何使用 EIP-1014

除了直接寫 Opcode 以外，Solidity 0.6.2 加入了利用 create2 建立合約的語法。使用方式是 new Contract{salt: someByte}(...args)，其中 new Contract(...args) 就是傳統的佈署方式，而 someByte 是一個 bytes32。

資安疑慮

回到開頭，Etherscan 之所以會標記 Reinit 則是因為可能有資安的疑慮。回顧地址產生的過程，兩個參數都沒有限制條件，因此碰撞的可能也是存在的。如果不肖人士先佈署一個正常的合約，接著通過 Self Destruct 刪除後再佈署假的合約，就可能讓沒注意到的使用者上當。

但或許因為碰撞的機會太低，所以並不太構成問題。而若真的要從使用者的角度防範，可以通過檢查合約有沒有 Self Destruct、Delegate Call、Call Code 指令（如果沒有的話無法刪除合約，再次 create2 時就會被 revert）來避免。

2021/4/23 補充

後來看了幾個討論，也想了一下，資安的疑慮應該遠不只上面這麼簡單。
例如一個宣稱鎖定 ERC-20 代幣的合約，雖然使用者可以檢閱程式碼，並確認其中解鎖 function unlock() 必須在 uint256 block 之後才能執行，並且 block 是無法變更的，但攻擊者可能透過上述方法來消除 block 狀態，進而提前執行 unlock。

參考資料

https://consensys.net/diligence/blog/2019/02/smart-contract-security-newsletter-16-create2-faq/

https://www.chainnews.com/zh-hant/articles/803272341363.htm

如有錯誤敬請指正，原文載於：https://limaois.me/archives/265

EIP-1014 產生可控的智能合約地址 was originally published in Taipei Ethereum Meetup on Medium, where people are continuing the conversation by highlighting and responding to this story.

👏 歡迎轉載分享鼓掌

« 寫給馬戲團的朋友»
Writing To My Friends In The Circus (English version below)

馬戲團的朋友，實在是多到無法數。她他們當中有專士、碩士、大學生、醫生、護士、教師，和來自地產界、銀行界、飲食、服務業、科技業......等等。她他們當中當然也有可愛的、可惡的，以及......，哎呀！總而言之，就是一種米養百種人囉！不好意思，不好意思，近日接見了一對「搶錢夫妻」，都是高學歷者，不懂為什麼，講話常有囉字參雜其中，是女的不是男的。吾馬上就恢復純正的華語，真的不信也不行，近朱者赤，近墨者黑啊！

馬戲團的朋友們時不時都有想要向吾，討教如何改善自身命運的方法，如玄學及佛法。基於如此有福氣的想法，玳瑚師父當然是歡迎，且當仁不讓的。祇不過，吾希望所有欲學玄學及佛法者，務必要認真思考妳你們的出發心，不可暗室欺心地想或以為，神不知鬼不覺啊！學佛學玄學，同樣都是利己利她他，冥陽兩利的，絕不可為了自己的私慾，而跑去皈依，然後騙師父說，是她他人硬拉妳你去皈依的。再說，師父老早就知道，妳你在馬戲團裡的角色，事先已清清楚楚，向妳你解說這方面的因果與戒律，妳你還是要往刀山火海去，吾就祇好唸佛，願妳你速醒，速懺悔，以免為時已晚。

「搶錢夫妻」中的妻子，皈依近三十年，竟然對佛教基本戒律及禮儀，毫不遵守且任意妄為，叫吾這玳瑚師父唯懮無喜，世人要明白，菩薩畏因，眾生畏果啊！今天吾，玳瑚師父，傳妳你們口訣:

世事本無愁，
不平本來有;
無心不起貪，
一切又何愁。

馬戲團的朋友們，一直都認為，觀眾皆喜看「高難度的表演」，那是因為她他們祇是「觀眾」，而吾並不是。吾是真心給於妳你們的朋友，妳你們常「表演的高難度」，唯吾一直身體力行地，賦於妳你們協助與加持。

--------------------------

I have countless friends in the Circus. Among them are specialists, post graduates, graduates, doctors, nurses, teachers, as well as professionals from the real estate, banking, food and beverages, fashion, technology industries, etc. Some of them are adorable, some of them are not so pleasant, while some of them are.... aiya! In a nutshell, as the Chinese saying goes, the same type of rice feeds a hundred types of people. It takes all sorts to make a world lor! My apologies, I recently met a "money-grabbing" couple who are highly educated people but I am not sure why the lady kept sprouting "lor" in her sentences. Let me revert back to the proper language usage. No wonder the Chinese saying goes, "One who mixes with vermilion will be stained red, one who gets near ink will be stained black."

My friends in the Circus would seek my advice, from time to time, on ways to improve their lot, thorough the Dharma and Chinese Metaphysics. Of course, I welcome people blessed with such thinking, and no way will I shirk away from my obligations. However, I urge all of you who wish to learn more about the Chinese Metaphysics and the Dharma, to give serious consideration about your intention to do so. Do not deceive yourself and assume that the Gods and the ghosts will not know your motives. To learn the Dharma and Chinese Metaphysics is to bring benefits to others and yourself, to benefit both the living and dead. It is definitely not for your own selfish gain. You must not run to take refuge in the Three Jewels for your personal egocentric agenda, and then lie to me that you were dragged along to do so by other people. Master Dai Hu already knows your role in the Circus and has clearly explained to you the cause and effect involved, and the precepts. If you still choose to throw yourself into the sea of fire, and up the mountain of daggers, I can only recite the Buddha's name and pray that you will wake up from your folly and repent sincerely before it becomes too late.

Despite taking refuge in the Three Jewels for almost 30 years, the money-grabbing wife is very presumptuous and does not abide by the basic precepts and rites of Buddhism. This got me worried, with no tinge of happiness at all. I hope everybody understands this: the Bodhisattvas are wary of the seed of karma, while sentient beings fear the karmic fruits!

Today, let Master Dai Hu impart you the secret:

There is originally no sorrow in the affairs of this world
For inequality is the norm,
No greed can arise without attachment,
Why would there be sorrow.

All along, the friends in the Circus think that the audience loves to see stunts of a high difficulty level. That is because they are only watching passively. I am not. I am the friend who sincerely give you my true heart. Whilst you are performing your stunts of "high difficulty", I am the one who practices what I preach, endowing you with help and blessings.

www.masterdaihu.com/writing-to-my-friends-in-the-circus/