A zero-approaching consumption on techs to know blockchain.

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Parallel universe from Northrop Grumman. It has nothing to do with this article. :)

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檢驗與設計人生方向的三個基本問題

筆者是圖靈證書圖靈鏈學院的執行長與共同創辦人,目前旅居美國柏克萊大學讀碩,靠運氣成為該校 2019 封面訪談人物,最快找到他的方式就是 Google 搜尋『 區塊鏈 天才 』,滿好笑誇張,他也很樂在其中。

目前 Jeff 僥倖佔據第一二五位。第四位是區塊鏈圈大前輩:小島

誒你的人生目標?

成為米其林三星主廚、Hollywood 電影製片、巡迴演唱會歌星、籃球明星、國際大企業老闆、美髮業第一把交椅,很多朋友常常會在飯局不亦樂乎的聊起人生目標,小時候的志向,但總是在長吁短嘆之中,過往熱情與期盼卻又煙消雲散,疲憊回到乏味工作與生活狀態,回到所謂現實。

這篇文希望用三個簡單問題,讓大家知道其實要實現一個夢想,或許不是那麼困難,或許有一線生機,或許有成為必然的機率。

問一:十年後的你此刻今天今時正在做什麼?

OMG 這個問題也太弱,不如關掉這篇文,繼續滑手機梗圖。

大家要注意,這個問題的關鍵在於『 回答的細節程度 』,你必須要非常鉅細靡遺的描繪出此刻(範例:我的十年後時間:33歲,2月4日下午3點整。)你正在做的事情以及你所處的狀態。

並且,試想最完美的想像,也就是你最期待的樣子,寫下來。

範例一:我正在陽台曬被子,天氣涼爽。31 歲。三重區的公寓 11 樓,兩房一廳。一隻狗,柯基,3歲半。與男友同居,暫時不計畫有小孩。工作為文案寫手,遠端工作,中型企業,月薪 5 萬 5,男友月薪 6 萬 2。有晚上 9:45沿著河岸慢跑習慣,會帶上柯基,牠跑比我快。


8個篇章,與一位23歲學生創業家的自白

我是 Jeff 胡耀傑,這個月即將邁入 23 歲,生於臺灣,學於香港,深造於瑞士與美國。雖在柏克萊、內華達、清大、政大與其他學校的 17 次演講中,講述了自己的故事,卻值此方能提筆留篇,徒望能為臺灣甚至華語區的學生,發現一個思想革新的平行宇宙。

你,或是我們,都值得輕鬆成功


重演2014年的 Partial Payment 漏洞利用,罪咎誰當?

背景

台灣加密貨幣交易所 BitoPro 於台灣時間2019年4月28日上架 Ripple 瑞波幣(XRP)開放交易,並於台灣時間2019年5月1日遭到駭客利用 Partial Payment 特徵進行漏洞攻擊,可能損失約200萬台幣 (根據 BlockTempo官方說明)

漏洞在哪?

漏洞來自於 Ripple 支付的特別功能

Ripple 早期推出多種有別於傳統支付 (Payment) 的交易格式,包含非默認路徑支付 (NoDirectRipple)、部分支付 (PartialPayment)、限定匯率支付 (LimitQuality),並採用特定的支付標籤 (Transaction Flag) 作為標記:


Part 1 (#25–#13)

Revealing techniques of 25 successful attacks on blockchain: from 2010 to 2018, $1.8+ billion USD.

Blackhat from Wallpaper Cave

Overview

Hacks on blockchain have always been controversial topics throughout history. Countless exchanges and platforms have been exploited by talented attackers who made away millions of dollars without leaving a trace.

Numerous great articles have been focusing on the discussion of the procedure and impact of an attack, but this article steps aside to emphasize the technical approach of the attack. No worries. Rather than going through sophiticated techie murmurs, this post translates the attack method into a format that is more friendly for children and grandparents.

Various hacks have different levels of details opened to the public. Some hacks disclosed…


The private key was compromised; any ether drained right away. Yet five kitties left helpless.

This afternoon, my professor messaged me saying that his unattended Github repo accidentally revealed the private key to the public. A malicious scanner captured the key, and now draining all the funds.

It happened

Any ether goes in the wallet is drained right at the moment…

Figure 1: Ethers are being drained…

Money is no issue, but the kitties matter

Though there are no more ethers in the wallet that we can save, five crypto kitties are stuck. Without any available gas, it seemed impossible that we can rescue the kitties from the tragedy.

Two Alternatives

We soon came up with two alternatives:


當你只剩兩週的時間,與一個GRE 330的目標

BlockCity’18 Speakership — Jeff Hu

筆者Jeff Hu,2018/12/14透過兩週未滿的準備時間,在許多前輩同輩的鼓勵加持下,勉強幸運的在台南考場取得329的分數(Q: 170, V: 159)。如果你正在讀這篇文,相信你的時間和兩週前的我同樣緊迫,我們將直接講述接下來時間可以如何最大化你的成績 :)

感謝詞

儘管在學測的僥倖之後,我仍以為英文考試是不需要補習班的,直到我遭遇首刷 GRE 的慘敗。這篇文要獻給 Mason GRE ,一個完美證實補習班對 GRE 考試有直接助益的學習歷程。透過 Mason 與諸位老師四週的開導與犀利的試題分析,才能在今日此刻昂首闊步走進 UC Berkeley 斑駁的銅綠色大門。

要點整理

GRE是個巨大題庫,所有你練過的題目都有可能出現在你的考試裡

我考前練的單字題數僅僅500題(機經前兩百 + MasonGRE六題本)。考試抽中QV-QVQ,在僅有的40題Verbal考題中,我發現其中有五題好像…恩xd

Know what’s coming.

GRE考試共七個試題模塊,上半場包含四個,下半場三個。上半場會先完成作文的Issue與Argument兩塊,接著看運氣可能是VQ (字彙/數學)或是QV,兩塊。下半場依序就會是VQV (字彙/數學/字彙)或是QVQ,三塊。

去報補習,或是去報MasonGRE

事實上,我去年曾經天真的抱著紅寶書,背了亂七八糟的單字然後考了319…。考試的路,你可以自己跑,但是不要拒絕補習班給你的腳踏車。

找一起考試的伴侶

一個人準備是很孤單的。這裡也要感謝我的考伴Lee Ting Ting,兩個人一起待在咖啡廳有個即時的討論對象,會是非常高效率的準備方式。也許我很邊緣,所以不建議人數太多的討論會容易分心。當然你不邊緣你可以去…

補習不代表你一定要坐在教室聽三小時

一場MasonGRE的講課佔三小時,雖然老師都非常的強和風趣,補充許多課外知識,不過我實際只參加了兩堂半的課。其餘聽錄播(也就是補課錄影帶)!用1.5倍放,還可以跳過非精彩片段:整場180分鐘減中場10分鐘除以1.5倍是113分鐘,也就是說別人聽兩堂課的時間,你可以聽三堂課,多麼享受。

效率至上

把準備過程的項目分成:累,一般,輕鬆,三種類型。隨時交替,每當做完一項累慘的項目,不應該休息狂打積分,而是切換成輕鬆的項目持續進行。找個固定抒壓的方式也是很重要,比方說居酒屋或是電影院。

Only acquire what’s required

只學你需要的。別人會說哇GRE就是磨練你廣泛的英語能力,那你叫他也去考。之前無意看到語言大師秋山燿平的影片,這次我用2倍速看lol,裡面兩句話最吸引我:

推薦準備資料

自己生成的準備資料

關於前面的單字卡我自己生成了2000單精粹,機經單,與數學單三個表單。還好玩的寫了個爬蟲把機經考過的單字全部爬下來,並依照出現頻率排放。

考試解題順序

放輕鬆,然後想著在場的大家都比你弱,就沒問題了。 — Jeff Hu, 2018

作者介紹

筆者Jeff Hu靠持續的運氣拿著75級分與全額獎學金在香港科技大學讀CS,曾在矽谷實習三個月與瑞士洛桑聯邦理工交換半年。現在一邊在慕尼黑與上海發表論文,一邊在台灣營運自己在香港的新創Turing Chain,玩轉區塊鏈。主要興趣是旅遊,寫詩,與魔術接案表演。

聯絡或追蹤作者


ASTRAEA: A Decentralized Blockchain Oracle — John Adler, Ryan Berryhill, Andreas Veneris, Zissis Poulos, Neil Veira, and Anastasia Kastania. (2018)

The original paper can be found here.

I especially have the predilection for the following quote from a great Medium post, The State of Decentralized Oracles, by John Adler.

Scaling makes blockchains usable while oracles make blockchains useful.

What is an Oracle?

Oracle is a crucial smart contract that is specially designed to be the I/O for a blockchain. It absorbs external data from the outside world, which is used to be unachievable since that a blockchain is usually confined to computations of on-chain data.

Oracle image from Sci-fi and Fantasy Network

Problem of Oracle

Relying heavily on an individual Oracle contract can lead to another problem: single-point of failure. When the Oracle smart…


Technical walkthrough on how to reveal states in contract private variables

Spammy Fun Image from Blog 4Linux

Foreword

This is a technical tutorial that takes you through the exact steps of retrieving states from the private variables of an Ethereum smart contract. All the techniques here can be applied to real life.

This tutorial is encouraged by Ethernaut Lvl8 challenge.

What you might need

truffle / ganache-cli / Node.js / curl

Contract code

Here is a very simple contract with four private variables with four different types: uint256, boolean, uint16, and mapping. The values are initialized when the contract is deployed to the network. Let’s assume the contract has been deployed to “0xb3b4546a6d8c8cd1081ac94a7e06a24b207c863d”.

contract PrivateStorage {
// Private Variables…


Bitcoin: A Peer-to-Peer Electronic Cash System — Satoshi Nakamoto (2008)

The original paper can be found here.

Preface

This is a technical summary of the well-known Bitcoin paper that takes you a step forward to grasp Bitcoin’s underlying techs in layman terms. Feel free to check out the original paper to get more details.

Bitcoin image from Bitcoinist.com

One sentence break-down

Bitcoin

A digital currency in a peer-to-peer network without third-party control.

Bitcoin blockchain

Ongoing chain of hash-based PoW on timestamped transactions.

Major problem

Double spending.

Transaction

Transfer a coin

A Sender signs the following message to approve a transfer:

Message = (HASH of previous transaction + PUBLIC KEY of the Receiver)

Jeff Hu

Co-founder & CEO @ TuringChain.tech / Scholar @ UC Berkeley Blockchain Lab / Entrepreneur, blockchain researcher, magician, and poet

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