IntroductiontoCryptographicCurrencies详解.docxVIP

Introduction to Cryptographic Currencies Claudio Orlandics.au.dk/~orlandi Thanks to: Jon K. Sørensen and Peter S. Nordholt Leave while you can! I will NOT talk about: Politics Economics … Coming up next: Algorithms Cryptography … Outline Part 0: a little history Part 1: TheoryCoin How to create coins How to transfer coins How to store coins Part 2: diff( , ) Part 3: Problems and issues crypto currency The 1990sDavid Chaum and anonymous ecash “The difference between a bad electronic cash system and well-developed digital cash will determine whether we will have a dictatorship or a real democracy” (attributed to Chaum) Anonymous payments ”withdraw” ”withdraw” M or L? Chaum’s anonymous e-cash anonymous secure (no double-spending) only transfer (no creation/storage) …and bankrupted in 1999 The advent of Bitcoin 2009: Bitcoin announced by Satoshi Nakamoto Pseudonym for person or group of person 2009-2011: slow start… 2011-2013: Silk Road and Dread Pirate Roberts End 2013: Bitcoin price skyrockets and the world notices! Outline Part 0: a little history Part 1: TheoryCoin How to create coins How to transfer coins How to store coins Part 2: diff( , ) Part 3: Problems and issues TheoryCoin: How to create money Everyone tries to solve a puzzle The first one to solve the puzzle gets 1 TC The solution of puzzle i defines puzzle i+1 TheoryCoin: How to create money H L ∈ {0,1}* R ∈ {0,1}* T ∈ {0,1}d SolvePuzzle(L){ repeat{ R = my_name || i++ T = H(L,R) }while(T ≠ 0d) return R } The puzzle: given L, find R such that T=0d (a random function) * aka Proof-of-Work TheoryCoin: (coins to ppl)How to create money H x0 = Start! x1 =(P1, i1) 000…000 x2=(P2, i1) H 000…000 x3=(P3, i3) H 000…000 P3 P1 P2 x1 x1 x2 x2 x3 x3 * aka the blockchain x7=(P3, i7) x6=(P3, i6) x5=(P5, i5) x0=Start! x1=(P1, i1) x2=(P2, i2) x3=(P3, i3) x4=(P4, i4) TheoryCoin: How to create money * aka the 51% attack TheoryCoin: How to create money Recap: