加密貨幣與區(qū)塊鏈

CryptoCurrency&

BlockChain加密貨幣與區(qū)塊鏈Agenda?SHAFamily?PoS:

Proof

of

Stake?Mining

Industry?

Wallets?Quantum

ComputerSHAFamily3Merkle-Damg?rdConstruction

forSHA-1/

SHA-2ImageCourtesyhttp://joncave.co.uk/2012/08/i-captured-the-flag4lOneiterationina

SHA-2familycompressionfunctionl

The

bluecomponentsperformthefollowingoperationsMa(A,B,

C)=(AΛB)B(AΛC)B(BΛC)ch(E,F,

G)=(EΛF)B(-E入G)l

The

bitwiserotationusesdifferentconstantsforSHA-512l

ThegivennumbersareforSHA-256l

田isadditionmodulo232SHA-256http://en.wikipe/wiki/SHA-25Hash

Function

Usages?

DoubleSHA256,i.e.,SHA256(SHA256())?

MerkleTree?

Block

Hash?Transaction

ID?

RIPEMD160(SHA256())?Bitcoin

Address6?“FindingCollisions

inthe

Full

SHA-1”,CRYPTO2005,

LectureNotes

inComputer

Sciencevol.3621,

pp.

17-36?

王小云

?山東大學數(shù)學系?

RumpsessionofCRYPTO2004?Security:280

→263

computationsCollisionsonSHA-17SHA-3CompetitionWinner:Keccak?

Designers:?

GuidoBertoni(Italy)

ofSTMicroelectronics?

JoanDaemen(Belgium)ofSTMicroelectronics?

GillesVan

Assche(Belgium)ofSTMicroelectronics?

Micha?l

Peeters(Belgium)ofNXPSemiconductors?

Notveryfastinsoftwareimplementation,

but

in

hardwareimplementationsitisnotablyfasterthanallotherfinalists?

In

its

largest

instance,thestateconsistsofa5×

5

array

of

64-bitwords,

1600bitstotal?

Reducedversionsaredefinedforsmallerpower-of-2wordsizes

wdown

to

1

bit(25

bitstotal

state)?

Smallerstatesizescanbeusedtotestcryptanalyticattacks?

Intermediatestatesizes(e.g.,from

w

=

4,

100bits,to

w

=32,800bits)alsoprovidepractical,lightweight,

alternatives8SHA-3

/

Keccak:SpongeConstruction9EthashforEthereum/en/what-is-the-algorithm-of-ethash-mining/Keccak25610ApplicationsofHash

Functions?Verifyingthe

IntegrityofFilesor

Messages?

PasswordVerification?

Fileor

Data

Identifier?

PseudorandomGeneration&

Key

Derivation?

Proof-of-Work(POW)/wiki/Cryptographic_hash_function11ProofofStake12ProofofWork(PoW)lA

Proof-of-Work

(PoW)system(orprotocol)is

aconsensusmechanism,whichdetersdenialofserviceattacksandotherserviceabusessuchas

spamon

anetwork

byrequiringsomeworkfromtheservicerequester,usually

meaningprocessingtimeby

a

computerlAkeyfeatureoftheseschemesistheirasymmetry:the

work

mustbemoderatelyhard

(yet

feasible)on

therequestersidebuteasytocheckfortheservice

providerlTheconceptwas

inventedbyCynthia

Dworkand

MoniNaoraspresentedina

1993

journal

article,

andthe

term"ProofofWork"orPoWwasfirstcoinedandformalizedina

1999paperbyMarkus

Jakobsson

andAri

Juels13/wiki/Proof_of_workProofofStake(PoS)l

The

proof

of

stake

model

requires

a

user

to

lock

hisEthers

(for

the

case

of

Ethereum)

into

smartcontracts

inorderto

beeligibleforvalidating

blocksl

Theequivalency

ofhavinga

large

hashrate

in

PoW

isstaking

more

money

inthecase

of

PoSl

A

personwithahigher

hashrate

had

more

probabilityof

validating

a

block

in

PoW

,similarly,a

person

whostaked

more

hasthesame

powers

here/pos-will-bring-more-security-to-ethereum-than-pow-vitalik-buterin/14ProofofStake(PoS)l

For

a

hacker

to

add

blocks

in

the

blockchain,

hewould

havetostake

a

lotof

moneyl

Even

after

the

adding

of

blocks,there

would

be

atimeforachallengertocheck

and

seewhether

there

isasignofsuspiciousactivity

orwrong

validationsonthe

blockchain

inwhichcase

hewouldchallenge

thevalidation

andthe

hackerwould

loseallofhisstaked

money/pos-will-bring-more-security-to-ethereum-than-pow-vitalik-buterin/15Mining

Industry16https://blockcast.it/2017/10/04/blockcast-interview-first-mining-machine-in-taiwan/17/cryptocurrency-miners-rent-boeing-747s-2017-718.tw/News/ViewCateNews.aspx?newsid=164785&cateid=kjmd19.tw/News/ViewCateNews.aspx?newsid=164785&cateid=kjmd20https://unwire.pro/2018/05/14/nvidia-reports-first-quarter-crypto-sales/news21/money/story/5612/317819322Wallets23PaperWallets24PaperWallets25HotvsColdWalletl

HotWalletlAhotwallet

referstoa

Bitcoinwalletthatis

online

and

connectedinsomewaytothe

InternetlIt

isatermthat

refersto

bitcoinsthat

are

not

being

keptin

cold

storagel

ColdStoragelColdstorageinthecontext

of

Bitcoin

refersto

storingBitcoinsofflineandspendingwithouttheprivate

keyscontrollingthemeverbeing

onlinelThisresiststheftby

hackersandmalware,

and

is

oftenanecessarysecurity

precautionespeciallydealingwith

largeamountsofBitcoinhttps://en.bitcoin.it/wiki/Hot_wallet

https://en.bitcoin.it/wiki/Cold_storage26.tw/article/50035/hitcon-cmt-2018-blockchainhttps://www.i.tw/news/1248611

42328/

安瀚科技29QuantumComputer30名詞解釋?

Quantum

Computing

量子計算–利用量子力學特性進行計算?

Quantum

Cryptanalysis

量子破密–

以量子計算破解加密系統(tǒng)?

Shor’s

algorithm

→

公鑰加密系統(tǒng)?

Grover’s

algorithm

→

對稱加密系統(tǒng)?Post-Quantum

Cryptography

后量子加密–(PQC)可抵抗量子計算機攻擊之公鑰加密31量子破密的里程碑?1994

:

Peter

Shor

(AT&T’s

Bell

Labs發(fā))現(xiàn)重要算法“Shor’s

Algorithm”

，若實現(xiàn)于成熟的大規(guī)模(large

scale,2000+qubits)量子計算機，可破解當今幾乎所有公鑰加密系統(tǒng)?

2001

:首次執(zhí)行Shor’s

Algorithm,

IBM的

7-qubit量子計算機可分解

15=3

×

532IBM’s

50-qubitquantum

computerNovember

2017Intel’s

49-qubit

chip“Tangle-Lake”January

2018近年量子計算機發(fā)展加速Google’s

72-qubitchip“Bristlecone”March

201833現(xiàn)今最大商用量子計算機IBM’s

53-qubit

Quantum

Computer

October

201934未來量子計算機發(fā)展預測?

When

will

a(large-scale)

quantumcomputer

be

built?–

“There

is

a

1

in7

chance

that

somefundamental

public-keycryptowillbe

broken

by

quantum

by2026,anda

1

in2