TOR, OTR & BITCOIN. , .

browsing Tor

Onion routing

chat OTR

Forward secrecy

Deniability

bitcoin

...

OTR :

Linux Windows, Pidgin & OTR:

https://www.pidgin.im/

https://otr.cypherpunks.ca

Mac, Adium:

https://adium.im/

Tor

https://www.torproject.org/

IP ...

Internet

( )

IP

...

Demo IP

http://wtfismyip.com/

Tor

IP

Tor Browser Bundle

Tor browser

https://panopticlick.eff.org/

features

Javascript, Flash, Java, Silverlight

browser

Tor Browser Bundle

browser

HTTPS everywhere

Javascript!

Onion routing

server 3tor nodes

node

, 3 tor

Tor nodes

node public key

encrypt public key 3 nodes

Exit & Relay nodes

nodes

/ HTTPS

node exit node

by default

traffic

node relay node

Relay node

Exit node

Demo

http://wtfismyip.com Tor

Tor: browsing

Tor

SOCKS proxy

Application (Firefox)

Onion routing (Tor)

Internet (IP)

Transport (TCP)

!

Tor

.. Torrents

IP

DNS leaks: resolve IP DNS Tor

Tails: Linux Tor

Hidden services

client, server

Internet

Clearnet: browser

Darknet Deep web: Tor

6 Tor relay hops

Tor

, exit node

OTR: Off-the-record

chat

chat

Facebook

Skype

Google Talk

MSN

chat

Alice Facebook

Facebook

Facebook Bob

Bob

AliceBOB

HTTPS HTTPS

chat

To Facebook chat !

man-in-the-middle

,

AliceBOB

HTTPS HTTPS

end-to-end

Alice Bob

Facebook

AliceBOB

OTR client

DSA

client

...

Perfect Forward Secrecy

Diffie-Hellman

.. 2

2 DSA , !

Deniability

O Bob Alice

Bob Alice

OTR

GPG

OTR GPG

http://petrosagg.com/otr.txt

https://dionyziz.com/otr

OTR

OTR chat GPG OTR

GPG

GPG

OTR demo

Ima

ge

ca

rbo

nis

m

...

& multibit

https://multibit.org/

bitcoin?

Online

(?) $

Wei Dai, 1998: Bmoney (cypherpunks)

Nick Szabo, 2005: Bit gold

Satoshi Nakamoto, 2008: Bitcoin: A Peer-to-Peer Electronic Cash System"

2009: bitcoind open source C++

Casper Paramount

Satoshi Nakamoto?

bitcoin

;

bitcoin paper

bitcoin

IRC bitcoin

bitcointalk forum

bitcoin

...

...

Satoshi ?

bitcoin

;

bitcoin paper

bitcoin

IRC bitcoin

bitcointalk forum

bitcoin

...

...

Satoshi ?

...

;

Nick Szabo?

Wei Dai?

Dr Vili Lehdonvirta & Michael Clear?

Neal King, Vladimir Oksman & Charles Bry?

Shinichi Mochizuki?

Jed McCaleb?

Dread Pirate Roberts?

, , .

: Online

.. Visa, MasterCard

.. PayPal ...

:

...

$

Federal Reserve Bank ( )

:

100

1

100

1

;

bitcoin

Peer-to-peer

1 second

10

!

$

-

:

;

... ;

Ima

ge

F

L1

P5

1D

3

Peer-to-peer bitcoin

/

broadcast

Hash functions

One-way

H( x ) = y

y x

x y

x y

y x?

Collision resistance

y, x :

H(x) = y

, :

H() = H()

d c, n :

H(c || n) < d

d

hash

Bob Alice

12mBTC

m 12mBTC Aliceh H ( m )s signBs( h )

s

0BTCverifyBp( m, s )

12mBTC

0BTC

Bo

b

Nic

ke

lod

eo

n; A

lice

D

isn

ey

;

Bob

Alice

Bob

Broadcasting

,

#137 #152 #312

5BTC 5BTC

#111 #222 #555

2BTC 2BTC

;

Bp, Bs

Ap, As

verBp( m1, s1 )

m2 12mBTC PCh2 H( m2 )

Cp, Cs

verAp( m2, s2 )m1 12mBTC Aph1 H( m1 )

s1 signBs( h1 ) s2 signAs( h2 )

Bo

b

Nic

ke

lod

eo

n; A

lice

D

isn

ey

(.) .

(.) .

=

coin1 signS0( H( coin0 || P1 ) )

coin2 signS1( H( coin1 || P2 ) )

coin3 signS2( H( coin2 || P3 ) )

Ima

ge

1

Dysle

xia

1

Ima

ge

S

ato

sh

i N

aka

mo

to

{"hash":"96f5e5394726ca5","ver":1,"in":[{

"prev_out":{"hash":"87750ccbebf71042d","n":0

},"scriptSig":"30440397d0c2 49d0c04a7e52"

}],"out":[{

"value":"0.71430000","scriptPubKey":"OP_DUP OP_HASH160

99fa78c49d99f58c8dd OP_EQUALVERIFY OP_CHECKSIG"

}]}

;

=

>= ;

!

;

Blocks

block

hash block

block hash

block

block

hash

Ima

ge

S

ato

sh

i N

aka

mo

to

blocks?

...

blocks

Proof-of-work

blocks nodes broadcast

block

block

Ima

ge

S

ato

sh

i N

aka

mo

to

nonce 000000

while H( block || nonce ) < 100000:

nonce nonce + 1

broadcast( block )

Difficulty

block

blocks

blocks genesis

genesis

(2009)

Ima

ge

th

eym

os

block

block

block

blocks

block

blocks

CPU

bitcoin

block = bitcoin

: 25BTC / block

Difficulty

CPU

block 10

: 3,129,573,175

Ima

ge

th

eym

os

Elgamal (DSA)

Hash function

SHA256( SHA256( _ ) )

SHA256( _ )

bitcoin 17 2012: 167,000 blocks

1BTC = 3.27 8.3 BTC 27,000,000 hashing = 9THz

9 2013: 1BTC = 73

19 2014: 286,000 blocks

1BTC = 450 12.4 BTC 5,600,000,000 hashing = 30,000Thz

Litecoin

Scrypt SHA

Dogecoin

Namecoin

Decentralized DNS

Twister

Decentralized Twitter

Bitmessage

Decentralized SMS

Zerocoin

browsing Tor

Onion routing

chat OTR

Forward secrecy

Deniability

bitcoin

!

Internet

chat

bitcoin

! ;

bitcoin.org

Twitter: @dionyziz, @petrosagg

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