The Silk Road: - PowerPoint Presentation

Slide1

The Silk Road: An Online Marketplace

By Adam CroninSlide2

Project Overview

Main goal: Research The Silk Road and how it provides anonymity

Mechanisms for providing anonymity

Failures in anonymity Slide3

What is The Silk Road?

An anonymous online marketplace created to facilitate the online sales of both legal and illegal items

People around the world can trade with each other without divulging their identity

A means of circumventing buying and selling restrictions that may be in effect due to geographic locationSlide4

Anonymity in a Marketplace

Requirements for an anonymous online marketplace

Accessing the site

Ability to post/advertise items for sale

Ability to browse available items

Transactions

Sending item from seller to buyerSlide5

The Silk Road’s Solution

Requirements for an anonymous online marketplace

Accessing the site

 Tor

Ability to post/advertise items for sale

 Register Account

Ability to browse available items

 Register Account

Transactions

 Bitcoin

Sending item from seller to buyer

 Still have to give an address…Slide6

Tor

The Tor browser is essentially a means of anonymously sending network data

Data is sent through a series of nodes

Each node is a volunteer

Each node only knows the previous node and the next node so single compromised node isn’t a huge issueSlide7

How Tor Works

Tor installs an Onion Proxy onto the user’s computer

The OP creates a virtual circuit that defines the path through the Tor nodes that leads to the user’s end destination

Tor downloads list of all potential Tor nodes in the network

Uses the list to choose an Entry node, an Intermediate node, and an Exit nodeSlide8

How Tor Works (Cont’d)

Creates a Transport Layer Security (TLS) connection between itself and the Entry Node

Uses encryption to prevent eavesdropping, tampering, or message forgery

Then starts the process of creating the virtual circuit

To create a VC, can send three commands: create, extend, and deleteSlide9

Tor

Onion Proxy

Destination ServerSlide10

Create TLS Connection

Onion Proxy

TLS, K1

(Transport Layer Security)

Destination ServerSlide11

Create Command on Entry Node

Onion Proxy

Destination Server

CreateSlide12

Create Command on Intermediate Node

Onion Proxy

Destination Server

Extend

CreateSlide13

Create Command on Exit Node

Onion Proxy

Destination Server

Extend

CreateSlide14

Send Message

Onion Proxy

Destination Server

Extend

CreateSlide15

Traditional Online Transactions

Traditional online transaction requires a middle man

Buyer

 Bank  Seller

Disadvantages of trusted third-party

A

ccess to user’s money

Knowledge of all transactions and who with

Transactions can be disputed and reversedSlide16

Bitcoin

A peer-to-peer electronic cash system

Goal: move away from the traditional form of cash exchange

Remove trusted third-party (ex: banks)

Instead of third-party, broadcast every transaction to all nodes on the Bitcoin network

Transactions can’t be reversed or disputedSlide17

Bitcoin

Each user holds their Bitcoins in a wallet which is referenced during transactions

Bitcoin characterized as a “chain of digital signatures”

Each user has a public and private key so that only the owner of a wallet can transfer Bitcoins

During a transaction, a signature is created and added to the coin

Private key used to generate signature

Public key used to verify the signatureSlide18

Failures in Anonymity

Tor by itself doesn’t encrypt data leaving the exit node or returning to the exit node

A passive attacker who watches both the sender and the receiver could link the two with high probability

Compromised TLS key for Onion Proxy could lead to impersonation

Receiver of package must still give an addressSlide19

Failures in Anonymity

The Silk Road has been shut down twice and the people running the site were arrested

A new clone is started up every time The Silk Road gets shut downSlide20

References

[1] Christin, Nicolas. "Traveling the Silk Road: A Measurement Analysis of a Large Anonymous Online Marketplace." (2012): n.

pag

. Carnegie Mellon, 30 July 2012. Web. 12 Oct. 2015. <https://www.cylab.cmu.edu/files/pdfs/tech_reports/CMUCyLab12018.pdf>.

[2]

Dingledine

, Roger, Nick Mathewson, and Paul

Syverson

. "Tor: The Second-Generation Onion Router." (

n.d.

): n.

pag

. Web. 5 Oct. 2015. <

https://svn.torproject.org/svn/projects/design-paper/tor-design.pdf

>.

[3]

Dierks

, T. & C. Allen. “The TLS Protocol Version 1.0.” January 1999. (6 November 2015

)

[4]

Nakamoto

, Satoshi. "Bitcoin: A Peer-to-Peer Electronic Cash System." (n.d.): n. pag. Web. 5 Oct. 2015. <https://bitcoin.org/bitcoin.pdf>.

[5] Biryukov, Alex, and Ivan Pustogarov. "Bitcoin over Tor Isn't a Good Idea." 2015 IEEE Symposium on Security and Privacy

 (2015): n. pag. 8 Jan. 2015. Web.