Hiding Amongst the Clouds A Proposal for Cloud-based Onion Routing - - PowerPoint PPT Presentation

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Hiding Amongst the Clouds A Proposal for Cloud-based Onion Routing - - PowerPoint PPT Presentation

Mar 02, 2023 22 likes •826 views

Hiding Amongst the Clouds A Proposal for Cloud-based Onion Routing Nicholas Jones Matvey Arye Jacopo Cesareo Michael J. Freedman Princeton University https://www.torproject.org/about/overview.html We and but... and C loud-based O nion

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Hiding Amongst the Clouds

A Proposal for Cloud-based Onion Routing Nicholas Jones Matvey Arye Jacopo Cesareo Michael J. Freedman Princeton University

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https://www.torproject.org/about/overview.html

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We

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and

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but...

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and

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C O R outing

loud-based nion

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Benefits, Risks, and Challenges

  • Potential benefits of cloud infrastructure
  • High performance
  • Adaptability to censorship
  • Economic challenges
  • New security problems
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Benefits of Cloud Infrastructure

Performance (latency, throughput) Censorship Resistance

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Performance

  • Individual nodes are higher bandwidth
  • Ability to add and remove nodes to meet demand

5:00 P .M.

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Performance

  • Individual nodes are higher bandwidth
  • Ability to add and remove nodes to meet demand

7:00 P .M.

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Performance

  • Individual nodes are higher bandwidth
  • Ability to add and remove nodes to meet demand

8:00 P .M.

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Performance

  • Individual nodes are higher bandwidth
  • Ability to add and remove nodes to meet demand

11:00 P .M.

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Performance

  • Individual nodes are higher bandwidth
  • Ability to add and remove nodes to meet demand

12:00 A.M.

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Performance

  • Individual nodes are higher bandwidth
  • Ability to add and remove nodes to meet demand

2:00 A.M.

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COR has higher throughput than Tor

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COR has higher throughput than Tor

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COR has higher throughput than Tor

US & International

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COR has higher throughput than Tor

US Only US & International

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COR has higher throughput than Tor

US Only US & International

7.6x speedup

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Multi-homed Datacenters are Harder to Monitor

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Multi-homed Datacenters are Harder to Monitor

Home

1-10 Mbps

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Multi-homed Datacenters are Harder to Monitor

Home

1-10 Mbps

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Multi-homed Datacenters are Harder to Monitor

Datacenter Home

1-10 Mbps

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Multi-homed Datacenters are Harder to Monitor

Datacenter Home

1-10 Mbps Sprint 10-100 Gbps

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Multi-homed Datacenters are Harder to Monitor

Datacenter Home

1-10 Mbps Sprint Level 3 10-100 Gbps

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Multi-homed Datacenters are Harder to Monitor

Datacenter Home

1-10 Mbps Sprint Level 3 AT&T 10-100 Gbps

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Multi-homed Datacenters are Harder to Monitor

Datacenter Home

1-10 Mbps Sprint Level 3 AT&T 10-100 Gbps

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Multi-homed Datacenters are Harder to Monitor

Datacenter Home

1-10 Mbps Sprint Level 3 AT&T 10-100 Gbps

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Multi-homed Datacenters are Harder to Monitor

Datacenter Home

1-10 Mbps Sprint Level 3 AT&T 10-100 Gbps

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Multi-homed Datacenters are Harder to Monitor

Datacenter Home

1-10 Mbps Sprint Level 3 AT&T 10-100 Gbps

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Multi-homed Datacenters are Harder to Monitor

Datacenter Home

1-10 Mbps Sprint Level 3 AT&T 10-100 Gbps

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Blocking Clouds Causes Collateral Damage

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Blocking Clouds Causes Collateral Damage

X

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Blocking Clouds Causes Collateral Damage

X X

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Blocking Clouds Causes Collateral Damage

X X X

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Blocking Clouds Causes Collateral Damage

X X X X

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Blocking Clouds Causes Collateral Damage

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Blocking Clouds Causes Collateral Damage

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Blocking Clouds Causes Collateral Damage

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Blocking Clouds Causes Collateral Damage

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Blocking Clouds Causes Collateral Damage

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Benefits of Clouds

  • Higher performance
  • Elasticity to scale to demand
  • Multi-homing and scale makes eavesdropping difficult
  • Elasticity forces censors to make hard choices:

collateral damage or unblocked access

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Economics

Cloud pricing is affordable for end users

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Cost of running COR in the cloud

  • Cloud providers charge for CPU and bandwidth
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Cost of running COR in the cloud

  • Cloud providers charge for CPU and bandwidth
  • CPU is cheap
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Cost of running COR in the cloud

  • Cloud providers charge for CPU and bandwidth
  • CPU is cheap
  • 100+ users on a 34¢/hr node
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Cost of running COR in the cloud

  • Cloud providers charge for CPU and bandwidth
  • CPU is cheap
  • 100+ users on a 34¢/hr node
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Cost of running COR in the cloud

  • Cloud providers charge for CPU and bandwidth
  • CPU is cheap
  • 100+ users on a 34¢/hr node
  • Bandwidth is dominant cost
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Cost of running COR in the cloud

  • Cloud providers charge for CPU and bandwidth

Amazon EC2 Pricing

  • CPU is cheap
  • 100+ users on a 34¢/hr node
  • Bandwidth is dominant cost
  • 100MB as low as 1¢
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Tor’s Total Bandwidth Cost in the Cloud

Approximately 900 MB/s 376 TB/month COR Cost: $61,200/month

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Security Challenges and Solutions

Involved Parties and Trust Model Building Tunnels Paying for Tunnels Learning About Relays

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Distributing Trust

  • Tor
  • Tunnels between volunteer relays
  • COR
  • Tunnels between clouds from different providers
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Is that sufficient?

  • Should users pay cloud providers directly?
  • Not anonymous: Credit cards and Paypal leak info
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Is that sufficient?

  • Should users pay cloud providers directly?
  • Not anonymous: Credit cards and Paypal leak info
  • Another layer of indirection: Anonymity Service Providers
  • Operate relays and pay cloud providers
  • Mask users’ identities
  • Accept anonymous payment for access
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System Roles

  • Cloud Hosting Providers (CHPs)
  • Provide infrastructure for COR relays
  • Anonymity Service Providers (ASPs)
  • Run relays and directory servers
  • Sell tokens
  • Redeemable for XX MB of connectivity
  • r XX amount of time
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System Architecture Example

CHP A CHP B ASP 1 USER DESTINATION SERVER

ENCRYPTED REQUEST TRAFFIC

ASP 2

Organizations used above are examples only

IP 1.1.1.1 IP 2.2.2.2

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System Architecture Example

CHP A CHP B ASP 1 USER DESTINATION SERVER

ENCRYPTED REQUEST TRAFFIC

ASP 2

Organizations used above are examples only

Cloud Hosting Providers

IP 1.1.1.1 IP 2.2.2.2

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System Architecture Example

CHP A CHP B ASP 1 USER DESTINATION SERVER

ENCRYPTED REQUEST TRAFFIC

ASP 2

Organizations used above are examples only

IP 1.1.1.1 IP 2.2.2.2

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System Architecture Example

CHP A CHP B ASP 1 USER DESTINATION SERVER

ENCRYPTED REQUEST TRAFFIC

ASP 2

Organizations used above are examples only

IP 1.1.1.1 IP 2.2.2.2

Anonymity Service Providers

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System Architecture Example

CHP A CHP B ASP 1 USER DESTINATION SERVER

ENCRYPTED REQUEST TRAFFIC

ASP 2

Organizations used above are examples only

IP 1.1.1.1 IP 2.2.2.2

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Circuit Construction Must be Policy Aware

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Circuit Construction Must be Policy Aware

  • Two relays within each datacenter
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Circuit Construction Must be Policy Aware

  • Two relays within each datacenter
  • Different entry and exit ASPs
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Circuit Construction Must be Policy Aware

  • Two relays within each datacenter
  • Different entry and exit ASPs
  • Different entry and exit CHPs
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Circuit Construction Must be Policy Aware

  • Two relays within each datacenter
  • Different entry and exit ASPs
  • Different entry and exit CHPs
  • ASP and CHP relays are contiguous within a circuit
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Paying for Access

  • Users purchase tokens
  • Redeem tokens for access (bandwidth or time)
  • Chaum’s e-cash:
  • Cryptographically untraceable
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How do users gain access?

  • Users need two things:
  • Tokens
  • COR Directory
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How do users gain access?

  • Users need two things:
  • Tokens
  • COR Directory
  • Solution: Bootstrapping Network
  • Low speed
  • High Latency
  • Free
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Adversaries enumerate and block ingress

  • Current technologies
  • Tor Bridges
  • Two separate problems:
  • COR Relays
  • High speed, low latency, not free
  • Bootstrapping
  • Low speed, high latency, free
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Summary Tor COR

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Summary Tor COR Secure

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Summary Tor COR Secure High Speed

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Summary Tor COR Secure High Speed Dynamic Scaling

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Summary Tor COR Secure High Speed Dynamic Scaling Adaptive to censorship

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Summary Tor COR Secure High Speed Dynamic Scaling Free Adaptive to censorship