Timestamp /16 at LBL, sampled 1-in-1K 2nd /16, sampled 1-in-1K - - PowerPoint PPT Presentation

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Timestamp /16 at LBL, sampled 1-in-1K 2nd /16, sampled 1-in-1K - - PowerPoint PPT Presentation

Mar 06, 2024 124 likes •373 views

Timestamp /16 at LBL, sampled 1-in-1K 2nd /16, sampled 1-in-1K Number of relays 8000 6000 Relays 4000 Bridges 2000 0 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 The Tor Project https://metrics.torproject.org/ Directly

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Timestamp

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/16 at LBL, sampled 1-in-1K 2nd /16, sampled 1-in-1K

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2000 4000 6000 8000 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

The Tor Project − https://metrics.torproject.org/

Relays Bridges

Number of relays

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2 000 000 4 000 000 6 000 000 2012 2013 2014 2015 2016 2017

The Tor Project − https://metrics.torproject.org/

Directly connecting users

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50 100 150 200 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

The Tor Project − https://metrics.torproject.org/ Bandwidth (Gbit/s)

Advertised bandwidth Bandwidth history

Total relay bandwidth

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10 20 30 2010 2011 2012 2013 2014 2015 2016 2017

The Tor Project − https://metrics.torproject.org/

Measured times on all sources per day Median 1st to 3rd quartile

Time in seconds to complete 50 KiB request

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(from 2008)

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2000 4000 6000 8000 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

The Tor Project − https://metrics.torproject.org/

Relay flags Running Exit

Number of relays with relay flags assigned

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Well-known: g, p Secret: x, y A⟶E⟶B: gx mod p B⟶E⟶A: gy mod p Derived key: gxy

Diffie-Hellman Exchange

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Well-known: g, p Secret: x, y A⟶M⟶B: EB(gx mod p) B⟶M⟶A: gy mod p, Hash(K=gxy) Derived key: gxy

Tor DHE

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Well-known: g, p Secret: x, y A⟶M: EB(gx mod p) M⟶B: EB(gx' mod p) B⟶M: gy mod p, Hash(K=gx'y) M⟶A: gy' mod p, Hash(K=g?) Derived key: gxy ? gx'y ? gxy' ? gx'y' ?

Tor DHE: Mallory Attacks?

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Well-known: g, p Secret: x, y; x' = y' = 0 A⟶M: EB(gx mod p) M⟶B: EB(gx' mod p) = EB(g0 mod p) = EB(1 mod p) B⟶M: gy mod p, Hash(K=gx'y) = Hash(g0) = Hash(1) M⟶A: gy' mod p = 1 mod p, Hash(K=1) Derived key: gxy ? gx'y = gxy’ = gx'y’ = 1

Tor DHE: Mallory Attacks!

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Well-known: g, p Secret: x, y A⟶M⟶B: EB(gx mod p) B⟶M⟶A: gy mod p, Hash(gx || gy || K=gxy) Derived key: gxy

Tor DHE Fixed

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