Opened 4 years ago

Last modified 7 weeks ago

#17591 assigned enhancement

Use channel padding to obscure circuit setup

Reported by: mikeperry Owned by:
Priority: Medium Milestone: Tor: unspecified
Component: Core Tor/Tor Version:
Severity: Normal Keywords: mike-can, term-project-ideas, padding, intersection-attack
Cc: asn, yawning, special, dgoulet, teor, mikeperry Actual Points:
Parent ID: Points: 6
Reviewer: Sponsor:


We could use the code from #16861 to pad more often during circuit setup to defend against circuit fingerprinting by someone who is watching the guard node. This would be somewhat complicated, as it would need special timers that could be called more often than once per second (or could chain off eachother), but it could be done.

On the client side, it could be done from any of the onionskin or circuit launching calls. On the relay side, we probably would need some logic around padding more often so long as we're still getting RELAY_EARLY cells, or similar.

It's also debatable in general as to if circuit fingerprinting is still successful if you're just watching the guard. If it's not, this may not be worth doing (since it won't protect anyone from a malicious or compromised guard).

Child Tickets

Change History (14)

comment:1 Changed 4 years ago by mikeperry

Cc: asn yawning special dgoulet added

comment:2 Changed 4 years ago by teor

Cc: teor added

comment:3 Changed 4 years ago by nickm

Milestone: Tor: 0.2.9.x-final

comment:4 Changed 4 years ago by nickm

Keywords: 6s194 added

comment:5 Changed 4 years ago by nickm

Keywords: term-project-ideas added; 6s194 removed

These tickets were tagged "6s194" as ideas for possible term projects for students in MIT subject 6.S194 spring 2016. I'm retagging with term-project-ideas, so that the students can use the 6s194 tag for tickets they're actually working on.

comment:6 Changed 3 years ago by nickm

Points: large

comment:7 Changed 3 years ago by isabela

Points: large6

comment:8 Changed 3 years ago by mikeperry

Milestone: Tor: 0.2.9.x-finalTor: 0.2.???

Moving this out post 029. I think that we might want to do this using circuit-level padding anyway.

comment:9 Changed 3 years ago by teor

Milestone: Tor: 0.2.???Tor: 0.3.???

Milestone renamed

comment:10 Changed 3 years ago by nickm

Keywords: tor-03-unspecified-201612 added
Milestone: Tor: 0.3.???Tor: unspecified

Finally admitting that 0.3.??? was a euphemism for Tor: unspecified all along.

comment:11 Changed 2 years ago by nickm

Keywords: tor-03-unspecified-201612 removed

Remove an old triaging keyword.

comment:12 Changed 2 years ago by nickm

Keywords: padding intersection-attack added

comment:13 Changed 2 months ago by gaba

Cc: mikeperry added
Owner: mikeperry deleted
Status: newassigned

comment:14 Changed 7 weeks ago by cypherpunks

it is important to pad the RELAY_EARLY cells count. because using vanguards would make you stand out else!

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