[tor-bugs] #261 [Core Tor/Tor]: getinfo orconn-status sometimes crashes

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#261: getinfo orconn-status sometimes crashes
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 Reporter:  goodell       |          Owner:  (none)
     Type:  defect        |         Status:  closed
 Priority:  Low           |      Milestone:
Component:  Core Tor/Tor  |        Version:
 Severity:  Blocker       |     Resolution:  Fixed
 Keywords:                |  Actual Points:
Parent ID:                |         Points:
 Reviewer:                |        Sponsor:
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Changes (by nickl):

 * severity:   => Blocker


Comment:

 Found this whitepaper: https://eprint.iacr.org/2018/162.pdf

 Not sure if it is still any use.

 Untagging Tor: A Formal Treatment of Onion Encryption


 Abstract. Tor is a primary tool for maintaining anonymity online. It
 provides a low-latency, circuit-based, bidirectional secure channel be-
 tween two parties through a network of onion routers, with the aim of
 obscuring exactly who is talking to whom, even to adversaries control-
 ling part of the network. Tor relies heavily on cryptographic techniques,
 yet its onion encryption scheme is susceptible to tagging attacks (Fu and
 Ling, 2009), which allow an active adversary controlling the first and
 last node of a circuit to deanonymize with near-certainty. This contrasts
 with less active traffic correlation attacks, where the same adversary can
 at best deanonymize with high probability. The Tor project has been ac-
 tively looking to defend against tagging attacks and its most concrete al-
 ternative is proposal 261, which specifies a new onion encryption scheme
 based on a variable-input-length tweakable cipher.
 We provide a formal treatment of low-latency, circuit-based onion en-
 cryption, relaxed to the unidirectional setting, by expanding existing
 secure channel notions to the new setting and introducing circuit hiding
 to capture the anonymity aspect of Tor. We demonstrate that circuit hiding
 prevents tagging attacks and show proposal 261’s relay protocol is circuit
 hiding and thus resistant against tagging attacks.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/261#comment:5>
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