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Hidden service performance
by David Goulet 19 Dec '14

19 Dec '14

Hello tor-dev, This email is to detail the work being done on a framework to do performance measurements for hidden service. I'm looking to get some feedback on the whole idea, improvement and help on possible analysis. If this work is not thrown out the window, I'll definitely do a Wiki page for a detail documentation but for now this is still a bit too early I think. *** PLEASE NOTE THAT THIS FRAMEWORK IS _NOT_ INTENDED TO BE USED ON THE REAL TOR NETWORK, ONLY TEST NETWORK! *** (I'll even add a check to make sure TestingTorNetwork is set to 1 else tor should not run.) The whole idea of this effort is to have a way to do very precise measurements of hidden service so we can come up with a performance baseline and have a reliable way to measure our progress on improving HS. We want to run this on large private network such as Shadow in order to get a better understanding of this whole HS subsystem. Finally, this can be extended to all sorts of component in tor in the future to help us analyze the beast that tor has become. :) This work uses tracing[0] for measurements. For that, I've instrumented the Tor code base with "tracepoints" that allows us to hook a tracer to those so we can collect data and do analysis afterward. The following branch contains a bunch of tracepoints mostly for HS and uses the LTTng[1] user space tracer. It's based on tor 0.2.5 version because we wanted to measure regression or improvement between 0.2.5 and upcoming 0.2.6 (especially with Andrea's new scheduler work). https://gitweb.torproject.org/user/dgoulet/tor.git [branch: hs-lttng-025] To compile this branch you need to install lttng-ust (tracer). It's pretty easy to install, you can find out how here[2]. (You will need version 2.4.0 or above). ./configure --enable-lttng-tracing In "src/or/trace/events.h", you can find all tracepoints that have been added with the data they collect. It is a bit too tidious to explain them all to you in this email but every "tor_trace_*" line is a tracepoint that you can grep in the code to see their location thus have a clearer picture of what they record. First, if you see any tracepoints that record something but are not at the right place in the code, you should definitely let me know. Second, telling me where tracepoint should be added also is very useful! No need to understand the full tracing system, just "that function should have a tracepoint to record this", I'll do the rest. Now to use tracing with Tor and analyze the data, you can find useful information and examples in this repository. (Pretty sure it's missing some documentation so please point it out!) https://gitorious.org/tor-hs-stats/tor-hs-stats Here are examples of graph that we can do with the collected data from the traces. (Introcuction Points Ready Time) https://people.torproject.org/~dgoulet/hs/ip-025.png or (Rendezvous Point Ready Time) https://people.torproject.org/~dgoulet/hs/rp-025.png Now to make analysis, I've build what is called in the tracing world a "state system". See that as a way to represent different objects in an application that are populated by the data that has been collected with tracing (trace). For this, please take a look at "lttng-analyze.py" in the gitorious repository. That script parses the trace event by event (event is what a tracepoint generated), populates the state system which is analyzed after the trace is fully parsed. It's pretty straight forward and here is the power of the state system. Once build from a trace, we can run *ALL* sorts of analysis on it to measure timings, find bad behaviors, etc.. If that interests you, I encourage you to play with all this and see for yourself what can be achieved thus opening your eyes on the possibilities. :) Ok, so there is a lot to explain to make things clear. I'm pretty sure I'm forgetting some here. Understanding the benifits of tracing is not that trivial at first glance so I'll be really happy to explain it to anyone asking. Any feedback is positive feedback! I'm happy to answer any questions. I'll most probably follow up this with a post about some results at some point. Cheers! David [0] https://en.wikipedia.org/wiki/Tracing_%28software%29 [1] https://lttng.org [2] https://lttng.org/download/

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Regarding involvement in organisation project for GSOC 2015
by dp docs 19 Dec '14

19 Dec '14

Dear Sir, I am a research student. I have good skills in languages c/c++,python. I want to participate in GSOC 2015 by taking a project from your organisation. please help me how should I start so that i will surely be able to participate in GSOC 2015 from your organisation. Please provide the mentor's email id so that I can contact them. It would be very much helpful for me if you are responding this mail. Moreover,i have tried to connect to #tor-dev IRC channel but it was showing that "you are banned". please help regaridng this too. please respond ASAP so that I can start working in a significant way. Thanks Durgesh Pandey.

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Suggestions for Projects
by Abhiram Chintangal 18 Dec '14

18 Dec '14

Hello, I am a student and I am thinking of getting myself more involved in the tor project over the winter break. Previously, I worked briefly on the tor-weather rewrite project which eventually turned into an gsoc project in March 2014. Are there any projects that are in need of a volunteer? I am well versed in C, Python and Java (Android). Cheers! -- Abhiram Chintangal

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basket: More eggs in the Guard basket.
by Yawning Angel 17 Dec '14

17 Dec '14

Hi all, For several reasons I've been working on a bit of code that I named "basket". It's almost at the point where the brave members of the general public should be aware that it exists as a potential option in the privacy toolbox, though using it in any capacity beyond testing on a loopback device IS CURRENTLY ACTIVELY DISCOURAGED unless users are comfortable debugging it (This means, DO NOT USE IT. I will likely break backward compatibility in the future, and you will be sad.). "basket" is my stab at designing something that significantly increases Tor's resistance to upcoming/future attacks, by providing a link layer cryptographic handshake that uses post-quantum cryptographic primitives and defenses against website fingerprinting (and possibly e2e correlation) attacks. For the ease of development it is in the form of a pluggable transport with the expected tradeoffs (you must absolutely trust your Bridge, since both features only run to the Bridge). It is worth noting that it is anything but subtle, and it is blatantly obvious that a given connection is speaking "basket" as no attempt was made to obfuscate the handshake. The link layer handshake works roughly like thus: Setup: * Bob generates a long term SPHINCS256 keypair s,S used to sign responses. The handshake: 1. Alice generates a Curve25519 keypair x,X and a NTRUEncrypt EES1171EP1 keypair n,N. 2. Alice sends X | N to Bob. 3. Bob generates a Curve25519 keypair y,Y, and calculates Curve25519(y,X) as the shared secret. 4. Bob sends NTRUEncrypt(N,Y) | S | SPHINCS256(s, ntru_ciphertext | S) to Alice. 5. Alice verifies the SPHINCS256 signature (Alice's copy of S is saved/trusted in a Trust-On-First-Use manner), and decrypts the NTRU ciphertext to obtain Y. 6. Alice calculates Curve25519(x,Y) as the shared secret. NB: Some details omitted for brevity. Passive attackers see Alice's Curve25519 public key, Alice's NTRUEncrypt public key, Bob's SPHINCS256 public key, a NTRUEncrypt ciphertext, and SPHINCS256 signature. Obtaining the link's ephemeral session key requires decrypting the NTRUEncrypt ciphertext (to obtain Bob's Curve25519 public key), and reversing the scalar base multiply on one of X and Y. Active man-in-the-middle attackers need to be able to forge SPHINCS256 signatures to substitute their own NTRUEncrypt-ed payload to mount an attack (Alice's request is also validated/protected but it's one of the details omitted, read the code). As NTRUEncrypt is patent encumbered, there also is a handshake mode that removes the experimental post-quantum cryptography and uses Ed25519/Curve25519. The fingerprinting defenses are in the form of the CS-BuFLO algorithm in CTST (Client total, Server total) mode, without the application level hinting based optimizations to reduce bandwidth consumption (See: http://www3.cs.stonybrook.edu/~rob/papers/csbuflo.pdf). As a minor implementation refinement, "basket" uses the kernel information as described in the KIST paper to be more responsive to changing network conditions. Most of the CS-BuFLO parameters were adjusted in an attempt to compensate for the lack of said application level hinting, but "basket"'s CS-BuFLO implementation is still a lot more expensive than the one presented in the paper. The code: http://github.com/yawning/basket Notes: * The PQ crypto primitives used are ports to Go by yours truly based on the reference implementations. It is both possible and likely that I messed something up, so users should decide between trusting my implementations and using a handshake based on classical algorithms. * The "basket" handshake consumes a non-trivial amount of CPU on the server side due to the SPHINCS256 implementation being relatively unoptimized. * CS-BuFLO is EXTREMELY BANDWIDTH INTENSIVE, and if adversaries can observe the Bridge's upstream, it likely can be broken, especially if the Bridge is only servicing a handful of users. Running the defense end-to-end (or even to the middle relay) is *extremely* non-trivial, though that would be required if something more comprehensive is desired. * The KIST code is platform specific, and I only wrote the Linux version. If this ends up being useful to people, support for other platforms is possible. * "basket" was never written to be a general use transport, though it sits somewhere between obfsproxy-wfpadtools (a pure research framework) and obfs4proxy (something that is intended to be used in production) in terms of completeness. Thanks to Marc Juarez (KU Leuven) and Mike Perry for inspiration to write the CS-BuFLO component of "basket". Questions, comments, feedback appreciated as always, -- Yawning Angel ps: Seriously, unless you are a developer or researcher, you REALLY SHOULD NOT use "basket".

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TOR C# application
by Hollow Quincy 17 Dec '14

17 Dec '14

Hi all, I would like to write a C# application (IRC client) that is using TOR. I read a lot, but I still don't know how can I run TOR proxy in transparent way (from my c# code). I see that Tor Stem (https://stem.torproject.org/) can be used by Python code or there are packages for Linux, but not C# (.NET). How can I run Tor proxy from C# ? Is there a library (dll) that I can run ? (without need to have open Tor Bundle browser). Thanks for help

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TOR C# application
by Hollow Quincy 16 Dec '14

16 Dec '14

[...] > install TOR client(Not Browser Bundle) and run it. Then socks port will > open and you can connect from your program through TCP. Could you please answer me more clearly ? I read description of all TOR projects: https://www.torproject.org/projects/projects "Stem" project looks nice for me, but it is in python. I would like something in C#, dll library or command line tool. But there is no "TOR client" project.. What do you mean by "TOR client" ?

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Pluggable transports meeting tomorrow (16:00UTC Wednesday 17th of December 2014)
by Yawning Angel 16 Dec '14

16 Dec '14

Hello! Just wanted to remind you that the regular biweekly pluggable transports meeting is going to occur tomorrow at 16:00 UTC. Place is the #tor-dev IRC channel in the OFTC network. Thanks for your attention! -- Yawning Angel

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TOR C# application
by Hollow Quincy 16 Dec '14

16 Dec '14

>> Hi all, >> >> I would like to write a C# application (IRC client) that is using TOR. >> I read a lot, but I still don't know how can I run TOR proxy in >> transparent way (from my c# code). >> >> I see that Tor Stem (https://stem.torproject.org/) can be used by >> Python code or there are packages for Linux, but not C# (.NET). >> >> How can I run Tor proxy from C# ? Is there a library (dll) that I can >> run ? (without need to have open Tor Bundle browser). > >Let your application start a 'private' Tor node and connect your program >using SOCKS to it. Could you please give me a hint how to do that ? Should I use some library ? or can I find it in Tor Browser Bundle ? (Remember that I would like to do it in background) Thanks for help

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Tor bridge reachability timeline being updated?
by David Fifield 16 Dec '14

16 Dec '14

Arturo, I really like http://reports.ooni.nu/analytics/bridge_reachability/timeline/. Is it still being updated? Are updates going to a different place? What does it take to add obfs4 support? As obfs4 is about to be introduced, it would be great to have reachability measurements from a variety of vantage points from the very beginning. David Fifield

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A Tor document parser implemented in Go
by Philipp Winter 16 Dec '14

16 Dec '14

I have started working on a project to detect sybils and other anomalies in the Tor network. Once the algorithms are implemented, I want to run them over historical data. While Stem is great, it's implemented in an interpreted language which makes it a little bit too slow for my needs. As a result, I started working on a simple parser implemented in Go: <https://gitweb.torproject.org/user/phw/zoossh.git/> Here's a mirror on GitHub: <https://github.com/NullHypothesis/zoossh> At the moment, the parser partially supports historical network consensuses and router descriptors as archived by CollecTor. I hope to be able to add more file formats soon. Also, the API is not yet stable, so it's not wise to use it just yet. However, I wanted folks to know that I'm working on that and I'm always happy to get feedback and patches. Cheers, Philipp

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