Philipp Winter

Philipp Winter

Postdoctoral Research Associate in Computer Science, Princeton University

I am interested in computer networks and security, and why the two don't get along very well. I enjoy being part of all phases of a research project—from sketching ideas on a whiteboard, to implementation, and finally deployment and maintenance. To this end, I have worked in the three research areas listed below. I keep maintaining code I have developed in these research projects, so they are open-ended in some sense.

Keeping bad actors out of the Tor network
As communities grow in size, it becomes increasingly hard to keep out bad actors, and Tor is no exception because the network is run by volunteers. In 2013, I started developing exitmap, a fast and flexible scanner for Tor exit relays. If you have a background in functional programming, think about it as a map() interface for Tor exit relays. It allows you to run arbitrary, TCP-based tests over each exit relay. One of the main tasks of exitmap is to expose and block malicious and misbehaving exit relays. I recently broadened my scope to Sybil relays, sets of Tor relays that are under the control of a single entity. I am developing sybilhunter which is meant to assist in finding and analysing Sybils.

Censorship analysis
Early on in my Ph.D. studies, I became interested in the Great Firewall of China (GFW). I was first exposed to the GFW in 2011, when trying to understand how it blocks the Tor network. I have since revisited the topic several times, to understand how the GFW fails over space and time, and how its active probing component is designed. As part of my work on the Tor network, I also helped characterise—and circumvent—a censorship system in Ethiopia.

Traffic obfuscation
Motivated by my work on censorship systems, I became interested in traffic obfuscation, i.e., shaping network traffic in a way that it is hard to classify and block. I started by developing a small tool for server-side circumvention. It was designed to prevent the GFW from recognising Tor handshakes on the wire. The tool transparently rewrites the window size in a SYN-ACK segment, forcing the client to split its initial payload across two segment instead of one. Back in 2012, the GFW would not reassemble TCP streams, rendering it unable to spot circumvention traffic “protected” by this tool. I then went on and developed ScrambleSuit, a polymorphic traffic obfuscation protocol. ScrambleSuit can protect against the GFW's active probing attacks by relying on a “password” that is shared between client and server. ScrambleSuit has since been superseded by the faster and more elegant obfs4, which is no longer maintained by me.

Tor upgrades to make anonymous publishing safer

Mar 20, 2017 01:56 am UTC| Technology

In the coming months, the Seattle-based nonprofit The Tor Project will be making some changes to improve how the Tor network protects users privacy and security. The free network lets users browse the internet anonymously....

Securing web browsing: protecting the Tor network

May 18, 2016 08:28 am UTC| Insights & Views Technology

There are more than 865 encryption tools in use worldwide, all addressing different aspects of a common problem. People want to protect information: hard drives from oppressive governments, physical location from stalkers,...



FxWirePro: The Day Ahead- 8th December 2017

Lots of economic data and events scheduled for today and some with high volatility risks associated. Data released so far: Australia: Hoe loans down 0.6 percent in October. Investment lending for homes grew 1.6...

FxWirePro: The Day Ahead- 7th December 2017

Lots of economic data and events scheduled for today and some with high volatility risks associated. Data released so far: Australia: October trade balance came at $105 million. Upcoming: Japan:...

U.S. Commerce department announces affirmative preliminary circumvention Rulings on Steel from Vietnam

Last night, U.S. Commerce Department announced preliminary affirmative circumvention rulings on steel imported from Vietnam accusing that corrosion-resistant steel (CORE) and certain cold-rolled steel flat products...

FxWirePro: The Day Ahead- 6TH December 2017

Lots of economic data and events scheduled for today and some with high volatility risks associated. Data released so far: Australia: Third-quarter GDP up 0.6 percent, up 2.8 percent from a year...

Norges Bank’s survey shows strong growth in mainland, growth likely to be higher in 2018

The Regional Network, Norges Banks business survey, shows strong growth in the Norwegian mainland economy. The Regional Network shows growth at 0.6 percent sequential in the last three months, consistent with Norges Banks...


Latino elites are paying the California dream forward

American Latino economic elites have incomes and wealth in the top 5 percent of earners. Some own multi-million-dollar companies or work as corporate executives. Latino politicians like Kevin De León, who is...

Brexit: why Macron has more room to manoeuvre than May and Merkel

Despite the valiant efforts of both the EU and the UK to uphold confidence in the Brexit negotiations process, its clear the talks have been deeply unsatisfactory for both sides. Fundamental conflicts of interest and...

Why PR agencies and their spin should be the subject of greater scrutiny

It was one of the biggest and best-known British PR agencies around. So when Bell Pottinger came crashing down earlier this year, you could be forgiven for wondering why it hadnt prepared a better crisis strategy to deal...

Catalonia crisis: Spain enters unchartered territory following Madrid move to end autonomy

Shortly after Catalonias parliament in Barcelona voted to declare independence from Spain on October 27, the senate in Madrid voted to trigger Article 155 of the Spanish constitution, removing Catalonias autonomy. In...

China's ambition burns bright - with Xi Jinping firmly in charge

The most important political event of 2017, the 19th Chinese Communist Party Congress, has concluded. And while there was much to digest, one image above all stands out: Xi Jinpings political dominance and his burning...


Scientists Prevent Weight Gain Despite High Fat Diet

The alarming rate of obesity and weight gain in industrialized nations is one of the most concerning health issues plaguing developed countries today. Scientists might have just come much closer to finally ending this...

Study Says Air Pollution Makes Exercise Pointless, Poses Huge Health Risks To Unborn Babies

Scientists have been encouraging older people to exercise in order to stay healthy, but according to a recent study, air pollution makes this rather pointless. Whats more, another study found that a dirty atmosphere has...

Baby Born Via Transplanted Uterus For The First Time

Further proving that advances in medical science never cease to amaze, a woman just gave birth to a baby with a transplanted uterus. This is the first time it has ever happened in the U.S. and provides hope to a lot of...

Smartphone Addiction Increases Anxiety And Depression, Study Finds

It might feel like the same old story, where elders take issue with new technology and tell the younger generation that their addiction to gadgets would result in problems. However, this time, tutting adults might have...

Thousands Of HIV Patients To Be Injected With HIV Vaccine In Human Trials

Even though HIV has been part of the human consciousness for several decades, creating a cure has proven difficult. Now, an international collaboration is about to perform human trials by injecting thousands of patients...


Far Cry 5 Delayed Due To Ubisoft’s Newfound Commitment To Quality

Ubisoft just announced that it will be delaying the release of several of its upcoming titles, including Far Cry 5 and the Crew 2. This is apparently due to the success of Assassins Creed Origins, which is currently being...

Net Neutrality Death May Or May Not Kill Bitcoin, Experts Disagree With Each Other

One of the biggest hot-button topics in the American political landscape right now is Net Neutrality and the upcoming vote by the Federal Communications Commission (FCC) to kill it. While many fear that the death of a free...

Vine Creator Teases New App, Could It Be Vine 2.0?

Reports that the creator of the previously popular app Vine was making a follow-up app started circulating recently when he revealed that he was working on a side project. Now, Dom Hofmann is teasing the internet with an...

Steam No Longer Accepts Bitcoin For Video Game Purchase

Even though Bitcoin is continuing to skyrocket in value, at least one prominent tech entity is jumping off the crypto bandwagon instead of on it. Valve just announced that it would no longer accept the digital currency on...

Accidental Leak Of God Of War March 2018 Release Date Might Have Been Intentional

Gamers recently spotted a release date on the PlayStation Stores God of War page. At the time, the page said that Kratos is coming back on March 22, 2018. The date has since been changed to December 31, 2018, but many are...
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