2,449 research outputs found
Tor over QUIC
No full textTor is the most popular tool for anonymous online communication. However, the performance of Tor's volunteer-run network is suboptimal when network congestion occurs. Within Tor, many connections are multiplexed over a single TCP connection between relays, which causes a head-of-line blocking problem, degrading relay performance. In this thesis, Tor's TCP transport layer protocol is replaced by QUIC, a UDP-based protocol that natively supports multiplexing streams asynchronously, effectively solving head-of-line blocking. Its performance is evaluated within various network environments through Containernet, a flexible Docker-based network test bed that allows for simple reproduction of results. Along with testing multiple congestion control algorithms, the impact of using Hystart++ within Tor over QUIC is evaluated. It is found that QUIC over Tor can perform up to 50% better in time to last byte performance than vanilla Tor in a realistic network environment, while featuring more consistent time to first byte performance. Additionally, the evaluations shows that throughput consistency and fairness amongst downloaders are improved as well, Besides offering improved performance, Tor over QUIC is designed with deployability and security in mind. This makes QUIC an attractive replacement as Tor's transport layer protol.Computer Scienc
TOR Is required for the retrograde regulation of synaptic homeostasis at the drosophila neuromuscular junction
No full textHomeostatic mechanisms operate to stabilize synaptic function; however, we know little about how they are regulated. Exploiting Drosophila genetics, we have uncovered a critical role for the target of rapamycin (TOR) in the regulation of synaptic homeostasis at the Drosophila larval neuromuscular junction. Loss of postsynaptic TOR disrupts a retrograde compensatory enhancement in neurotransmitter release that is normally triggered by a reduction in postsynaptic glutamate receptor activity. Moreover, postsynaptic overexpression of TOR or a phosphomimetic form of S6 ribosomal protein kinase, a common target of TOR, can trigger a strong retrograde increase in neurotransmitter release. Interestingly, heterozygosity for eIF4E, a critical component of the cap-binding protein complex, blocks the retrograde signal in all these cases. Our findings suggest that cap-dependent translation under the control of TOR plays a critical role in establishing the activity dependent homeostatic response at the NMJ
Adding QUIC support to the Tor network
No full textPrivacy in the Internet is under attack by governments and companies indiscriminately spying on everyone. The anonymity network Tor is a solution to restore some privacy, however, Tor is slow in both bandwidth and latency. It uses a TCP-based connection to multiplex different circuits between nodes and this causes different independent circuits to interfere with each other. To solve this, we propose a transport layer implementation using the UDP-based protocol QUIC, as it allows independent streams over a single connection. We built a Tor prototype that uses this protocol and evaluated its performance using a custom network simulator, as existing simulators were shown to be incompatible. We show that the QUIC-based implementation increased performance in several of the use case scenarios, mainly outperforming on the ‘time to first byte’ metric.Electrical Engineering | Embedded System
Measuring accessibility of popular websites while using Tor
No full textTor is an anonymity network used by a vast number of users in order to protect their privacy on the internet. It should not come as a surprise that this service is also used for abuse such as Denial of service attacks and other malicious activities because of the anonymity it provides. For protecting themselves from this abuse, websites block Tor in various ways. We investigate the extent and frequency of this kind of blocking by requesting the Alexa top 1000 websites with and without Tor with the objective of highlighting the differential treatment observed by privacy-minded users. We build upon existing studies by using diverse metrics to measure discrimination and by extending our search to three sub pages of websites for detecting sophisticated blocking. We find at least 25.8% of the Alexa top 1000 websites discriminating on the home page against Tor users as opposed to 20.03% observed in previous studies. This number rises to 31.7% after including the three sub pages. We also discover new types of blocks such as Tor users being served old or different versions of websites. We categorize the blocked websites and find that Online Shopping and Finance/ Banking categories discriminate most against Tor while Social Networking sites and Search Engines discriminate the least.CSE3000 Research ProjectComputer Science and Engineerin
Products on Tor
Full text linkIn 1974 work establishing the collapse of certain Eilenberg-Moore spectral
sequences, Munkholm constructs, in passing, a bilinear multiplication operation
on Tor of a triple of -algebras. In 2020, the present author,
pursuing a multiplicative collapse result extending Munkholm's, studied a
variant of this product, without actually showing it agrees with Munkholm's. In
2019, Franz had defined a weak product on the two-sided bar construction of a
triple of -algebras under similar hypotheses, with which this author
proved a related collapse result, but without investigating the properties of
the induced product on Tor.
The present work demonstrates that the two products on Tor agree and are
induced by the product of Franz.Comment: 19 pages, comments welcom
Android Tor Tribler Tunneling (AT3): TI3800 Bachelorproject
No full textTribler is a decentralized peer-to-peer file sharing system. Recently the Tribler development team has introduced anonymous internet communication using a Tor-like protocol in their trial version. The goal of our bachelor project is to port this technology to Android devices. This is a challenging task because cross-compiling the necessary libraries to the ARM CPU architecture is uncharted territory. We have successfully ported all dependencies of Tribler to Android. An application called Android Tor Tribler Tunneling (AT3) has been developed that tests whether these libraries work. This application downloads a test torrent and measures information such as CPU usage and download speed. Based on this information we have concluded that it is currently not viable to run the anonymous tunnels on an Android smartphone. Creating circuits with several hops that use encryption is very computationally expensive and modern smartphones can hardly keep up. By using optimized cryptographic libraries such as gmp or with the recently announced ARMv8 architecture which supports hardware-accelerated AES encryption, creating such circuits might become possible.Tribler developmentParallel and Distributed Systems groupElectrical Engineering, Mathematics and Computer Scienc
Impact of replacing TCP by QUIC in Tor on website fingerprinting resistance
No full textPrivacy is a human right, yet, people’s behavior on the web is constantly tracked. Tor, an anonymity network, is an effective defence against tracking. However, Tor’s multiplexing of logically independent data streams into a single TCP connection causes issues. Tor with QUIC has been implemented as an alternative with better performance but it has not been studied whether and by how much QUIC increases the vulnerability to timing-based attacks.The most threatening attacks are website fingerprinting attacks, which can track a Tor user by only controlling the guard node, first of the relays that forward traffic in Tor. In this work, Tor with QUIC is evaluated against website fingerprinting attacks with various levels of defences active. Without defences, Tor is vulnerable to website fingerprinting for both TCP and QUIC but the attacks are more effective on QUIC. On the positive side, defences against website fingerprinting remain effective for QUIC in that they decrease the effectiveness of the attack by asimilar fraction as for TCP.Computer Science | Cyber Securit
Avoiding recording user activities: TOR, Linux Tails
No full textSieć TOR (The Onion Router) jest wirtualną siecią komputerową zapewniającą anonimizację oraz dostęp do często nielegalnych danych lub dla unikających cenzury. Linux Tails (The Amnesic Incognito Live System) stanowi natomiast system operacyjny bootowany wyłącznie z nośnika przenośnego (np.: pendrive, karty pamięci czy też płyty DVD) lub uruchamiany w sposób zwirtualizowany. Tails jako jedno z narzędzi oferuje dostęp do sieci TOR, zapewniając ponadto dalece wyszukane mechanizmy służące do unikania pozostawienia śladów cyfrowych na maszynie, z której korzysta użytkownik. Mimo innych intencji twórców obu omawianych powyżej narzędzi stały się one ulubionym pakietem olbrzymiej grupy przestępców na całym świecie. Autor w niniejszej publikacji skupia się na omówieniu zarówno obszarów powstawania śladów cyfrowych użytkowania TOR oraz Tails, jak i na możliwościach badawczych oraz możliwościach wnioskowania na ich podstawie. W pierwszej części artykułu opisany został mechanizm działania anonimizującej sieci TOR. Następnie autor zapoznaje czytelnika ze środowiskiem Linux Tails oraz odnosi się do faktycznych przypadków użycia.The Tor (The Onion Router) network is a virtual computer network that provides anonymisation and access to often illegal data or for those avoiding censorship. Linux Tails (The Amnesic Incognito Live System), on the other hand, is an operating system bootable only from a removable media (e.g.: flash drive, memory card or DVD) or run in a virtualized manner. Tails, as one of the tools, offers access to the Tor network providing, in addition, far sophisticated mechanisms to avoid leaving digital traces on the user’s machine. Despite the different intentions of the developers of the two tools discussed above, they have also become the favorite package of a huge group of criminals around the world. In this publication, the author focuses on discussing both the areas of formation of digital traces of Tor and Tails usage, as well as the research possibilities and inference possibilities based on them. The first part of the article describes the mechanism of the Tor anonymizing network. The author then introduces the reader to the Linux Tails environment and refers to actual use cases
Experimental characterization of viscoelastic behaviors, microstructure and thermal stability of CR/SBS modified asphalt with TOR
No full textIt is well known that crumb rubber (CR) and styrene–butadienestyrene (SBS) composite modified asphalt has better rheological and engineering performance. However, it always presents very poor compatibility and storage stability. Meanwhile, Trans-polyoctenamer (TOR) can effectively improve the compatibility and thermal stability of rubber asphalt. Thus, this study aims to investigate the effectiveness of TOR on rheological properties, microstructure and thermal stability of CR/SBS modified asphalt. The results show that TOR has a significant influence on strengthening anti-rutting and temperature sensitivity of CR/SBS modified asphalt. However, TOR has a slightly negative influence on the anti-cracking ability for CR/SBS modified asphalt, which still maintains the critical low temperature requirement. Furthermore, TOR could be able to promote the conformation of cross-linked structure between polymer and asphalt, resulting in a significant enhancement in rheological properties and thermal stability of CR/SBS modified asphalt. Lastly, the effects of TOR on viscoelastic performance for modified asphalt markedly depend on the component of neat asphalt, and high asphaltene content is beneficial for improving the rheological behavior effects of TOR.Pavement Engineerin
Measuring Polkadot: The Impact of Tor and a VPN on Polkadot's Performance and Security
No full textBegun in 2020, Polkadot is one of the largest blockchains in market capitalization and development. However, privacy on the Polkadot network has yet to be one of the key focus points. Especially unlinkability between the user’s IP address and Polkadot address is essential. Without this unlinkability, users are vulnerable to targeted ads, manipulation, blackmail, reputational damage, financial loss, physical harm, discrimination, and more. This thesis investigates the viability of Tor or a VPN with Polkadot as external privacy-enhancing tools to hide the user’s IP address, as users aiming to achieve unlinkability cannot easily change the Polkadot code.To analyze the viability, we set up a measurement study to examine the performance of a Polkadot full node behind Tor or a VPN. We investigated, among other things, the latency, throughput, and the number of discovered and connected peers to determine the performance of three Polkadot full nodes located in London, Seoul, and North California. Furthermore, we did a security analysis to determine any vulnerabilities that could emerge from using Polkadot with either of the network environments. And we investigated in-depth the susceptibility of the Polkadot node to an Eclipse attack, as previous research has shown that Bitcoin with Tor was vulnerable to an Eclipse attack.Our results show that a Polkadot node with Tor has considerably high latency and cannot maintain long-lasting connections. The short connection time decreases the time to perform an Eclipse attack on a Polkadot node from a couple of months and weeks for the normal and VPN environment to potentially six days or less for the Tor environment. We calculated the cost of running an Eclipse attack to be approximately €482 per week. The Polkadot node behind the VPN does perform considerably better. The Polkadot node in London, behind the VPN located in Frankfurt, performed similarly in terms of latency to the Polkadot node in a normal network environment. However, the Polkadot nodes in boththe Tor and VPN environment have only outgoing connections. If too many nodes ran behind one of these environments, fewer peers would be able to establish connections with one another, resulting in network partitions or network failure.This study emphasizes the importance of unlinkability between a Polkadot user’s address and IP. However, using Tor or a VPN as privacy-enhancing tools could impact the security of the Polkadot node and the whole Polkadot network. So users should avoid using Tor with Polkadot and carefully consider the tradeoff between privacy and security when using a VPN. The security issues mentioned in this thesis should be further investigated and tested. Furthermore, a default solution built into the Polkadot source code should be investigated.Computer Scienc
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