References of "Pustogarov, Ivan 50002894"
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See detailProof-of-Work as Anonymous Micropayment: Rewarding a Tor Relay
Biryukov, Alex UL; Pustogarov, Ivan UL

in Financial Cryptography and Data Security - 19th International Conference (2015, January)

In this paper we propose a new micropayments scheme which can be used to reward Tor relay operators. Tor clients do not pay Tor relays with electronic cash directly but submit proof of work shares which ... [more ▼]

In this paper we propose a new micropayments scheme which can be used to reward Tor relay operators. Tor clients do not pay Tor relays with electronic cash directly but submit proof of work shares which the relays can resubmit to a crypto-currency mining pool. Relays credit users who submit shares with tickets that can later be used to purchase improved service. Both shares and tickets when sent over Tor circuits are anonymous. The analysis of the crypto-currencies market prices shows that the proposed scheme can compensate significant part of Tor relay operator's expenses. [less ▲]

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See detailBitcoin over Tor isn't a good idea
Biryukov, Alex UL; Pustogarov, Ivan UL

in 2015 IEEE Symposium on Security and Privacy (2014, November)

Bitcoin is a decentralized P2P digital currency in which coins are generated by a distributed set of miners and transaction are broadcasted via a peer-to-peer network. While Bitcoin provides some level of ... [more ▼]

Bitcoin is a decentralized P2P digital currency in which coins are generated by a distributed set of miners and transaction are broadcasted via a peer-to-peer network. While Bitcoin provides some level of anonymity (or rather pseudonymity) by encouraging the users to have any number of random-looking Bitcoin addresses, recent research shows that this level of anonymity is rather low. This encourages users to connect to the Bitcoin network through anonymizers like Tor and motivates development of default Tor functionality for popular mobile SPV clients. In this paper we show that combining Tor and Bitcoin creates an attack vector for the deterministic and stealthy man-in-the-middle attacks. A low-resource attacker can gain full control of information flows between all users who chose to use Bitcoin over Tor. In particular the attacker can link together user’s transactions regardless of pseudonyms used, control which Bitcoin blocks and transactions are relayed to the user and can delay or discard user’s transactions and blocks. In collusion with a powerful miner double-spending attacks become possible and a totally virtual Bitcoin reality can be created for such set of users. [less ▲]

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See detailDeanonymisation of clients in Bitcoin P2P network
Biryukov, Alex UL; Khovratovich, Dmitry UL; Pustogarov, Ivan UL

in ACM Conference on Computer and Communications Security (CCS) (2014, November)

Bitcoin is a digital currency which relies on a distributed set of miners to mint coins and on a peer-to-peer network to broadcast transactions. The identities of Bitcoin users are hidden behind ... [more ▼]

Bitcoin is a digital currency which relies on a distributed set of miners to mint coins and on a peer-to-peer network to broadcast transactions. The identities of Bitcoin users are hidden behind pseudonyms (public keys) which are recommended to be changed frequently in order to increase transaction unlinkability. We present an efficient method to deanonymize Bitcoin users, which allows to link user pseudonyms to the IP addresses where the transactions are generated. Our techniques work for the most common and the most challenging scenario when users are behind NATs or firewalls of their ISPs. They allow to link transactions of a user behind a NAT and to distinguish connections and transactions of different users behind the same NAT. We also show that a natural countermeasure of using Tor or other anonymity services can be cut-off by abusing anti-DoS countermeasures of the bitcoin network. Our attacks require only a few machines and have been experimentally verified. We propose several countermeasures to mitigate these new attacks. [less ▲]

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See detailContent and popularity analysis of Tor hidden services
Biryukov, Alex UL; Pustogarov, Ivan UL; Thill, Fabrice et al

in proceedings of the 2014 IEEE 34th International Conference on Distributed Computing Systems Workshops (2014, June)

Tor hidden services allow running Internet services while protecting the location of the servers. Their main purpose is to enable freedom of speech even in situations in which powerful adversaries try to ... [more ▼]

Tor hidden services allow running Internet services while protecting the location of the servers. Their main purpose is to enable freedom of speech even in situations in which powerful adversaries try to suppress it. However, providing location privacy and client anonymity also makes Tor hidden services an attractive platform for every kind of imaginable shady service. The ease with which Tor hidden services can be set up has spurred a huge growth of anonymously provided Internet services of both types. In this paper we analyse the landscape of Tor hidden services. We have studied 39824 hidden service descriptors collected on 4th of Feb 2013: we scanned them for open ports; in the case of 3050 HTTP services, we analysed and classified their content. We also estimated the popularity of hidden services by looking at the request rate for hidden service descriptors by clients. We found that while the content of Tor hidden services is rather varied, the most popular hidden services are related to botnets.We also propose a method for opportunistic deanonymisation of Tor Hidden Service clients. In addtiton, we identify past attempts to track “Silkroad” by consensus history analysis. [less ▲]

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See detailTrawling for tor hidden services: Detection, measurement, deanonymization
Biryukov, Alex UL; Pustogarov, Ivan UL; Weinmann, Ralf-Philipp UL

in 2013 IEEE Symposium on Security and Privacy (SP) (2013, May 19)

Tor is the most popular volunteer-based anonymity network consisting of over 3000 volunteer-operated relays. Apart from making connections to servers hard to trace to their origin it can also provide ... [more ▼]

Tor is the most popular volunteer-based anonymity network consisting of over 3000 volunteer-operated relays. Apart from making connections to servers hard to trace to their origin it can also provide receiver privacy for Internet services through a feature called "hidden services". In this paper we expose flaws both in the design and implementation of Tor's hidden services that allow an attacker to measure the popularity of arbitrary hidden services, take down hidden services and deanonymize hidden services. We give a practical evaluation of our techniques by studying: (1) a recent case of a botnet using Tor hidden services for command and control channels; (2) Silk Road, a hidden service used to sell drugs and other contraband; (3) the hidden service of the DuckDuckGo search engine. [less ▲]

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See detailTorScan: Tracing Long-Lived Connections and Differential Scanning Attacks
Biryukov, Alex UL; Pustogarov, Ivan UL; Weinmann, Ralf-Philipp UL

in Computer Security - ESORICS 2012 - 17th European Symposium on Research in Computer Security (2012)

Tor is a widely used anonymity network providing low-latency communication capabilities. The anonymity provided by Tor heavily relies on the hardness of linking a user’s entry and exit nodes. If an ... [more ▼]

Tor is a widely used anonymity network providing low-latency communication capabilities. The anonymity provided by Tor heavily relies on the hardness of linking a user’s entry and exit nodes. If an attacker gains access to the topological information about the Tor network instead of having to consider the network as a fully connected graph, this anonymity may be reduced. In fact, we have found ways to probe the connectivity of a Tor relay. We demonstrate how the resulting leakage of the Tor network topology can be used in attacks which trace back a user from an exit relay to a small set of potential entry nodes. [less ▲]

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See detailTorScan: Deanonymizing Connections Using Topology Leaks
Biryukov, Alex UL; Pustogarov, Ivan UL; Weinmann, Ralf-Philipp UL

in ERCIM News (2012), (90), 29-29

Tor is one of the most widely used tools for providing anonymity on the Internet. We have devised novel attacks against the Tor network that can compromise the anonymity of users accessing services that ... [more ▼]

Tor is one of the most widely used tools for providing anonymity on the Internet. We have devised novel attacks against the Tor network that can compromise the anonymity of users accessing services that exhibit frequent and predictable communication patterns and users establishing long-lived connections. [less ▲]

Detailed reference viewed: 156 (6 UL)