Katerina Mitrokotsa
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Prof. Dr.
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Mitrokotsa
First name
Katerina
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katerina.mitrokotsa@unisg.ch
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+41 71 224 7861
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https://twitter.com/mitrokat
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  • Publication
    Two-hop Distance-Bounding Protocols: Keep your Friends Close.
    (IEEE, 2018-07-01)
    Yang, Anjia
    ;
    Pagnin, Elena
    ;
    Mitrokotsa, Aikaterini
    ;
    Hancke, Gerhard P.
    ;
    Wong, Duncan S.
    Type: journal article
    Journal: IEEE Transactions on Mobile Computing
    Volume: 17
    Issue: 7
    URL: https://ieeexplore.ieee.org/document/8103055
    DOI: 10.1109/TMC.2017.2771769
    URI: https://www.alexandria.unisg.ch/handle/20.500.14171/100253
    Scopus© Citations 19
  • Publication
    Practical & provably secure distance-bounding.
    (IOS Press, 2015)
    Boureanu, Ioana
    ;
    Mitrokotsa, Aikaterini
    ;
    Vaudenay, Serge
    From contactless payments to remote car unlocking, many applications are vulnerable to relay attacks. Distance bounding protocols are the main practical countermeasure against these attacks. In this paper, we present a formal analysis of SKI, which recently emerged as the first family of lightweight and provably secure distance bounding protocols. More precisely, we explicate a general formalism for distance-bounding protocols, which lead to this practical and provably secure class of protocols (and it could lead to others). We prove that SKI and its variants are provably secure, even under the real-life setting of noisy communications, against the main types of relay attacks: distance-fraud and generalised versions of mafia- and terrorist-fraud. To attain resistance to terrorist-fraud, we reinforce the idea of using secret sharing, combined with the new notion of a leakage scheme. In view of resistance to generalised mafia-frauds (and terrorist-frauds), we present the notion of circular-keying for pseudorandom functions (PRFs); this notion models the employment of a PRF, with possible linear reuse of the key. We also identify the need of PRF masking to fix common mistakes in existing security proofs/claims. Finally, we enhance our design to guarantee resistance to terrorist-fraud in the presence of noise.
    Type: journal article
    Journal: Journal of Computer Security
    Volume: 23
    Issue: 2
    URL: https://content.iospress.com/articles/journal-of-computer-security/jcs518
    DOI: 10.3233/JCS-140518
    URI: https://www.alexandria.unisg.ch/handle/20.500.14171/106980
    Scopus© Citations 30
  • Publication
    On selecting the nonce length in distance-bounding protocols.
    (Oxford University Press, 2013-04-04)
    Mitrokotsa, Aikaterini
    ;
    Peris-Lopez, Pedro
    ;
    Dimitrakakis, Christos
    ;
    Vaudenay, Serge
    Distance-bounding protocols form a family of challenge–response authentication protocols that have been introduced to thwart relay attacks. They enable a verifier to authenticate and to establish an upper bound on the physical distance to an untrusted prover. We provide a detailed security analysis of a family of such protocols. More precisely, we show that the secret key shared between the verifier and the prover can be leaked after a number of nonce repetitions. The leakage probability, while exponentially decreasing with the nonce length, is only weakly dependent on the key length. Our main contribution is a high probability bound on the number of sessions required for the attacker to discover the secret, and an experimental analysis of the attack under noisy conditions. Both of these show that the attack's success probability mainly depends on the length of the used nonces rather than the length of the shared secret key. The theoretical bound could be used by practitioners to appropriately select their security parameters. While longer nonces can guard against this type of attack, we provide a possible countermeasure which successfully combats these attacks even when short nonces are used.
    Type: journal article
    Journal: The Computer Journal
    Volume: 56
    Issue: 10
    DOI: 10.1093/comjnl/bxt033
    URI: https://www.alexandria.unisg.ch/handle/20.500.14171/89441
    Scopus© Citations 14