Change search
Link to record
Permanent link

Direct link
BETA
Papadimitratos, PanagiotisORCID iD iconorcid.org/0000-0002-3267-5374
Alternative names
Publications (10 of 37) Show all publications
Barbette, T., Tang, C., Yao, H., Kostic, D., Maguire Jr., G. Q., Papadimitratos, P. & Chiesa, M. (2020). A High-Speed Load-Balancer Design with Guaranteed Per-Connection-Consistency. In: USENIX Association (Ed.), 17th USENIX Symposium on Networked Systems Design and Implementation: . Paper presented at NSDI'20 (pp. 667-683). Santa Clara, CA, USA
Open this publication in new window or tab >>A High-Speed Load-Balancer Design with Guaranteed Per-Connection-Consistency
Show others...
2020 (English)In: 17th USENIX Symposium on Networked Systems Design and Implementation / [ed] USENIX Association, Santa Clara, CA, USA, 2020, p. 667-683Conference paper, Published paper (Refereed)
Abstract [en]

Large service providers use load balancers to dispatch millions of incoming connections per second towards thousands of servers. There are two basic yet critical requirements for a load balancer: uniform load distribution of the incoming connections across the servers and per-connection-consistency (PCC), i.e., the ability to map packets belonging to the same connection to the same server even in the presence of changes in the number of active servers and load balancers. Yet, meeting both these requirements at the same time has been an elusive goal. Today's load balancers minimize PCC violations at the price of non-uniform load distribution.

This paper presents Cheetah, a load balancer that supports uniform load distribution and PCC while being scalable, memory efficient, resilient to clogging attacks, and fast at processing packets. The Cheetah LB design guarantees PCC for any realizable server selection load balancing mechanism and can be deployed in both a stateless and stateful manner, depending on the operational needs. We implemented Cheetah on both a software and a Tofino-based hardware switch. Our evaluation shows that a stateless version of Cheetah guarantees PCC, has negligible packet processing overheads, and can support load balancing mechanisms that reduce the flow completion time by a factor of 2–3×.

Place, publisher, year, edition, pages
Santa Clara, CA, USA: , 2020
Keywords
load-balancer, cheetah, high-speed, connection consistency, pcc, p4, fastclick
National Category
Communication Systems Computer Systems Computer Sciences
Research subject
Computer Science; Telecommunication
Identifiers
urn:nbn:se:kth:diva-268968 (URN)978-1-939133-13-7 (ISBN)
Conference
NSDI'20
Funder
Swedish Foundation for Strategic Research , TCCEU, European Research Council, 770889
Note

QC 20200302

Available from: 2020-03-01 Created: 2020-03-01 Last updated: 2020-03-02Bibliographically approved
Khodaei, M. & Papadimitratos, P. (2019). A Cooperative Location Privacy Protection Scheme for Vehicular Ad-hoc Networks. Stockholm, Sweden
Open this publication in new window or tab >>A Cooperative Location Privacy Protection Scheme for Vehicular Ad-hoc Networks
2019 (English)Report (Other academic)
Place, publisher, year, edition, pages
Stockholm, Sweden: , 2019. p. 1
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-253011 (URN)
Note

QC 20190611

Available from: 2019-06-11 Created: 2019-06-11 Last updated: 2019-06-11Bibliographically approved
Jin, H. & Papadimitratos, P. (2019). DoS-resilient cooperative beacon verification for vehicular communication systems. Ad hoc networks, 90, Article ID UNSP 101775.
Open this publication in new window or tab >>DoS-resilient cooperative beacon verification for vehicular communication systems
2019 (English)In: Ad hoc networks, ISSN 1570-8705, E-ISSN 1570-8713, Vol. 90, article id UNSP 101775Article in journal (Refereed) Published
Abstract [en]

Authenticated safety beacons in Vehicular Communication (VC) systems ensure awareness among neighboring vehicles. However, the verification of beacon signatures introduces significant processing overhead for resource-constrained vehicular On-Board Units (OBUs). Even worse in dense neighborhood or when a clogging Denial of Service (DoS) attack is mounted. The OBU would fail to verify for all received (authentic or fictitious) beacons. This could significantly delay the verifications of authentic beacons or even affect the awareness of neighboring vehicle status. In this paper, we propose an efficient cooperative beacon verification scheme leveraging efficient symmetric key based authentication on top of pseudonymous authentication (based on traditional public key cryptography), providing efficient discovery of authentic beacons among a pool of received authentic and fictitious beacons, and can significantly decrease waiting times of beacons in queue before their validations. We show with simulation results that our scheme can guarantee low waiting times for received beacons even in high neighbor density situations and under DoS attacks, under which a traditional scheme would not be workable. rights reserved.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2019
Keywords
Security, Privacy, Pseudonymous authentication, Efficiency
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:kth:diva-255177 (URN)10.1016/j.adhoc.2018.10.003 (DOI)000471740100005 ()2-s2.0-85055875023 (Scopus ID)
Note

QC 20190904

Available from: 2019-09-04 Created: 2019-09-04 Last updated: 2019-09-04Bibliographically approved
Ghasemi-Goojani, S. & Papadimitratos, P. (2019). On the Capacity of State-Dependent Gaussian Z-Interference Channel. In: Proceedings of 2018 International Symposium on Information Theory and Its Applications, ISITA 2018: . Paper presented at 15th International Symposium on Information Theory and Its Applications, ISITA 2018, 28 October 2018 through 31 October 2018 (pp. 653-657). Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>On the Capacity of State-Dependent Gaussian Z-Interference Channel
2019 (English)In: Proceedings of 2018 International Symposium on Information Theory and Its Applications, ISITA 2018, Institute of Electrical and Electronics Engineers Inc. , 2019, p. 653-657Conference paper, Published paper (Refereed)
Abstract [en]

We study the State-Dependent Gaussian Z-Interference Channel (SDG-ZIC), with two senders transmitting two independent messages through a Gaussian Z-interference channel with the same state. Transmitter 1 interferes with receiver 2, while transmitter 2 does not interfere with receiver 1. In addition, both receivers suffer from the same but differently scaled random state sequence, which is non-causally known at both transmitters. As mentioned in [1], the challenge here is to fully cancel differently scaled states at both receivers. Proposing transmission schemes based on nested lattice codes, we show that under some new conditions, the state at both receivers can be fully canceled and the capacity region can be fully achieved.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2019
Keywords
Gaussian distribution, Signal interference, Transmitters, Capacity regions, Gaussians, Interference channels, Nested lattice codes, Random state, State-dependent, Transmission schemes, Channel capacity
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-252221 (URN)10.23919/ISITA.2018.8664256 (DOI)000468678100134 ()2-s2.0-85063891075 (Scopus ID)9784885523182 (ISBN)
Conference
15th International Symposium on Information Theory and Its Applications, ISITA 2018, 28 October 2018 through 31 October 2018
Note

QC 20190611

Available from: 2019-06-11 Created: 2019-06-11 Last updated: 2019-08-02Bibliographically approved
Zhang, K. & Papadimitratos, P. (2019). On the Effects of Distance-decreasing Attacks on Cryptographically Protected GNSS Signals. In: Proceedings of the 2019 International Technical Meeting of The Institute of Navigation: . Paper presented at 2019 International Technical Meeting of The Institute of Navigation, January 28 - 31, 2019, Reston, Virginia (pp. 363-372).
Open this publication in new window or tab >>On the Effects of Distance-decreasing Attacks on Cryptographically Protected GNSS Signals
2019 (English)In: Proceedings of the 2019 International Technical Meeting of The Institute of Navigation, 2019, p. 363-372Conference paper, Published paper (Refereed)
Abstract [en]

The security of global navigation satellite systems draws attention increasingly, and authentication mechanisms for civilian services seem very effective in thwarting malicious behavior. For example, the Galileo E1 Open Service introduces navigation message authentication. Authentication, as well as encryption at navigation message or spreading code level, can prevent spoofing attacks, but do not preclude replay attacks. In this work, we consider a type of strong replay attacks, distance-decreasing attacks, against cryptographically protected GNSS signals. Distance-decreasing attack enhance an attacker’s capability of allowing it to mislead the victim receiver that the GNSS signals arrive earlier than true signals. We analyze the instantiation and the effects of the distance-decreasing attacks on unprotected GNSS signals, on navigation message authenticated signals, and on spreading-code encrypted signals. We discuss different strategies that the attacker can adopt to introduce the least bit errors to the re-transmitted signals and avoid being detected at the victim receiver. We provide evaluation results of distance-decreasing attacks on unprotected signals and authenticated navigation message signals, based on different strategies and configurations, and we sketch countermeasures to the different strategies.

Keywords
Distance-Decreasing (DD) attacks, Early Detection (ED), Late Commit (LC), Navigation Message Authentication (NMA), Spreading Code Encryption (SCE)
National Category
Engineering and Technology
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-248026 (URN)10.33012/2019.16736 (DOI)2-s2.0-85068322902 (Scopus ID)0-936406-21-6 (ISBN)
Conference
2019 International Technical Meeting of The Institute of Navigation, January 28 - 31, 2019, Reston, Virginia
Note

QC 20190412

Available from: 2019-04-02 Created: 2019-04-02 Last updated: 2020-03-05Bibliographically approved
Jin, H. & Papadimitratos, P. (2019). Resilient Privacy Protection for Location-Based Services through Decentralization. ACM Transactions on Privacy and Security (TOPS), 22(4), 1-36, Article ID 21.
Open this publication in new window or tab >>Resilient Privacy Protection for Location-Based Services through Decentralization
2019 (English)In: ACM Transactions on Privacy and Security (TOPS), ISSN 2471-2566, Vol. 22, no 4, p. 1-36, article id 21Article in journal (Refereed) Published
Abstract [en]

Location-Based Services (LBSs) provide valuable services, with convenient features for mobile users. However, the location and other information disclosed through each query to the LBS erodes user privacy. This is a concern especially because LBS providers can be honest-but-curious, collecting queries and tracking users’ whereabouts and infer sensitive user data. This motivated both centralized and decentralized location privacy protection schemes for LBSs: anonymizing and obfuscating LBS queries to not disclose exact information, while still getting useful responses. Decentralized schemes overcome disadvantages of centralized schemes, eliminating anonymizers, and enhancing users’ control over sensitive information. However, an insecure decentralized system could create serious risks beyond private information leakage. More so, attacking an improperly designed decentralized LBS privacy protection scheme could be an effective and low-cost step to breach user privacy. We address exactly this problem, by proposing security enhancements for mobile data sharing systems. We protect user privacy while preserving accountability of user activities, leveraging pseudonymous authentication with mainstream cryptography. We show our scheme can be deployed with off-the-shelf devices based on an experimental evaluation of an implementation in a static automotive testbed.

Place, publisher, year, edition, pages
ACM Press, 2019
Keywords
Location privacy, honest-but-curious, pseudonymous authentication
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-266759 (URN)10.1145/3319401 (DOI)000511381700002 ()2-s2.0-85073114023 (Scopus ID)
Note

QC 20200120

Available from: 2020-01-20 Created: 2020-01-20 Last updated: 2020-02-26Bibliographically approved
Zhang, K. & Papadimitratos, P. (2019). Safeguarding NMA Enhanced Galileo OS Signals from Distance-Decreasing Attacks. In: : . Paper presented at Proceedings of the 32nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2019) (pp. 4041-4052). Miami, Florida
Open this publication in new window or tab >>Safeguarding NMA Enhanced Galileo OS Signals from Distance-Decreasing Attacks
2019 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Increased use of global satellite navigation systems (GNSS), for applications such as autonomous vehicles, intelligent transportationsystems and drones, heightens security concerns. Civil GNSS signals are vulnerable to notably spoofing and replayattacks. To counter such attacks, cryptographic methods are developed: Navigation Message Authentication (NMA) is onesuch scheme, about to be deployed for Galileo E1 Open Service (OS); it allows receivers to verify the signal origin andprotects navigation message integrity. However, NMA signals cannot fully thwart replay attacks, which do not require forgingnavigation messages. Classic replay attacks, e.g, meaconing, retransmit previously recorded signals without any modification,thus highly limiting the capacity of the adversary. Distance-decreasing (DD) attacks are a strong type of replay attack,allowing fine-grained individual pseudorange manipulation in real time. Moreover, DD attacks counterbalance processing andtransmission delays induced by adversary, by virtue of shifting earlier in time the perceived (relayed) signal arrival; thusshortening the pseudorange measurements. In this paper, we first analyze how DD attacks can harm the Galileo E1 OSNMAservice assuming the adversary has no prior information on the navigation message. Moreover,we propose a DD attackdetection method based on a Goodness of Fit test on the prompt correlator outputs of the victim. The results show that themethod can detect the DD attacks even when the receiver has locked to the DD signals.

Place, publisher, year, edition, pages
Miami, Florida: , 2019
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-265517 (URN)2-s2.0-85075269802 (Scopus ID)
Conference
Proceedings of the 32nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2019)
Note

QC  20191212

Available from: 2019-12-12 Created: 2019-12-12 Last updated: 2020-02-04Bibliographically approved
Khodaei, M., Noroozi, H. & Papadimitratos, P. (2019). Scaling Pseudonymous Authentication for Large Mobile Systems. In: WiSec 2019 - Proceedings of the 2019 Conference on Security and Privacy in Wireless and Mobile Networks: . Paper presented at 12th Conference on Security and Privacy in Wireless and Mobile Networks, WiSec 2019; Miami; United States; 15 May 2019 through 17 May 2019 (pp. 174-185). Miami, FL, USA
Open this publication in new window or tab >>Scaling Pseudonymous Authentication for Large Mobile Systems
2019 (English)In: WiSec 2019 - Proceedings of the 2019 Conference on Security and Privacy in Wireless and Mobile Networks, Miami, FL, USA, 2019, p. 174-185Conference paper, Published paper (Refereed)
Abstract [en]

The central building block of secure and privacy-preserving Vehicular Communication (VC) systems is a Vehicular Public-Key Infrastructure (VPKI), which provides vehicles with multiple anonymized credentials, termed pseudonyms. These pseudonyms are used to ensure message authenticity and integrity while preserving vehicle (thus passenger) privacy. In the light of emerging large-scale multi-domain VC environments, the efficiency of the VPKI and, more broadly, its scalability are paramount. By the same token, preventing misuse of the credentials, in particular, Sybil-based misbehavior, and managing “honest-but-curious” insiders are other facets of a challenging problem. In this paper, we leverage the state-of-the-art VPKI system and enhance its functionality towards a highly-available, dynamically-scalable, and resilient design; this ensures that the system remains operational in the presence of benign failures or resource depletion attacks, and that it dynamically scales out, or possibly scales in, according to request arrival rates. Our full-blown implementation on the Google Cloud Platform shows that deploying large-scale and efficient VPKI can be cost-effective.

Place, publisher, year, edition, pages
Miami, FL, USA: , 2019
Keywords
VANETs, VPKI, Security, Privacy, Availability, Scalability, Resilient, Micro-service, Container Orchestration, Cloud.
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-253012 (URN)10.1145/3317549.3323410 (DOI)2-s2.0-85066733902 (Scopus ID)978-1-4503-6726-4 (ISBN)
Conference
12th Conference on Security and Privacy in Wireless and Mobile Networks, WiSec 2019; Miami; United States; 15 May 2019 through 17 May 2019
Note

QC 20190619

Available from: 2019-06-11 Created: 2019-06-11 Last updated: 2020-02-14Bibliographically approved
Wiese, M., Oechtering, T. J., Johansson, K. H., Papadimitratos, P., Sandberg, H. & Skoglund, M. (2019). Secure Estimation and Zero-Error Secrecy Capacity. IEEE Transactions on Automatic Control, 64(3), 1047-1062
Open this publication in new window or tab >>Secure Estimation and Zero-Error Secrecy Capacity
Show others...
2019 (English)In: IEEE Transactions on Automatic Control, ISSN 0018-9286, E-ISSN 1558-2523, Vol. 64, no 3, p. 1047-1062Article in journal (Refereed) Published
Abstract [en]

We study the problem of securely estimating the states of an unstable dynamical system subject to non-stochastic disturbances. The estimator obtains all its information through an uncertain channel, which is subject to nonstochastic disturbances as well, and an eavesdropper obtains a disturbed version of the channel inputs through a second uncertain channel. An encoder observes and block encodes the states in such a way that, upon sending the generated codeword, the estimator's error is bounded and a security criterion is satisfied, thereby ensuring that the eavesdropper obtains as little state information as possible. Two security criteria are considered and discussed with the help of a numerical example. A sufficient condition on the uncertain wiretap channel, i.e., the pair formed by the uncertain channel from the encoder to the estimator and the uncertain channel from the encoder to the eavesdropper is derived, which ensures that a bounded estimation error and security are achieved. This condition is also shown to be necessary for a subclass of uncertain wiretap channels. To formulate the condition, the zero-error secrecy capacity of uncertain wiretap channels is introduced, i.e., the maximal rate at which data can be transmitted from the encoder to the estimator in such a way that the eavesdropper is unable to reconstruct the transmitted data. Finally, the zero-error secrecy capacity of uncertain wiretap channels is studied.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019
Keywords
Secure state estimation, uncertain wiretap channel, zero-error secrecy capacity
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:kth:diva-247828 (URN)10.1109/TAC.2018.2849620 (DOI)000460415600012 ()2-s2.0-85048871914 (Scopus ID)
Note

QC 20190326

Available from: 2019-03-26 Created: 2019-03-26 Last updated: 2019-03-26Bibliographically approved
Ghasemi-Goojani, S. & Papadimitratos, P. (2019). The Symmetric Two-Hop Channel with an Untrusted Relay. In: Proceedings of 2018 International Symposium on Information Theory and Its Applications, ISITA 2018: . Paper presented at 15th International Symposium on Information Theory and Its Applications, ISITA 2018, 28 October 2018 through 31 October 2018 (pp. 673-677). Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>The Symmetric Two-Hop Channel with an Untrusted Relay
2019 (English)In: Proceedings of 2018 International Symposium on Information Theory and Its Applications, ISITA 2018, Institute of Electrical and Electronics Engineers Inc. , 2019, p. 673-677Conference paper, Published paper (Refereed)
Abstract [en]

We study, using information-theoretic security methods, the so-called symmetric two-hop channel with an untrusted relay. In this model, a source wants to send its message reliably and securely to the destination through an honest but curious relay. The relay acts as a passive eavesdropper. Our investigation, in line with the relevant literature, seeks to determine what rate, termed secrecy rate, is achievable. To do that, we consider a typical setting, with the destination cooperating with the source, sending a 'scrambling' signal to conceal the message from the relay. To derive the achievable secrecy rate, we propose a novel scheme based on nested lattice codes. We show that our scheme outperforms all existing schemes and it achieves the outer bound for this channel model within 0.33 bits.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2019
Keywords
Achievable secrecy rates, Channel model, Information- theoretic securities, Nested lattice codes, Outer bounds, Passive eavesdroppers, Untrusted relays, Information theory
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:kth:diva-252220 (URN)10.23919/ISITA.2018.8664257 (DOI)000468678100138 ()2-s2.0-85063910251 (Scopus ID)9784885523182 (ISBN)
Conference
15th International Symposium on Information Theory and Its Applications, ISITA 2018, 28 October 2018 through 31 October 2018
Note

QC 20190611

Available from: 2019-06-11 Created: 2019-06-11 Last updated: 2019-08-02Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-3267-5374

Search in DiVA

Show all publications