ALPTEKİN KÜPÇÜ Assistant Professor of Computer Science and Engineering
Core Research Cryptography Security Privacy Application Areas Research Topics Cloud Computation Cloud Storage Peer-to-Peer Systems Electronic Cash Electronic ID Cards Password-based Authentication... 2013 Alptekin Küpçü - Koç University 2
Cloud Computation [BCEJKL08] Challenges: Outsource a job to a more powerful entity, or multiple small entities, and get correct results, without wasting own resources. Current Generation: Amazon Mechanical Turk, SETI@Home, etc. Job is not well-defined. Results can be faked. No provable guarantees. Techniques: Obje, görsel, tablo, grafik alanı Game Theory and Mechanism Design, augmented with cryptographic techniques to deal with Byzantine users. 2013 Alptekin Küpçü - Koç University 3
Next Gen Cloud Computation [BCEJKL08] Guaranteed high fraction of correct results, even in presence of malicious users. Malicious users cannot force the boss to perform tons of extra work. Obje, görsel, tablo, grafik alanı 2013 Alptekin Küpçü - Koç University 4
Next Gen Cloud Computation [BCEJKL08] Guaranteed high fraction of correct results, even in presence of malicious users. Malicious users cannot force the boss to perform tons of extra work. Obje, görsel, tablo, grafik alanı 2013 Alptekin Küpçü - Koç University 5
Next Gen Cloud Computation [BCEJKL08] Guaranteed high fraction of correct results, even in presence of malicious users. Malicious users cannot force the boss to perform tons of extra work. reward fine Obje, görsel, tablo, grafik alanı 2013 Alptekin Küpçü - Koç University 6
Next Gen Cloud Computation [BCEJKL08] Guaranteed high fraction of correct results, even in presence of malicious users. Malicious users cannot force the boss to perform tons of extra work. reward fine Obje, görsel, tablo, grafik alanı 2013 Alptekin Küpçü - Koç University 7
Next Gen Cloud Computation [BCEJKL08] Guaranteed high fraction of correct results, even in presence of malicious users. Malicious users cannot force the boss to perform tons of extra work. reward fine Obje, görsel, tablo, grafik alanı 2013 Alptekin Küpçü - Koç University 8
Cloud Storage [EKPT09][K13][EK13][CKW13] Challenges: Outsource storage of data to a more powerful entity, or multiple small entities, while data will be kept intact, or you will get compensated. Current Generation: Amazon S3, Google Drive, Dropbox, etc. No guarantee that file will be kept intact. No service warranty. Techniques: Obje, görsel, tablo, grafik alanı Cryptography, as well as secure protocol design, probability, and errorcorrecting codes (erasure codes). 2013 Alptekin Küpçü - Koç University 9
Next Gen Cloud Storage [EKPT09][CKW13] [EK13a] Guaranteed high probability detection of integrity loss of data. 2013 Alptekin Küpçü - Koç University 10
Next Gen Cloud Storage [EKPT09][CKW13] [EK13a] Guaranteed high probability detection of integrity loss of data. 2013 Alptekin Küpçü - Koç University 11
Next Gen Cloud Storage [K13a] Automated official arbitration system with compensation (via e-cash). 2013 Alptekin Küpçü - Koç University 12
Next Gen Cloud Database [EK13b] Guaranteed verification of correctness, completeness, and freshness of query results. 2013 Alptekin Küpçü - Koç University 13
Next Gen Cloud Database [EK13b] Guaranteed verification of correctness, completeness, and freshness of query results. 2013 Alptekin Küpçü - Koç University 14
Peer-to-Peer Systems [BCEJKLR07][KL09][KL10a][KL10b][KL12] Challenges: Incentivize peers to contribute to the system, thereby increasing overall system performance and fault tolerance. Techniques: Cryptography (fair exchange protocols and electronic cash), together with economic analysis and game-theoretic models. Obje, görsel, tablo, grafik alanı Forced fair contribution by peers both increase the fault tolerance of the system, as well as increased performance. 2013 Alptekin Küpçü - Koç University 15
Electronic Cash [BCEJKLR07][MEKHL10] Applications: Electronic commerce, privacy-protecting protocols, anonymous credentials and electronic identity cards. Use Cases: Cryptographic protocol design, virtual economies, automated payments, and even official arbitration mechanisms. Future Uses: Obje, görsel, tablo, grafik alanı Accountability issues can be handled through e-cash while preserving privacy (e.g., in GPS, transport, or cloud systems). 2013 Alptekin Küpçü - Koç University 16
Efficient Cryptography TOPIC RELATED WORK OUR WORK Cloud Storage network overhead N/A 10 KB Cloud Storage computation overhead N/A 1 ms Judge Arbitration network overhead 25 KB 80 bytes Judge Arbitration computation overhead 1 second 2 ms P2P Fairness network overhead (over 2.8 GB) 225 MB 1.8 MB P2P Fairness computation overhead (over 1.5 hours) 42 minutes 40 seconds 2-3 orders of magnitude 2013 Alptekin Küpçü - Koç University 17
Collaboration Areas Outsourced Databases Privacy (e.g., PIR, obfuscation) Usable Security Password-based Authentication and OTP Peer-to-Peer Systems Fair (video) streaming, P2P storage Anonymous Credentials (and E-cash) Electronic ID and Passport Electronic Health Privacy-preserving Information Sharing Internet Security FIA, LTE, mobile ad-hoc network security 2013 Alptekin Küpçü - Koç University 18
IC1206 Related Reversible De-Identification Replace identifier with encrypted version Protect integrity of the whole object, not just the identifier Reversing possible only with multiple authorities joint effort Multi-biometric encryption Fuzzy extractors Encryption that can be opened using alternative keys derived from different biometrics 2013 Alptekin Küpçü - Koç University 19
ALPTEKİN KÜPÇÜ Assistant Professor of Computer Science and Engineering http://crypto.ku.edu.tr
References [BCEJKLR07] Mira Belenkiy, Melissa Chase, Chris Erway, John Jannotti, Alptekin Küpçü, Anna Lysyanskaya, and Eric Rachlin. Making P2P Accountable without Losing Privacy. ACM WPES of ACM CCS, 2007. [BCEJKL08] Mira Belenkiy, Melissa Chase, Chris Erway, John Jannotti, Alptekin Küpçü, and Anna Lysyanskaya. Incentivizing outsourced computation. NetEcon of ACM SIGCOMM, 2008. [KL09] Alptekin Küpçü and Anna Lysyanskaya. Brief Announcement: Impossibility Results on Optimistic Fair Exchange with Multiple Autonomous Arbiters. PODC 2009. [EKPT09] Chris Erway, Alptekin Küpçü, Charalampos Papamanthou, and Roberto Tamassia. Dynamic Provable Data Possession. ACM CCS 2009. [KL10a] Alptekin Küpçü and Anna Lysyanskaya. Usable Optimistic Fair Exchange. CT-RSA 2010. [KL10b] Alptekin Küpçü and Anna Lysyanskaya. Optimistic Fair Exchange with Multiple Arbiters. ESORICS, 2010. [MEKHL10] Sarah Meiklejohn, Chris Erway, Alptekin Küpçü, Theodora Hinkle, and Anna Lysyanskaya. Enabling Efficient Implementation of Zero-Knowledge Proofs and Electronic Cash with ZKPDL. USENIX Security, 2010. [K10] Alptekin Küpçü. Efficient Cryptography for the Next Generation Secure Cloud: Protocols, Proofs, and Implementation. Lambert Academic Publishing, 2010. [CKO11] Sena Efsun Cebeci, Alptekin Küpçü, Öznur Özkasap, Secure Peer-to-Peer Health Sharing. Turkish National Medical Informatics Congress, 2011. [KL12] Alptekin Küpçü and Anna Lysyanskaya. Usable Optimistic Fair Exchange. Elsevier Computer Networks Journal, 2012, 56(1), 50-63. [ABK13] Tolga Acar, Mira Belenkiy, and Alptekin Küpçü. Single Password Authentication. Elsevier Computer Networks Journal, 2013, 57(13), 2597-2614. [KEKO13] Ertem Esiner, Adilet Kachkeev, Alptekin Küpçü, Öznur Özkasap. Energy Efficiency in Secure and Dynamic Cloud Storage. EE-LSDS, 2013. [EK13a] Mohammad Etemad and Alptekin Küpçü. Transparent, Distributed, and Replicated Dynamic Provable Data Possession. ACNS, 2013. [EK13b] Mohammad Etemad and Alptekin Küpçü. Database Outsourcing with Hierarchical Authenticated Data Structures. ICICS, 2013. [CKW13] David Cash, Alptekin Küpçü, and Daniel Wichs. Dynamic Proofs of Retrievability via Oblivious RAM. EUROCRYPT, 2013. [K13a] Alptekin Küpçü. Official Arbitration and its Application to Secure Cloud Storage. The Computer Journal, 2013. [K13b] Alptekin Küpçü. Distributing Trusted Third Parties. ACM Sigact News Distributed Computing Column, 2013, 44(2), 88-118. [K13c] Alptekin Küpçü. Efficient Cryptography for the Next Generation Secure Cloud. IEEE Computing Now, March 8, 2013.