Return of the Boss Problem: Competing Online against a Non-adaptive Adversary

Author(s):  
Magnús M. Halldórsson ◽  
Hadas Shachnai
Keyword(s):  
2014 ◽  
Vol 543-547 ◽  
pp. 3300-3307 ◽  
Author(s):  
Xing Wen Zhao ◽  
Gao Fei Zhao ◽  
Hui Li

In broadcast encryption system certain users may leak their decryption keys to build pirate decoders, so traitor tracing is quite necessary. There exist many codes based traitor tracing schemes. As pointed out by Billet and Phan in ICITS 2008, these schemes lack revocation ability. The ability of revocation can disable identified malicious users and users who fail to fulfill the payments, so that the broadcast encryption system can be more practical. Recently, Zhao and Li presented a construction of codes based tracing and revoking scheme which achieves user revocation as well as traitor tracing. However, their scheme is only secure against chosen plaintext attacks under selective-adversary model with random oracle. In this paper, we obtain a new construction of codes based tracing and revoking scheme which is proved secure against chosen ciphertext attacks under adaptive-adversary model without random oracle. Our idea is to insert codeword into Boneh and Hamburgs identity based broadcast encryption scheme to retain the ability of user revocation and use Boneh and Naors method to trace traitors. Our fully secure scheme is roughly as efficient as Zhao and Lis scheme while the security is enhanced.


Author(s):  
Qingyu Guo ◽  
Bo An ◽  
Long Tran-Thanh

We study repeated network interdiction games with no prior knowledge of the adversary and the environment, which can model many real world network security domains. Existing works often require plenty of available information for the defender and neglect the frequent interactions between both players, which are unrealistic and impractical, and thus, are not suitable for our settings. As such, we provide the first defender strategy, that enjoys nice theoretical and practical performance guarantees, by applying the adversarial online learning approach. In particular, we model the repeated network interdiction game with no prior knowledge as an online linear optimization problem, for which a novel and efficient online learning algorithm, SBGA, is proposed, which exploits the unique semi-bandit feedback in network security domains. We prove that SBGA achieves sublinear regret against adaptive adversary, compared with both the best fixed strategy in hindsight and a near optimal adaptive strategy. Extensive experiments also show that SBGA significantly outperforms existing approaches with fast convergence rate.


Author(s):  
Ronald Cramer ◽  
Ivan Damgård ◽  
Stefan Dziembowski ◽  
Martin Hirt ◽  
Tal Rabin
Keyword(s):  

2007 ◽  
Vol 36 (585) ◽  
Author(s):  
Gerth Stølting Brodal ◽  
Rolf Fagerberg ◽  
Allan Grønlund Jørgensen ◽  
Gabriel Moruz ◽  
Thomas Mølhave

Abstract. In the resilient memory model any memory cell can get cor- rupted at any time, and corrupted cells cannot be distinguished from uncorrupted cells. An upper bound, , on the number of corruptions and O(1) reliable memory cells are provided. In this model, a data structure is denoted resilient if it gives the correct output on the set of uncor- rupted elements. We propose two optimal resilient static dictionaries, a randomized one and a deterministic one. The randomized dictionary supports searches in O(log n + ) expected time using O(log ) random bits in the worst case, under the assumption that corruptions are not performed by an adaptive adversary. The deterministic static dictionary supports searches in O(log n + ) time in the worst case. We also in- troduce a deterministic dynamic resilient dictionary supporting searches in O(log n + ) time in the worst case, which is optimal, and updates in O(log n + ) amortized time. Our dynamic dictionary supports range queries in O(log n + + k) worst case time, where k is the size of the output.


2000 ◽  
Vol 7 (6) ◽  
Author(s):  
Ivan B. Damgård ◽  
Jesper Buus Nielsen

Non-committing encryption enables the construction of multiparty computation protocols secure against an adaptive adversary in the computational setting where private channels between players are not assumed. While any non-committing encryption scheme must be secure in the ordinary semantic sense, the converse is not necessarily true. We propose a construction of non-committing encryption that can be based on any public key system which is secure in the ordinary sense and which has an extra property we call simulatability. The construction contains an earlier proposed scheme by Beaver based on the Die-Hellman problem as a special case, and we propose another implementation based on RSA. In a more general setting, our construction can be based on any collection of trapdoor one-way permutations<br />with a certain simulatability property. This offers a considerable efficiency<br />improvement over the first non-committing encryption scheme proposed by<br />Canetti et al. Finally, at some loss of efficiency, our scheme can be based on general collections of trapdoor one-way permutations without the simulatability assumption, and without the common domain assumption of Canetti et al.


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