Introduction to algorithms
CRYPTO '93 Proceedings of the 13th annual international cryptology conference on Advances in cryptology
Randomized Distributed Edge Coloring via an Extension of the Chernoff--Hoeffding Bounds
SIAM Journal on Computing
Iolus: a framework for scalable secure multicasting
SIGCOMM '97 Proceedings of the ACM SIGCOMM '97 conference on Applications, technologies, architectures, and protocols for computer communication
Secure group communications using key graphs
Proceedings of the ACM SIGCOMM '98 conference on Applications, technologies, architectures, and protocols for computer communication
Key management for restricted multicast using broadcast encryption
IEEE/ACM Transactions on Networking (TON)
Simple and fault-tolerant key agreement for dynamic collaborative groups
Proceedings of the 7th ACM conference on Computer and communications security
Integer Sorting in 0(n sqrt (log log n)) Expected Time and Linear Space
FOCS '02 Proceedings of the 43rd Symposium on Foundations of Computer Science
Light Weight Broadcast Exclusion Using Secret Sharing
ACISP '00 Proceedings of the 5th Australasian Conference on Information Security and Privacy
An Information Theoretic Analysis of Rooted-Tree Based Secure Multicast Key Distribution Schemes
CRYPTO '99 Proceedings of the 19th Annual International Cryptology Conference on Advances in Cryptology
Coding Constructions for Blacklisting Problems without Computational Assumptions
CRYPTO '99 Proceedings of the 19th Annual International Cryptology Conference on Advances in Cryptology
Revocation and Tracing Schemes for Stateless Receivers
CRYPTO '01 Proceedings of the 21st Annual International Cryptology Conference on Advances in Cryptology
The LSD Broadcast Encryption Scheme
CRYPTO '02 Proceedings of the 22nd Annual International Cryptology Conference on Advances in Cryptology
Fast Digital Identity Revocation (Extended Abstract)
CRYPTO '98 Proceedings of the 18th Annual International Cryptology Conference on Advances in Cryptology
A Quick Group Key Distribution Scheme with "Entity Revocation"
ASIACRYPT '99 Proceedings of the International Conference on the Theory and Applications of Cryptology and Information Security: Advances in Cryptology
A Revocation Scheme with Minimal Storage at Receivers
ASIACRYPT '02 Proceedings of the 8th International Conference on the Theory and Application of Cryptology and Information Security: Advances in Cryptology
Deterministic sorting in O(nlog logn) time and linear space
Journal of Algorithms
EUROCRYPT'91 Proceedings of the 10th annual international conference on Theory and application of cryptographic techniques
Efficient communication-storage tradeoffs for multicast encryption
EUROCRYPT'99 Proceedings of the 17th international conference on Theory and application of cryptographic techniques
All-pairs shortest paths with real weights in O(n3/ log n) time
WADS'05 Proceedings of the 9th international conference on Algorithms and Data Structures
Optimal subset-difference broadcast encryption with free riders
Information Sciences: an International Journal
Efficient broadcast encryption with user profiles
Information Sciences: an International Journal
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We provide algorithms to solve the free riders problem in broadcast encryption. In this problem, the broadcast server is allowed to choose some small subset F of the revoked set R of users to allow to decrypt the broadcast, despite having been revoked. This may allow the server to significantly reduce network traffic while only allowing a small set of non-privileged users to decrypt the broadcast. Although there are worst-case instances of broadcast encryption schemes where the free riders problem is difficult to solve (or even approximate), we show that for many specific broadcast encryption schemes, there are efficient algorithms. In particular, for the complete subtree method [25] and some other schemes in the subset-cover framework, we show how to find the optimal assignment of free riders in O(|R||F|) time, which is independent of the total number of users. We also define an approximate version of this problem, and study specific distributions of R for which this relaxation yields even faster algorithms. Along the way we develop the first approximation algorithms for the following problem: given two integer sequences a1 ≥a2 ≥⋯≥an and b1 ≥b2 ≥⋯≥bn, output for all i, an integer j′ for which aj′ + b$_{i--{\it j}\prime}$ ≤(1+ε) min j (aj + b$_{i--{\it j}}$). We show that if the differences ai – ai+1, bi–bi+1 are bounded, then there is an O(n4/3/ε2/3)-time algorithm for this problem, improving upon the O(n2) time of the naive algorithm.