How to construct random functions
Journal of the ACM (JACM)
CRYPTO '93 Proceedings of the 13th annual international cryptology conference on Advances in cryptology
Pseudorandomness and Cryptographic Applications
Pseudorandomness and Cryptographic Applications
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
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
Efficient Trace and Revoke Schemes
FC '00 Proceedings of the 4th International Conference on Financial Cryptography
MARKS: Zero Side Effect Multicast Key Management Using Arbitrarily Revealed Key Sequences
NGC '99 Proceedings of the First International COST264 Workshop on Networked Group Communication
Key Establishment in Large Dynamic Groups Using One-Way Function Trees
IEEE Transactions on Software Engineering
Number-theoretic constructions of efficient pseudo-random functions
FOCS '97 Proceedings of the 38th Annual Symposium on Foundations of Computer Science
Digital Signatures for Flows and Multicasts
Digital Signatures for Flows and Multicasts
A Practical Revocation Scheme for Broadcast Encryption Using Smart Cards
SP '03 Proceedings of the 2003 IEEE Symposium on Security and Privacy
Digital rights management in a 3G mobile phone and beyond
Proceedings of the 3rd ACM workshop on Digital rights management
Efficient Time-Bound Hierarchical Key Assignment Scheme
IEEE Transactions on Knowledge and Data Engineering
A group key recovery mechanism based on logical key hierarchy
Journal of Computer Security
A practical revocation scheme for broadcast encryption using smartcards
ACM Transactions on Information and System Security (TISSEC)
Improved efficiency for revocation schemes via Newton interpolation
ACM Transactions on Information and System Security (TISSEC)
Birthday Paradox Based Security Analysis of Certain Broadcast Encryption Schemes
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences
Complexity comparison of Lagrange and Newton polynomial based revocation schemes
ECC'08 Proceedings of the 2nd conference on European computing conference
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Encryption is widely used to enforce usage rules for digital content. In many scenarios content is encrypted using a group key which is known to a group of users that are allowed to use the content. When users leave or join the group the group key must be changed. The LKH (Logical Key Hierarchy) algorithm is a very common method of managing these key changes. In this algorithm every user keeps a personal key composed of log n keys (for a group of n users). A key update message consists of O(log n) keys.A major drawback of the LKH algorithm is that users must update their state whenever users join or leave the group. When such an event happens a key update message is sent to all users. A user who is offline during t key updates, and which needs to learn the keys sent in these updates as well as update its personal key, should receive and process the t key update messages, of total length O(t log n) keys. In this paper we show how to reduce this overhead to a message of O(log t) keys. We also note that one of the methods that are used in this work to reduce the size of the update message can be used is other scenarios as well. It enables to generate n pseudo-random keys of length k bits each, such that any successive set of t keys can be represented by a string log(t) 驴 k bits, without disclosing any information about the other keys.