Security weaknesses of certain broadcast encryption schemes

Abstract

This paper points out to a generic vulnerability of certain broadcast encryption schemes. This vulnerability can be effectively explored assuming chosen plaintext attacks, and in some cases even under ciphertext only attack. The developed methods for cryptanalysis are based on an attacking approach not taken into account in the security evaluations of the reported broadcast encryption schemes. The proposed attacks are based on employment of a dedicated time-data-memory trade-off approach for cryptanalysis. Two algorithms for cryptanalysis are proposed (both in the basic and the generalized versions) and their main characteristics regarding the complexity and required sample are pointed out. The algorithms are applied for cryptanalysis of particular recently reported broadcast encryption schemes implying that their security is far below the claimed ones.