Progress in Cryptology - INDOCRYPT 2006

Volume 4329 of the series Lecture Notes in Computer Science pp 379-393

Secure Cryptographic Workflow in the Standard Model

  • M. BarbosaAffiliated withLancaster UniversityDepartamento de Informática, Universidade do Minho
  • , P. FarshimAffiliated withLancaster UniversityDepartment of Computer Science, University of Bristol

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Following the work of Al-Riyami et al. we define the notion of key encapsulation mechanism supporting cryptographic workflow (WF-KEM) and prove a KEM-DEM composition theorem which extends the notion of hybrid encryption to cryptographic workflow. We then generically construct a WF-KEM from an identity-based encryption (IBE) scheme and a secret sharing scheme. Chosen ciphertext security is achieved using one-time signatures. Adding a public-key encryption scheme we are able to modify the construction to obtain escrow-freeness. We prove all our constructions secure in the standard model.


Cryptographic Workflow Key Encapsulation Secret Sharing Identity-Based Encryption