James Birkett

Learn More
We provide the first description of and security model for authenticated key exchange protocols with predicate-based authentication. In addition to the standard goal of session key security, our security model also provides for credential privacy: a participating party learns nothing more about the other party’s credentials than whether they satisfy the(More)
In this paper, we introduce a new primitive called identity-based encryption with wildcards, or WIBE for short. It allows a sender to encrypt messages to a whole range of receivers whose identities match a certain pattern. This pattern is defined through a sequence of fixed strings and wildcards, where any string can take the place of a wildcard in a(More)
We propose new instantiations of chosen-ciphertext secure identitybased encryption schemes with wildcards (WIBE). Our schemes outperform all existing alternatives in terms of efficiency as well as security. We achieve these results by extending the hybrid encryption (KEM–DEM) framework to the case of WIBE schemes. We propose and prove secure one generic(More)
We introduce a new simplified notion of plaintext awareness, which we term PA2I, and show that this is equivalent to the standard definition of PA2 plaintext awareness for encryption schemes that satisfy certain weak security and randomness requirements. We also show that PA2 plaintext awareness is equivalent to PA2+ plaintext awareness under similar(More)
Plaintext-aware encryption is a simple concept: a public-key encryption scheme is plaintext aware if no polynomial-time algorithm can create a ciphertext without “knowing” the underlying message. However, the formal definitions of plaintext awareness are complex. This paper analyses these formal security definitions and presents the only known viable(More)
Heterocyclic architectures offer powerful creative possibilities to a range of chemistry end-users. This is particularly true of heterocycles containing a high proportion of sp3-carbon atoms, which confer precise spatial definition upon chemical probes, drug substances, chiral monomers and the like. Nonetheless, simple catalytic routes to new heterocyclic(More)
We propose a hybrid (KEM/DEM) model for the recently proposed primitive of identity-based encryption with wildcards (WIBE), and confirm that the hybrid construction is secure. We also propose new chosenciphertext secure WIBE schemes that have somewhat more efficient security reductions and some performance benefits. Our first construction is a generic one(More)
High quality, high performance random number generators are a vital component in modern cryptographic systems. While traditional LFSR designs have some advantages they can only be operated in one mode, namely the generation of random numbers. We present the ESP-RNG, a new design that is additionally capable of executing in a powerful predictification mode.(More)
  • 1