In spite of the vital role played by Digital Certificates in Public Key Cryptographic systems, the overhead involved in maintaining those made them prohibitory. Certificateless Public Key Cryptography [1] was proposed as an alternative. It was based on based on the concept of implicit certification. Even though Certificateless Public Key Cryptography (CLPKC) combines the appealing features of P...

Most recently, Lee B. et al proposed a key issuing protocol for ID-based cryptography to solve the key escrow problem. However in this letter, we show that a malicious key generation center (KGC) can successfully attack the protocol to obtain users’ private keys. This means that in the protocol, the key escrow problem isn’t really removed.

We describe new algorithms for performing scalar multiplication on supersingular elliptic curves in characteristic three. These curves can be used in pairing-based cryptography. Since in pairing-based protocols besides pairing computations also scalar multiplications are required, and the performance of the latter is not negligible, improving it is clearly important as well. The techniques pres...

In our proposed scheme, the participants are arranged in a hierarchical structure according to their position or rank and each first level participant as a parent node delegates his power to the lower level hierarchical group members. The group members help to reconstruct the secret shares of their parent nodes in their absence and the secret key is reconstructed even if at least one parent nod...

Novel idea of hierarchical visual cryptography is stated in this paper. The key concept of hierarchical visual cryptography is based upon visual cryptography. Visual cryptography encrypts secret information into two pieces called as shares. These two shares are stacked together by logical XOR operation to reveal the original secret. Hierarchical visual cryptography encrypts the secret in variou...

Identity-based cryptography has become extremely fashionable in the last few years. As a consequence many proposals for identitybased key establishment have emerged, the majority in the two party case. We survey the currently proposed protocols of this type, examining their security and efficiency. Problems with some published protocols are noted.

Cryptography based on lattices is the use of conjectured hard problems on point lattices in Rn as the basis for security in cryptosystems. In this report, firstly we introduce lattices and some hard problems based on lattice then present some of the major developments in lattice-based cryptography. The main focus in this report is on the fundamental learning with errors (LWE) problems, Ring-LWE...

In this paper we consider how practical interoperation between a conventional PKI and an infrastructure based on ID-based cryptography might be achieved. Major issues arising from such interoperation are raised, and possible solutions are proposed.

This paper describes an extremely efficient squaring operation in the so-called ‘cyclotomic subgroup’ of F× q6 , for q ≡ 1 mod 6. Our result arises from considering the Weil restriction of scalars of this group from Fq6 to Fq2 , and provides efficiency improvements for both pairingbased and torus-based cryptographic protocols. In particular we argue that such fields are ideally suited for the l...

For AES 128 security level there are several natural choices for pairing-friendly elliptic curves. In particular, as we will explain, one might choose curves with k = 9 or curves with k = 12. The case k = 9 has not been studied in the literature, and so it is not clear how efficiently pairings can be computed in that case. In this paper, we present efficient methods for the k = 9 case, includin...