Ajtai and Dwork 2] have recently introduced a probabilistic public-key en-cryption scheme which is secure under the assumption that a certain computational problem on lattices is hard on the worst-case. Their encryption method may cause decrytion errors, though with small probability. Goldre-ich, Goldwasser, and Halevi 7] later modiied the encryption method of Ajtai and Dwork and made Ajtai-Dwo...

Popularity of group-oriented applications motivates research on security and privacy protection for group communications. A number of group key agreement protocols exploiting ID-based cryptosystem have been proposed for this objective. Though bearing beneficial features like reduced management cost, private key delegation from ID-based cryptosystem, they have not taken into account privacy issu...

As more sensitive data is shared and stored by third-party sites on the Internet, the data in these sites will need to encrypt. The main drawback of encrypting data is that it can be selectively shared only at a coarse-grained level (i.e., giving another party your private key). We progress a new cryptosystem for fine-grained sharing of reencrypted data that we call Key-Policy Attribute-Based E...

This paper presents a cost-effective private-key cryptosystem for color images. The scheme allows for secret sharing of the color image by generating two color shares with dimensions identical to those of the original. Encryption is performed via simple binary operations realized at the image bit-levels altering both the spectral correlation among the RGB color components and the spatial correl...

In this note we describe a variety of methods that may be used to increase the speed and efficiency of the NTRU public key cryptosystem. 1991 Mathematics Subject Classification: 94A60, 11T71. 1. An Overview of NTRU The NTRU Public Key Cryptosystem is based on ring theory and relies for its security on the difficulty of solving certain lattice problems. In this section we will briefly review the...

In this paper we provide a quantum public-key cryptosystem using non-orthogonal states. A user Alice uses a set of particles which are in non-orthogonal quantum states as the public key kept by a key management center (KMC) while she keeps the states of the particles secret as the private key. By the help of KMC any other user can send encrypted message to Alice. Any one including KMC except Al...

We present a new private information retrieval (PIR) protocol. The protocol is based on a single private, non-shared key cryptosystem; the security of this cryptosystem is based on a new hardness (secret base) assumption. We prove security for the secret base assumption in an extended generic group model. We also show parameters that ensure security against a lattice-based attack. We measure pe...

This paper introduces a cryptographic paradigm called selfescrowed encryption, a concept initiated by kleptography. In simple words, a self-escrowed public-key cryptosystem features the property that the scheme’s public and private keys are connected to each other by the mean of an other cryptosystem, called the master scheme. We apply this notion to the design of auto-recoverable autocertifiab...

Implementing public-key cryptography on passive RFID tags is very challenging due to the limited die size and power available. Typical public-key algorithms require complex logical components such as modular exponentiation in RSA. We demonstrate the feasibility of implementing public-key encryption on low-power, low cost passive RFID tags to large-scale private identification. We use Oded Regev...