Solving the Key Escrow Problem of Identity-based Cryptosystems

Description

Identity-based cryptosystems are very useful in practice because they do not need expensive certificates for verifying users' public keys. They are considered to be a potential alternative to the currently used public key infrastructure which is known to be very costly to implement and maintain. In order to deploy identity-based cryptosystems to actual applications in the real world, the key escrow problem which is inherent to identity-based cryptosystems has to be solved. This problem concerns the privacy of users’ secret keys which are currently generated by and therefore known to a third party called the Key Generation Center (KGC) which is assumed to be trusted by all users. In practice, it is costly if it is not infeasible to establish the required extent of trust to the KGC. In this project, researchers plan to investigate methods to solve this problem with efficient implementation and provable security. Certificateless cryptography will be studied in detail. On security analysis, the researchers plan to improve the existing models and target to propose schemes which are proven secure under the improved models without any random oracle. On the implementation, the researchers target to devise new techniques which can help reduce computational complexity and minimize memory usage.