Optimal Asymmetric Encryption and Signature Paddings

Strong security notions often introduce strong constraints on the construction of cryptographic schemes: semantic security implies probabilistic encryption, while the resistance to existential forgeries requires redundancy in signature schemes. Some paddings have thus been designed in order to provide these minimal requirements to each of them, in order to achieve secure primitives. A few years ago, Coron et al. suggested the design of a common construction, a universal padding, which one could apply for both encryption and signature. As a consequence, such a padding has to introduce both randomness and redundancy, which does not lead to an optimal encryption nor an optimal signature. In this paper, we refine this notion of universal padding, in which a part can be either a random string in order to introduce randomness or a zeroconstant string in order to introduce some redundancy. This helps us to build, with a unique padding, optimal encryption and optimal signature: first, in the...

• Type: Conference
• Year: 2005
• Where: ACNS
• Authors: Benoît Chevallier-Mames, Duong Hieu Phan, David Pointcheval
• Keywords: ACNS 2005, Cryptography, Optimal Encryption, Optimal Signature, Universal Padding