Efficient Remote Data Possession Checking in Critical Information Infrastructures

Checking data possession in networked information systems such as those related to critical infrastructures (power facilities, airports, data vaults, defense systems, etc.) is a matter of crucial importance. Remote data possession checking protocols permit to check that a remote server can access an uncorrupted file in such a way that the verifier does not need to know beforehand the entire file that is being verified. Unfortunately, current protocols only allow a limited number of successive verifications or are impractical from the computational point of view. In this paper, we present a new remote data possession checking protocol such that: 1) it allows an unlimited number of file integrity verifications; 2) its maximum running time can be chosen at set-up time and traded off against storage at the verifier.     

FPGA Implementation(s) of a Scalable Encryption Algorithm

SEA is a scalable encryption algorithm targeted for small embedded applications. It was initially designed for software implementations in controllers, smart cards, or processors. In this letter, we investigate its performances in field-programmable gate array (FPGA) devices. For this purpose, a loop architecture of the block cipher is presented. Beyond its low cost performances, a significant advantage of the proposed architecture is its full flexibility for any parameter of the scalable encryption algorithm, taking advantage of generic VHDL coding. The letter also carefully describes the implementation details allowing us to keep small area requirements. Finally, a comparative performance discussion of SEA with the advanced encryption standard Rijndael and (a cipher purposed for efficient FPGA implementations) is proposed. It illustrates the interest of platform/context-oriented block cipher design and, as far as SEA is concerned, its low area requirements and reasonable efficiency.     

L’état de l’art en matière de techniques à clé publique

Restricted to an analysis of technical evolutions, this document does not deal with the use of public keys in communication and broadcasting networks. Smart card is the only application which is partially dealt with, not because it should be an exceptional application, but rather because smart cards are very efficient and very secure for both storing and using secret parameters. This document is a brief synthesis of this large subject where randomness and redundancy play the major roles, mainly in integrity techniques: identification, authentication and signature.     

Normalisation in diminished-radix modulus transformation

Modular multiplication goes faster if the modulus has a diminished-radix (DR) form. The authors precisely quantify the number of bits necessary to transform any modulus into its DR form     

SOI technology for future high-performance smart cards

Chips based on silicon-on-insulator (SOI) technology meet the tough performance and security requirements presented by smart cards. A test chip manufactured in a fully depleted SOI process incorporates a charge pump and random-number generator, critical smart-card circuit blocks.     

Efficient computation of full Lucas sequences

Recently, Yen and Laih (see IEE Poc. Comput. Digit. Tech., vol. 142, no. 2, p. 165-9, 1995) proposed an algorithm to compute LUC digital signatures quickly. This signature is based on a special type of Lucas sequence V_k. The authors generalise their method to any type of Lucas sequence, and extend it to the `sister' Lucas sequence, U_k . As an application, the order of an elliptic curve over GF(2^m) is computed quickly     

Chinese Remaindering Based Cryptosystems in the Presence of Faults

We present some observations on public-key cryptosystems that use the Chinese remaindering algorithm. Our results imply that careless implementations of such systems could be vulnerable. Only one faulty signature, in some explained context, is enough to recover the secret key. Received 19 April 1997 and revised 11 February 1998