Certain cryptographic keys, such as a number which makes it possible to compute the secret decoding exponent in an RSA public key cryptosystem,1,5 or the system master key and certain other keys in a DES cryptosystem,3 are so important that they present a dilemma. If too many copies are distributed one might go astray. If too few copies are made they might all be destroyed. A typical cryptosyst...

A threshold signature or decryption scheme is a distributed implementation of a cryptosystem, in which the secret key is secret-shared among a group of servers. These servers can then sign or decrypt messages by following a distributed protocol. The goal of a threshold scheme is to protect the secret key in a highly fault-tolerant way. Namely, the key remains secret, and correct signatures or d...

In this paper, we fully break the Algebraic Surface Cryptosystem (ASC for short) proposed at PKC’2009 [3]. This system is based on an unusual problem in multivariate cryptography: the Section Finding Problem. Given an algebraic surface X(x,y, t) ∈ Fp[x,y, t] such that degxy X(x,y, t) = w, the question is to find a pair of polynomials of degree d, ux(t) and uy(t), such that X(ux(t),uy(t), t) = 0...

In many pairing-based cryptosystems, the secret keys are elements of bilinear groups. For safeguarding such secret keys or decrypting or signing in a threshold manner, Verifiable Secret Sharing (VSS) in bilinear groups is required. In this paper, we show a method of verifiably sharing a random secret in a bilinear group. Our method is simple and practical. It can be regarded as a generalisation...

Inthispaper,wepropose twosecureverifiablemulti-secret sharingschemes thatarebasedonnon-homogeneous linearrecursionsandelliptic curvesoverZN .Suchschemeshavesimpleconstructionandverificationphases.Moreover thesehavevarious techniques for the reconstruction phase. The security of the proposed schemes is based on the security of the ECRSA cryptosystem and the intractability of the ECDLP. 2007 Else...

The generalized secret sharing scheme is a method used to divide secret into a set of participants such that only the qualified subsets of participants can reconstruct the secret. In this paper, we first propose a new generalized secret sharing scheme with cheater detection. The security of the scheme is based on discrete logarithm problem. Based on this scheme, we present a group-oriented gene...

The popularity of biometrics and its widespread use introduces privacy risks. To mitigate these risks, solutions such as the helper-data system, fuzzy vault, fuzzy extractors, and cancelable biometrics were introduced, also known as the field of template protection. Fuzzy vault is a practical and promising scheme, which can protect biometric templates and perform secure key management simultane...

This paper identifies vulnerabilities to recently proposed countermeasures leakage power analysis attacks in FDSOI systems based on the application of a random body bias. The are analyzed and relative difficulty obtain secret key, once taken into account, compared original proposals. A new countermeasure, bias scheme, is then proposed. countermeasure equalization asymmetries static consumption ...

Multiplicative threshold schemes are useful tools in threshold cryptography. For example, such schemes can be used with a wide variety of practical homomorphic cryptosystems (such as the RSA, the El Gamal and elliptic curve systems) for threshold decryption, signatures, or proofs. The paper describes a new recursive construction for multiplicative threshold schemes which makes it possible to ex...