Most ancient Chinese padlocks are key-operated locks with splitting springs, and partially keyless letter-combination locks. They can be characterized based on the types of locks, the shapes of locks, the engravings of locks, the materials of locks, and the mechanisms of locks. Some locks and keys are not only very beautiful and artistic colorful, but also with various designs. As a result, a s...

In this paper we propose the use of Boolean permutations to design public key cryptosystems. The security of the cryptosystems is based on the diiculty of inverting Boolean permutations. Using two Boolean permutations for which the inverses are easy to nd, one can construct a composite Boolean permutation which is hard to invert. The paper proposes three such Boolean permutation based public ke...

As a special type of factorization of finite groups, logarithmic signature (LS) is used as the main component of cryptographic keys for secret key cryptosystems such as PGM and public key cryptosystems like MST1, MST2 and MST3. An LS with the shortest length is called a minimal logarithmic signature (MLS) and is even desirable for cryptographic constructions. The MLS conjecture states that ever...

Few days ago Grigoriev and Shpilrain have proposed to build a system for transmission of information without a shared secret, or essentially a sort of public key cryptosystem, based on properties of physical systems [2]. In this paper we show that their second scheme based on capacitors is insecure and extremely easy to break in practice.

We investigate the discrete logarithm problem over jacobians of hyperelliptic curves suitable for public-key cryptosystems. We focus on the case when the definition field has small characteristic 2, 3, 5 and 7, then we present hyperelliptic cryptosystems that resist against all known attacks. We further implement our designed hyperelliptic cryptosystems over finite fields F2n in software on Alp...

We develop a public key cryptosystem based on invariants of diagonalizable groups. Theoretical results about degrees of invariants, which are related to the security of such cryptosystem, are derived. Further, we derive results on invariants of superanalogs of tori.

Consider the RSA public key cryptosystem with the parameters N = pq, q < p < 2q, public encryption exponent e and private decryption exponent d. In this paper, cryptanalysis of RSA is studied given that some amount of the Most Significant Bits (MSBs) of d is exposed. In Eurocrypt 2005, a lattice based attack on this problem was proposed by Ernst, Jochemsz, May and de Weger. In this paper, we pr...

Yamamota's notion of partial secrecy is extended to Public Key Cryptosystems: the security of a cryptosystem depends on keeping some function of the original record secret, while sending the relevant message (also a function of the original record). Notions of security and semantic security are introduced and compared for such cryptosystems, and securitypreserving reductions between such system...

MIXes are a means of untraceable communication based on a public key cryptosystem, as published by David Chaum in 1981 (CACM 24/2, 84-88) (=[6]). In the case where RSA is used as this cryptosystem directly, i.e. without composition with other functions (e.g. destroying the multiplicative structure), we show how the resulting MIXes can be broken by an active attack which is perfectly feasible in...

The Bivariate Function Hard Problem (BFHP) has been in existence implicitly in almost all number theoretic based cryptosystems. This work defines the BFHP in a more general setting and produces an efficient asymmetric cryptosystem. The cryptosystem has a complexity order of O(n) for both encryption and decryption.