In this paper, we present a practical attack on the signature scheme SFLASH proposed by Patarin, Goubin and Courtois in 2001 following a design they had introduced in 1998. The attack only needs the public key and requires about one second to forge a signature for any message, after a one-time computation of several minutes. It can be applied to both SFLASH which was accepted by NESSIE, as well...

We present W-OTS, a Winternitz type one-time signature scheme (W-OTS). We prove that W-OTS is strongly unforgeable under chosen message attacks in the standard model. Our proof is exact and tight. The first property allows us to compute the security of the scheme for given parameters. The second property allows for shorter signatures than previous proposals without lowering the security. This i...

Chung, Huang, Lai and Chen proposed an ID-based signature scheme on the elliptic curve cryptosystem. Their scheme is secure but requires 60.12 1 for signature generation and 87.24 1 for signature verification. In this article, we propose an improvement of their signature scheme with three results: The improved scheme reduces about 50% and 33% of time complexity respectively for both signature g...

The primitive of private broadcast encryption introduced by Barth, Boneh and Waters, is used to encrypt a message to several recipients while hiding the identities of the recipients. In their construction, a recipient has to first decrypt the received ciphertext to extract the verification key for one-time signature. He then uses the verification key to check whether the ciphertext is malformed...

We contrast the two approaches to “classical” signature change used by Hayward with the one used by us (Hellaby and Dray). There is (as yet) no rigorous derivation of appropriate distributional field equations. Hayward’s distributional approach is based on a postulated modified form of the field equations. We make an alternative postulate. We point out an important difference between two possib...

A new signature file method, Multi-Frame Signature File (MFSF), is introduced by extending the bit-sliced signature file method. In MFSF, a signature file is divided into variable sized vertical frames with different on-bit densities to optimize the response time using a partial query evaluation methodology. In query evaluation the on-bits of the lower onbit density frames are used first. As th...

Introduction: A one-way function is needed in any digital signature scheme. Without using a secure one-way function, a digital signature can be easily forged [l, 21. There are some well-known oneway hash functions, such as the MD4, MD5, SHA, etc. There exists a major difference of security assumptions between digital signature schemes and one-way functions. The security assumptions of most sign...