Attribute based signature (ABS) is a novel cryptographic primitive, which enables a party to sign messages for any predicate satisfied by their attributes. However, heavy computational cost is required during the verification procedure in most existing ABS schemes, which may need many pairing operations. Pairings are costly operation when compared to exponentiation in the base group. As a resul...

Sequential aggregate signature schemes allow n signers, in order, to sign a message each, at a lower total cost than the cost of n individual signatures. We present a sequential aggregate signature scheme based on trapdoor permutations (such as RSA) that, unlike prior such proposals, does not require a signer to verify the received aggregate before adding a signature on a new message to it. In ...

Signature schemes from the RSA assumption are very important because of their highly reliable security. Despite their importance, only a few digital signature schemes from the RSA assumption are currently known. Thus, improvement of efficiency in this area seems to be very important. In this paper, we propose various signature schemes from the RSA assumption. First, we propose a scheme that sim...

The use of biometric technologies for human identity verification is growing rapidly in civilized society and showing its advancement towards the usability of biometrics for security. Off-line signature verification is considered as a behavioral characteristic based biometric trait in the field of security and the prevention of fraud. So, offline signatures are extensively used as a means of pe...

This paper presents a new approach for document image decomposition and verification based on connected component analysis and geometric properties of labeled regions. The database contains document images with Persian/Arabic text combined with English text, headlines, ruling lines, trademarks and cursive signatures. In particular, Persian/Arabic signature extraction is investigated using speci...

signatures: the functional approach and the parametric approach. This paper presents a new approach for dynamic handwritten signature verification (HSV) using the Neural Network with verification by the Conjugate Gradient Neural Network (NN). It is yet another avenue in the approach to HSV that is found to produce excellent results when compared with other methods of dynamic. Experimental resul...

BIOMETRIC FEATURES HAVE GREAT IMPORTANCE IN AUTHENTICATION SYSTEMS NOWADAYS. ONE OF THE MOST IMPORTANT AND CONVENTIONAL BIOMETRICS IS SIGNATURE. IN THIS PAPER, WE PROPOSED A SYSTEM WHICH HAS TWO INDEPENDENT PHASES FOR OFFLINE SIGNATURE IDENTIFICATION AND VERIFICATION. THE IDENTIFICATION PHASE IS BASED ON TSR (TRIANGLE SPATIAL RELATIONSHIP) THAT IS A ROTATION INVARIANT FEATURE EXTRACTION METHOD....

In this paper we analyze the application of a formal proof system to the discrete logarithm problem used in publickey cryptography. That means, we explore a computer verification of the ElGamal encryption scheme with the formal proof system Isabelle/HOL. More precisely, the functional correctness of this algorithm is formally verified with computer support. Besides, we present a formalization o...

We propose a secure threshold signature scheme without trusted dealer. Our construction is based on the recently proposed signature scheme of Waters in EUROCRYPT’05. The new threshold signature scheme is more efficient than the previous threshold signature schemes without random oracles. Meanwhile, the signature share generation and verification algorithms are non-interactive. Furthermore, it i...

In the paper, we analyze two signature schemes. The first is a (tj , t, n) threshold group signature scheme proposed by Shi and Feng in [1]. The second is a fair blind signature scheme proposed by Feng in [2]. Our results show that both schemes are forgeable. Besides, we introduce a concept, i.e., suspended factor, to describe the common error in designing signature scheme, which means that som...