Merkle Tree Digital Signature and Trusted Computing Platform

Lack of efficiency in the initial key generation process is a serious shortcoming of Merkle tree signature scheme with a large number of possible signatures. Based on two kinds of Merkle trees, a new tree type signature scheme is constructed, and it is provably existentially unforgeable under adaptive chosen message attack. By decentralizing the initial key generation process of the original scheme within the signature process, a large Merkle tree with 6.87×10^10 possible signatures can be initialized in 590 milliseconds. Storing some small Merkle trees in hard disk and memory can speed up Merkle tree signature scheme. Mekle tree signature schemes are fit for trusted computing platform in most scenarios.

Conventional and Improved Digital Signature Scheme: A Comparative Study

Due to the rapid growth of online transactions on the Internet, authentication, non-repudiation and integrity are very essential security requirements for a secure transaction. To achieve these security goals, digital signature is the most efficient cryptographic primitive. Many authors have proposed this scheme and prove their security and evaluate the efficiency. In our paper, we present comprehensive study of conventional digital signature schemes based on RSA, DSA and ECDSA (Elliptic Curve Digital Signature Algorithm) and the improved version of these scheme.

A DIGITAL SIGNATURE-BASED VISUAL CRYPTOGRAPHY SCHEME FOR IMAGE DISCRIMINATION AND MANAGEMENT

Visual cryptography is a cryptographic technique which emerges in the information security domain in recent years. Each of the sharing sub-keys may be a stochastic noise image or a significative image with no information on the original key. But a mass of sub-keys have to be saved actually, which faces the problem of inconvenient discrimination and management. This paper presents a visual cryptography scheme based on the digital signature for image discrimination and management, applying the digital signature and the time-stamp technology to the visual cryptography scheme. The scheme both solves the problem on the storage and management of the sharing sub-keys, increases the verification of image contents, thus enhances the validity of storage and management without security effect.

DESIGN OF A DIGITAL SIGNATURE SCHEME BASED ON FACTORING AND DISCRETE LOGARITHMS

Objective Focusing on the s ecurity problem of authentication and confidentiality in the context of computer networks, a digital signature scheme was proposed based on the public key crypt osystem. Methods Firstly, the course of digital signature based on the public key cryptosystem was given. Then, RSA and ELGamal schemes were de scribed respectively. They were the basis of the proposed scheme. Generalized EL Gamal type signature schemes were listed. After comparing with each other, one s cheme, whose Signature equation was (m+r)x=j+s modΦ(p) , was adopted in the des igning. Results Based on two well-known cryptographic assumpti ons, the factorization and the discrete logarithms, a digital signature scheme w as presented. It must be required that s' was not equal to p'q' in the signing p rocedure, because attackers could forge the signatures with high probabilities i f the discrete logarithms modulo a large prime were solvable. The variable publi c key “e” is used instead of the invariable parameter “3” in Harn's signatu re scheme to enhance the security. One generalized ELGamal type scheme made the proposed scheme escape one multiplicative inverse operation in the signing proce dure and one modular exponentiation in the verification procedure. Concl usion The presented scheme obtains the security that Harn's scheme was originally claimed. It is secure if the factorization and the discrete logarithm s are simultaneously unsolvable.

An Identity-Based Scheme of Fair Exchange of Digital Signatures

Fair exchange of digital signatures is an important tool for signing digital contracts, e-payment and other electronic commerce actions. An ID-based scheme of fair exchange of digital signature is proposed in this paper. The protocol relies on a trusted third party, but is ＂optimistic＂, in that the third party is only needed in cases where one player attempts to cheat or simply crashes. The proposed scheme has properties of short signature, low computation and verification cost. It can realize exchange of digital signatures fairly and effic, iently. A key feature of our scheme is that it is identity-based, which needs no certificates and has a simple key management. To our best knowledge, this is the first identity based scheme of fair exchange of digital signatures.

Two Improved Digital Signature Schemes

In this paper, two improved digital signature schemes are presented based on the design of directed signature scheme. The peculiarity of the system is that only if the scheme is specific recipient, the signature is authenticated. Since the scheme adds the screen of some information parameters, the difficulty of deciphered keys and the security of digital signature system are increased.

Public-Key Cryptosystems with Secret Encryptor and Digital Signature

This paper describes and compares a variety of algorithms for secure transmission of information via open communication channels based on the discrete logarithm problem that do not require search for a generator (primitive element). Modifications that simplify the cryptosystem are proposed, and, as a result, accelerate its performance. It is shown that hiding information via exponentiation is more efficient than other seemingly simpler protocols. Some of these protocols also provide digital signature/sender identification. Numeric illustrations are provided.

Combining Public Key Encryption with Schnorr Digital Signature

This article presents a new signcryption scheme which is based on the Schnorr digital signature algorithm. The new scheme represents my personal contribution to signcryption area. I have implemented the algorithm in a program and here are provided the steps of the algorithm, the results and some examples. The paper also contains the presentation of the original Signcryption scheme, based on ElGamal digital signature and discusses the practical applications of Signcryption in real life. The purpose of the study is to combine the public key encryption with Schnorr digital signature in order to obtain less computational and communicational costs. Signcryption primitive is a better approach then Encrypt-then-Sign or Sign-then-Encrypt methods regarding the costs. All these algorithms offer the possibility to transmit a message over an insecure channel providing both authenticity and confidentiality.

A Secure Hardware Implementation for Elliptic Curve Digital Signature Algorithm

Since the end of the 1990s,cryptosystems implemented on smart cards have had to deal with two main categories of attacks:side-channel attacks and fault injection attacks.Countermeasures have been developed and validated against these two types of attacks,taking into account a well-defined attacker model.This work focuses on small vulnerabilities and countermeasures related to the Elliptic Curve Digital Signature Algorithm(ECDSA)algorithm.The work done in this paper focuses on protecting the ECDSA algorithm against fault-injection attacks.More precisely,we are interested in the countermeasures of scalar multiplication in the body of the elliptic curves to protect against attacks concerning only a few bits of secret may be sufficient to recover the private key.ECDSA can be implemented in different ways,in software or via dedicated hardware or a mix of both.Many different architectures are therefore possible to implement an ECDSA-based system.For this reason,this work focuses mainly on the hardware implementation of the digital signature ECDSA.In addition,the proposed ECDSA architecture with and without fault detection for the scalar multiplication have been implemented on Xilinxfield programmable gate arrays(FPGA)platform(Virtex-5).Our implementation results have been compared and discussed.Our area,frequency,area overhead and frequency degradation have been compared and it is shown that the proposed architecture of ECDSA with fault detection for the scalar multiplication allows a trade-off between the hardware overhead and the security of the ECDSA.

基于DSP的CIS信号采集与处理技术

CIS(接触式图像传感器 )是一种新型图像传感器。介绍了CIS的主要结构、特点和工作原理 ,提出了一种基于DSP的CIS信号采集与处理方案。与传统的图像采集系统相比 ,该系统由于采用CIS作为图像传感器 ,DSP作为控制和运算核心 ,因而具有电路简单 ,控制方便的特点。最后 ,给出了该系统在实际应用中的工作波形。

试论CIS战略在航空运输企业的实施

自从IBM公司首创CIS战略并取得极大成功以来,CIS的浪潮风起云涌。国内最早的CIS由太阳神引发,此后历经十几年的积淀,出现了海尔、联想等范例。当今,中国航空运输企业要进入国际市场,同样离不开深刻、完整的CIS和与之相关的品牌运作的理念。以“势”的运用为核心,分析CIS战略在航空运输企业的运作过程,目的在于通过CIS战略的实施,确立企业的品牌形象,提升企业的综合竞争能力,使其在国际市场的竞争中占有一席之地。

ECIS:一个安全的电子商务管理平台

虽然电子商务无法提供解决ｄｏｔ ｃｏｍ公司不能赢利的灵丹妙药，但是其能提供一套有效的工具帮助传统产业公司增加收入、降低成本、和提供更好的客户服务。本文提出ＥＣＩＳ（电子商务基础服务平台）的概念－该平台可以作为一个网络操作系统，帮助企业从电子商务系统中获得最大的效益。

Digital Multi-Signature Based on the Controlled Quantum Teleportation

In this paper, a scheme which can be used in multi-user quantum digital signature is proposed. The scheme of signature and verification is based on the characters of GHZ （Greenberger-Horne-Zeilinger） states and controlled quantum teleportation. Different from the digital signatures based on computational complexity, this scheme is unconditional secure, and compared to the former presented quantum signature scheme, it does not rely on an arbitrator to verify the signature and realize a message can be signed by multi-user together.

Effective generalized equations of secure hyperelliptic curve digital signature algorithms

A hyperelliptic curve digital signature algorithm （HECDSA） can be viewed as the hyperelliptic curve analogue of the standard digital signature algorithm （DSA）. This article discusses divisor evaluations, the basic HECDSA, variants, two HECDSA equations and a 4-tuple HECDSA scheme, and puts forward a generalized equation for HECDSA. From this generalized equation, seven general HECDSA types are derived based on the efficiency requirements. Meanwhile, the securities of these general HECDSA types are analyzed in detail.

Digital Signature Based on ISRSAC

Digital signature has recently played an increasingly important role in cyberspace security.Most of them are based on the public key cryptography.Public key cryptography is a mainstream cryptographic algorithm system that has been widely used in cyberspace security in recent years.The most classic public key cryptography algorithm is RSA and its difficulty is based on the large integer decomposition problem.In 2017,ISRSAC was proposed by M.Thangaval.ISRSAC has made security improvements to the RSA algorithm by increasing the complexity in factoring the value of modulus‘n’.A digital signature algorithm based on ISRSAC algorithm was completed in this paper,and furthermore,a proxy signature algorithm based on ISRSAC and two kinds of multi-signature algorithms were presented,which include sequential multi-signature and broadcasting multi-signature.

Digital signature systems based on smart card and fingerprint feature

Two signature systems based on smart cards and fingerprint features are proposed. In one signature system, the cryptographic key is stored in the smart card and is only accessible when the signer＇s extracted fingerprint features match his stored template. To resist being tampered on public channel, the user＇s message and the signed message are encrypted by the signer＇s public key and the user＇s public key, respectively. In the other signature system, the keys are generated by combining the signer＇s fingerprint features, check bits, and a rememberable key, and there are no matching process and keys stored on the smart card. Additionally, there is generally more than one public key in this system, that is, there exist some pseudo public keys except a real one.

Cryptanalysis on AW digital signature scheme based on error-correcting codes

In 1993, Alabhadi and Wicker gave a modification to Xinmei Digital Signature Scheme based on error-correcting codes, which is usually denoted by AW Scheme. In this paper we show that the AW Scheme is actually not secure: anyone holding public keys of the signatory can obtain the equivalent private keys, and then forge digital signatures for arbitrary messages successfully. We also point out that one can hardly construct a digital signature scheme with high-level security due to the difficulty of decomposing large matrixes.

Image Authentication Based on Digital Signatureand Semi-Fragile Watermarking

This paper proposes an authentication scheme for JPEG images based on digital signature and semi-fragile watermarking. It can detect and locate malicious manipulations made to the image, and verify the ownership of the image at the same time. The algorithm uses the invariance of the order relationship between two DCT coefficients before and after JPEG compression to embed image content dependent watermark, therefore the watermark can survive the JPEG lossy compression. Since the scheme is based on the security of the cryptographic hash function and public key algorithm, it is believed to be secure to the extent that cryptography is believed to be. Theoretical analysis and experimental results show that the proposed scheme has the desired property and good performance for image authentication.