加解密算法Blowfish在单片机上的应用

Blowfish算法是在1993年由Bruce Schneier等提出的一种对称分组加密算法[1],具有快速、安全、简单、紧凑等优点。本文分析了Blowfish算法的加密、解密过程和性能,在单片机上实现了该算法,并将它们封装成加密盒,有效地保护了大型软件的知识产权,取得了良好的实用效果。

用友软件问答

问我公司在做“总账工具”中的“凭证引入”的时候,在数据源中我引用了数据库(后缀是.MDB),但在点击了“凭证引入”时电脑提示说要用.TXT文件,我又在数据源里的数据库的后缀名由.MDB改成为.TXT时,电脑又提示说.TXT文件的格式不适合。

一种基于Huffman和LZW编码的移动应用混淆方法

二进制混淆技术在规避恶意软件分析、防止利用逆向工程篡改中扮演着重要的角色.一些广泛使用的混淆技术关注于基于语法的检测,基于语义的分析技术在很多年前也已经被提出以防止逃避检测.近年来,一些考虑到统计特征和基于语义的二进制混淆技术开始被提出,这些方法开始关注混淆的隐蔽性,但总体来说效率较低或无法同时考虑到安全性的要求.提出一种针对Android移动应用的、基于Huffman编码和LZW编码的二进制混淆技术,同时将强度、开销和隐蔽性等考虑在内,具备规避基于统计特性和语义特征检测的能力.该技术构造混淆所需的指令编码表,一方面利用编码表对原始指令序列进行置乱,提高混淆技术的隐蔽性;另一方面,将核心编码表从代码执行数据段分离,通过白盒AES加密的方式在提高混淆技术本身安全性的同时隐藏密钥及密钥查找算法.研发出该技术工具原型Obfus Droid.最后,从安全强度、开销、平台适应性和隐蔽性这几个方面,对该技术进行评估和阐述.

A Symmetric Key Exchange Protocol Bsaed on Virtual S-Box

Based on the theory of polymorphic virtual S-box, the paper presents a symmetric key exchange protocol to solve the problem of session keys delete shared in the computational complexity temporary trading scenario. Both parties jointly construct a highly nonlinear SPN core algorithm. The paper the connotation of polymorphic cipher theory, making use of the method of self-compiler based expansion factor to collect random parameter sets held by each of the parties containing its own information 5-tuple private keys array Kpa[5] and Kpb[5].The more efficient polymorphism virtual S-box is constructed. The method of secret split for the public key cryptography features can be implemented by symmetry cipher system. The research results will provide a theoretical basis to solve the key exchange problems for short- term communications partner based on symmetric cryptography.

Effective method for the design of S-Boxes satisfying the strict avalanche criterion(SAC)

The strict avalanche criterion(SAC)is one of the most important cryptographic criteria for substitution boxes(S-boxes)used in many symmetric encryption systems.However,there are few constructive methods for S-boxes fulfilling the SAC until now.In this paper,to construct S-boxes satisfying the SAC directly,we generalize the concatenation techniques of Boolean functions to S-boxes.Using the idea of concatenating small variable S-boxes,we present a simple yet effective construction method of S-boxes satisfying the SAC.Finally,a simple example on how to construct SAC S-boxes with large input variables by small variables SAC S-boxes is given.

ANALYSIS OF MINIMUM NUMBERS OF LINEARLY ACTIVE S-BOXES OF A CLASS OF GENERALIZED FEISTEL BLOCK CIPHERS

For a class of generalized Feistel block ciphers, an explicit formula for the minimum numbers of linearly active S-boxes of any round r is presented.

基于可信执行环境的数字版权风险分析及防护要求解读

数字版权保护技术是保障影视行业健康成长的重要手段,中国广播电视总局建设DRM平台用于监管数字版权的申请、分发、使用。DRM平台由两个部分组成,分别是DRM服务器端和DRM客户端设备。由于客户端设备运行于非可信环境下,因此需要客户端设备具备一定的安全防护能力。本文根据DRM客户端常见的安全风险和防护手段,对DRM客户端保护轮廓内提出的安全要求展开解读分析。