一种新型的分组加密体制—面向字节的分组加密算法SAFER K—64

本文介绍了一种新型的分组加密算法，明文，密文都是长度为６４比特的块，密钥也为６４比特长。该算法面向字节加，能达到良好的扩散和混乱，运算快，抗攻击。     

一种新的图像自适应并行加密算法

提出了一种新的图像自适应并行加密算法。该算法根据奇偶加密轮次对图像进行水平或垂直分组,再对分组进行子块划分,并使用相邻块像素扰动混沌映射,同时设计了新的分组扩散方法,并使用S盒完成像素非线性替代。实验结果表明,新算法具有安全、简单、高效的特点,适合并行实现。     

一种新的基于混沌的图像加密算法

提出了一种基于混沌理论和循环移位的图像加密算法.先产生一个混沌序列,然后利用该序列与原图像进行异或运算和循环移位,得到初步加密图像,最后对图像进行Arnold变换得到加密图像.测试结果表明,该算法具有加密效果好、速度快、密钥空间大等优点.     

一种新的图像加密算法研究与应用

提出了一种新的混沌彩色图像加密算法.首先由Logistic和Cubic-Henon复合混沌映射生成混沌序列,再结合像素值替代和图像位置置乱方法对彩色图像进行加密,并利用"一幅图像一次密钥"的密钥同步方案,实现了一个基于混沌的图像保密通信系统.该算法具有一定的有效性和良好的加密性能.     

一种新的分组网QoS保障机制

文章针对分组网中实现QoS支持的必要性,提出了一种MPLS结合DiffServ的解决方案,并对方案的实现进行了比较详细的分析。     

一种基于交替密钥的分组结构彩色图像加密算法

基于循环迭代的加/解密机制,提出了一种新的彩色图像加密算法。该算法在彩色空间应用了仿射变换,将交替密钥生成算法与分组结构引入到彩色图像加密过程,采用二种混沌映射对彩色图像加密,在每一次交替加密过程中,通过对初始密钥循环移位生成相应的交替密钥并产生二种子密钥,用于二种混沌映射,从而增加了密钥空间,有效提高了彩色图像加密算法的安全性。实验结果表明,该彩色图像加密算法安全性好,免疫性强,效率高。     

一种新的抗分组丢失的语音分组传输法

针对IP和ATM此类基于分组原理传输信息的网络，进行实时语音通信时，存在因语音信息分组的可能丢失造成的服务质量（QoS）下降的问题，提出一种新的方法－－主次型多任务语音数据分组（MSMTSP）传输法，以减少对语音通信质量的影响。实验表明，增强系统码字的信息分组即使丢失了15％，对解码语音质量影响也不大；核心系统码字的信息分组丢失率不到5％时，影响很小，10％时能明显察觉，15％时语音质量明显下降，但不影响可懂度。     

一种新的IP分组丢弃策略PRDP

该文分析了IP业务在MPLS/DiffServ上运行的特点,从考虑业务量工程性能的角度出发提出了一种新的IP分组优先级的划分方法,并在此基础上给出了一种新的IP分组丢弃算法基于优先级的丢弃策略(PBDP)。考虑到随机早检测策略(RED)的优点,将PBDP与RED相结合,得到一种改进的算法基于优先级的RED策略(PRDP),仿真结果表明这种算法在提高全网性能上有优势,其性能优于传统的尾丢弃策略。     

一种新的HSDPA分组调度算法研究

目前已提出的HSDPA调度算法仅是基于用户的优先级进行数据分组的调度.文章考虑了3G系统的业务多样性,综合考虑用户的优先级和业务的级别,创新性地提出将两类分组调度算法,即基于业务类别的分组调度算法--加权公平排队算法,与基于用户优先级的调度算法--最短队列算法或者最长队列算法相结合后的调度算法.仿真的结果显示,提出的调度算法能满足不同业务要求的QoS.从吞吐量和延时来看,最短队列算法与加权公平排队算法结合方案优于最长队列算法与加权公平排队算法结合的方案.     

一种新的多分组联合译码方法

多分组译码目前有两种方式:分集合并和码字合并。但是这两种方法都是利用信道的 输出值,即译码之前的信道符号来合并。考虑到FEC的纠错功能,提出了输出联合码字合并的方法。 该方法将FEC译码器的输出值看作是传输分组经过较好信道后的一个输出分组,将其与重传分组进行 合并译码。理论推导和仿真结果证明新方法可以极大地降低系统的传输延时,同时没有增加系统的复 杂度。     

AES密码算法的VLSI实现

给出AES轮加密结构,详细分析MixColumns模块功能,提出基于VLSI实现的方案。用移位寄存器和异或单元代替有限域乘法模块,简化了电路的规模。在子密钥产生模块中,提出了根据密钥长度设计不同模块的方法,加快了芯片运行速度。     

OFDM双向多跳网络的新型比特和功率分配算法

结合新型双向多跳网络协议和正交频分复用技术,研究旨在保证通信质量情况下的自适应比特和功率分配算法,其目的是以较小发送功率和较高频谱效率完成通信。通过凸优化理论推导出最优功率分配算法,并提出一种基于贪婪原则的自适应比特分配算法,能够以较低的复杂度在实际工程中完成部署。仿真分析表明,提出的双向多跳算法是传统多跳协议频谱效率的2倍,所需发送功率是平均资源分配算法的1/3。     

分组密码算法KASUMI及其在WCDMA中的应用

本文对分组密码算法KASUMI的流程作了简要介绍,对其优缺点进行了分析。同时,对于它在第三代移动通信系统WCDMA中的应用做出了归纳,并阐述了该算法为核心的数据加密过程和信令完整性保护过程。     

全变异二进制位量子加密算法对电子政务实施的安全方案

引言“全变异二进制位量子算法”体系中,各位量子值的二进制表达式中1或0的数量和分布符合随机数标准;且位量子位序密钥的各位量子可按值的平均值大小循环分布成随机性系统密钥,因密文值为随机性的各量子值的相加值,即当明文设定为随机性,位量子密钥设定为随机性,则密文值为随机性,可用于各种随机性密钥的生成。而对任何明文的加密,只要明文间有1位的变化,其密文间必为整个值域的全变异,可抗已知明文攻击、线性攻击、明文间的冗余攻击。因密文可作为各种随机性密钥,因而对身份、口令等具备快速认证和鉴定,具备快速的密文的完整性和入侵检测…     

Shorter bit sequence is enough to break stream cipher LILI-128

LILI-128 is the stream cipher proposed as a candidate cipher for the New European Schemes for Signatures, Integrity, and Encryption (NESSIE) Project. Some methods of breaking it more efficiently than an exhaustive search for its secret key have been found already. The authors propose a new method, which uses shorter bit sequence to break LILI-128 successfully. An attack that can be made with less data can be a more practical threat. With only 2/sup 7/ bits of keystream, this method can break LILI-128 successfully. The efficiency of our attack depends on the memory size. For example, with 2/sup 99.1/ computations, our attack breaks LILI-128, if 2/sup 28.6/-bit memory is available.     

An ASIC implementation of low power and high throughput blowfish crypto algorithm

Information security has always been important in all aspects of life. It can be all the more important as technology continues to control various operations in our day to day life. Cryptography provides a layer of security in cases, where the medium of transmission is susceptible to interception, by translating a message into a form that cannot be read by an unauthorized third party. Several software implementations of blowfish crypto algorithms are described in the literature, but few attempts have been made to describe hardware implementations. The ultimate objective of the research presented in this paper is to develop low-power, high-throughput, real-time, reliable and secure crypto algorithm, which can be achieved through hardware implementations. The blowfish crypto algorithm is prototyped in 130 nm custom integrated circuit.     

A 128K word/spl times/8 bit dynamic RAM

A 1-Mb DRAM with 128K/spl times/8 bit organization is described. In designing the circuit, half V/SUB cc/ bit line precharge with dummy reverse circuits was adopted for noise reduction. The noise is estimated using a three-dimensional capacitance calculation. In realizing the chip, a 1-/spl mu/m NMOS process with double-level aluminum wiring was used.     

高性能网络加密平台

目前国内密码技术应用较少或常被不恰当地使用,原因是缺乏作为基础设施的平台支撑。本文介绍了一种集安全策略、传统密钥管理和公钥管理为一体的加密平台体系结构。     

An improvement to the bit stuffing algorithm

The bit stuffing algorithm is a technique for coding constrained sequences by the insertion of bits into an arbitrary data sequence. This approach was previously introduced and applied to (d,k) constrained codes. Results show that the maximum average rate of the bit stuffing code achieves capacity when k=d+1 or k=/spl infin/, while it is suboptimal for all other (d,k) pairs. Furthermore, this technique was generalized to produce codes with an average rate that achieves capacity for all (d,k) pairs. However, this extension results in a more complicated scheme. This correspondence proposes a modification to the bit stuffing algorithm that maintains its simplicity. We show analytically that the proposed algorithm achieves improved average rates over bit stuffing for most (d,k) constraints. We further determine all constraints for which this scheme produces codes with an average rate equal to the Shannon capacity.     

New bit rate reduction techniques for block truncation coding

Two simple and fast block truncation coding algorithms which require reduced bit rates are presented in this paper. The proposed algorithms are compared with the modified block truncation coding technique (MBTC) with regard to the mean square error (MSE), bit rates and subjective quality of the reconstructed images. It is found that the results obtained with the proposed algorithms at reduced bit rates are comparable to those obtained with the MBTC. Further, it is shown that one of the proposed algorithms yields results which are comparable to those achieved with more complex hybrid algorithms