Decorrelation: A Theory for Block Cipher Security

Pseudorandomness is a classical model for the security of block ciphers. In this paper we propose convenient tools in order to study it in connection with the Shannon Theory, the Carter–Wegman universal hash functions paradigm, and the Luby–Rackoff approach. This enables the construction of new ciphers with security proofs under specific models. We show how to ensure security against basic differential and linear cryptanalysis and even more general attacks. We propose practical construction schemes.     

A weak cipher that generates the symmetric group

There has been recent interest in the permutation group generated by the round functions of a block cipher. In this paper we present a cautionary example of a block cipher which generates the full symmetric group yet is very weak.     

On the Construction of Pseudorandom Permutations: Luby—Rackoff Revisited

Luby and Rackoff [26] showed a method for constructing a pseudorandom permutation from a pseudorandom function. The method is based on composing four (or three for weakened security) so-called Feistel permutations, each of which requires the evaluation of a pseudorandom function. We reduce somewhat the complexity of the construction and simplify its proof of security by showing that two Feistel permutations are sufficient together with initial and final pairwise independent permutations. The revised construction and proof provide a framework in which similar constructions may be brought up and their security can be easily proved. We demonstrate this by presenting some additional adjustments of the construction that achieve the following: • Reduce the success probability of the adversary. • Provide a construction of pseudorandom permutations with large input-length using pseudorandom functions with small input-length. Received 2 August 1996 and revised 26 July 1997     

The research and design of reconfigurable computing for Block cipher

This paper describes a new specialized Reconfigurable Cryptographic for Block ciphers Architecture（RCBA）.Application-specific computation pipelines can be configured according to the characteristics of the block cipher processing in RCBA,which delivers high performance for cryptographic applications.RCBA adopts a coarse-grained reconfigurable architecture that mixes the appropriate amount of static configurations with dynamic configurations.RCBA has been implemented based on Altera’s FPGA,and representative algorithms of block cipher such as DES,Rijndael and RC6 have been mapped on RCBA architecture successfully.System performance has been analyzed,and from the analysis it is demonstrated that the RCBA architecture can achieve more flexibility and efficiency when compared with other implementations.     

Cryptanalysis of an image encryption scheme with a pseudorandom permutation and its improved version

Under Kerckhoff principle, this paper discusses the security property of an image encryption scheme with a pseudorandom permutation. Some findings on the security problems of the algorithm are reported in the following: (1) If each row or column of the plain-image matrix is the same, the receiver cannot decrypt correctly. (2) Each plain-text word is correlated with single cipher-text word, but independent of other cipher-text word, which cannot meet the principles of algorithm design-diffusion and confusion. (3) If the cycle numbers β are relatively small, statistics attack can be used to reveal some visual information of any other plain-images encrypted with the same secret key. Considering the above problems, we propose an improved algorithm and then analyze its performance. Theoretical analysis and simulation results show that the improved algorithm can obtain better cryptographic properties, such as statistical characteristics, difference characteristics, and so on.     

Lai-Massey结构伪随机特性研究

该文深入研究了Lai-Massey结构的伪随机特性。首先,证明了基于仿射几乎正形置换设计的3轮Lai- Massey模型并不具有伪随机特性,给出了Lai-Massey结构设计者所得结论的一个反例。其次,证明了双射为任意正形置换时,至少3轮Lai-Massey结构才具有伪随机特性;证明了双射为仿射正形置换时,至少4轮的Lai-Massey结构才具有超伪随机特性。结论表明,为构造伪随机特性更好的Lai-Massey结构实例,双射最好设计为非线性的正形置换或几乎正形置换。     

基于单片机的密码锁储物罐设计

设计了一款基于单片机的密码锁储物罐.该系统由STC89C52单片机控制,采用4×4矩阵键盘输入,LCD1602液晶输出.继电器驱动电磁锁以实现储物罐开锁闭锁功能,同时增加了蜂鸣器实现提示和报警功能.     

A cipher based on data-dependent permutations

Data-dependent permutations (DDP) are introduced as basic cryptographic primitives to construct fast hardware-oriented ciphers. Some variants of the DDP operations and their application in the cipher CIKS-1 are considered. A feature of CIKS-1 is the use of both the data-dependent transformation of round subkeys and the key-dependent DDP operations. Received March 2000 and revised May 2001 Online publication 29 August 2001     

伪随机二相码连续波信号参数估计算法

提出了一种伪随机二相码连续波信号参数估计算法。利用倍频法估计出载频和初相,由估计的载频和初相构造相关接收机,根据相关接收机的输出估计码元宽度、码元个数和码序列。     

一种安全可靠性高的全新IP核保护方法

提出了一种基于3DES加(解)密双方认证系统的IP核保护方法,主要用于保护基于SRAMD工艺FPGA设计的IP核电路。在配置好的FPGA中,通过IP核外附加的内部保护电路和外部验证设备之间的互相通信认证,确认使用者的合法性,可有效防止IP核信息配置到FPGA过程中的非法盗取。详细介绍了这种新IP核保护方法的原理、结构和实现过程,并设计了一套基于此技术的简化双方认证系统。     

Flexible construction of irregular partitioned permutation LDPC codes with low, error floors

Irregular partitioned permutation (IPP) low-density parity-check (LDPC) codes have been recently introduced to facilitate hardware implementation of belief propagation (BP) decoders. In this letter, we present a new method to construct IPP LDPC codes with great flexibility in the selection of code parameters. Meanwhile, small stopping sets are avoided in the code construction, thus good error floor performance can be achieved.     

Sparse sequence construction of LDPC codes

This letter proposes a novel and simple construction of regular Low-Density Parity-Check （LDPC） codes using sparse binary sequences. It utilizes the cyclic cross correlation function of sparse sequences to generate codes with girth 8. The new codes perform well using the sumproduct decoding. Low encoding complexity can also be achieved due to the inherent quasi-cyclic structure of the codes.     

抗功耗攻击的随机插入式分组密码系统

近年来涌现出许多抗功耗分析的方法,例如双轨电路法、掩码法和随机操作插入法。仔细分析这些方法可以发现它们都有潜在的缺陷,这些缺陷使得这些方法大都受制于大量的数据统计(包括高阶数据统计)。提出了一种在分组密码加解密过程中加入伪轮函数的方法。伪轮函数的加入使得加解密过程具有不可重复性,从而给功耗分析带来很大的麻烦。用51单片机仿真了这个设计,并进行了相关的功耗分析,结果显示该设计能很好地抵制功耗分析。     

一类新型置换的研究

本文对一类特殊置换——类全向置换进行了研究,并给出了此类置换的一些性质和构造方法。     

DES加密算法的VLSI实现方法

简述了DES加密算法的发展历史和核心思想,并给出了一种VLSI实现方法.并且在数据通道中采用了流水线结构,这样的结构比软件实现有着更好的加密性能.文中着重介绍了DES算法中的S-Box,替换和迭代过程.     

The M209 cipher machine: a war of words

The author describes the construction and operation of the M209 cipher machine as used by the US Army in the Second World War. It was one of several versions of the Hagelin machine, named after its inventor, Boris Hagelin, which was produced in Sweden. The author discusses the internal configuration, encipherment, overlapping, security, and cracking the code. The M209 remained in use until the mid-1970s when digital computers replaced them     

Simple construction of multiple interleavers: cyclically shifting a single interleaver

Utilizing multiple interleavers recently attracted increasing attention in many research areas. Interleaver generation should be simple in order to avoid huge memory requirements for storing interleaving patterns. We propose to derive multiple interleavers by cyclically shifting and self-interleaving a common mother interleaver in a few steps. Our focus is on the good user separation in interleave division multiple access systems. The proposed method may also find other application areas such as multi-dimensional concatenated codes.     

一类混沌序列密码的特性分析

本文对改进型数字滤波器混沌结构生成的序列密码进行了研究、通过对序列周期、平衡性及线性复杂度的性能分析表明,该结构生成的流密码序列在周期长度、随机统计特性和不可预测性方面体现了较好的性能,满足序列密码系统对密钥序列的要求,且易于实现。     

单圈T-函数的构造

构造了两类一元单圈T-函数,这两类T-函数在软件实现上速度快、效率高,而且所生成的序列线性复杂度高、稳定性强。此外,还研究了参数与单圈T-函数的关系,给出了一个由已有的一元单圈T-函数和一个偶参数来构造新的一元单圈T-函数的方法。     

基于AHB总线的多模式低功耗DES/3DES IP核的实现

设计了一种低功耗低资源的DES／3DES加解密软核,可以兼容ECB,CBC,CFB三种模式,具有AMBA AHB总线接口,可以方便集成在一些低功耗SoC下作为加解密数据协处理模块。该软核在90nm工艺130MHz时钟频率下逻辑综合结果为8835门,通过了FPGA验证,最高吞吐量达到416Mbps,表明其为可重用的软核。