“CRYPTANALYSIS OF THE HAGELIN CRYPTOGRAPH” Wayne G. Barker

Abstract

During the last two centuries, the Mexican diplomatic service produced a huge amount of cryptographic documents. The author has collected, surveyed, and classified nearly 100 since he began to research this subject. In this article, the author shall describe and briefly comment on four different cryptosystems from the first half of the nineteenth century.     

CP-III: One Time Cypher Pad Manual Encryption Device

WordPerfect V4.2, produced by WordPerfect Corporation, is a popular word processing program for the IBM PC series of microcomputers. The program includes an encryption option and, in their handbook, the manufacturers claim that “if you forget the password, there is absolutely no way to retrieve the document.” The encryption is shown to be a simple affine Vigenère cipher with a significant weakness.     

基于Vigenère密码的数字图像置乱方法

数字图像的置乱技术是图像信息隐藏和伪装的重要的手段之一。该文基于经典的Vigenère密码理论,提出一种数字图像灰度置乱方法,给出利用这种方法进行数字图像置乱的算法流程。仿真实验及结果表明,经这种方法置乱后的图像直方图与白噪声图像的直方图相似度约为0.9,从而验证了该方法的有效性。通过对安全性能的讨论,以及与改进Grey编码进行灰度置乱方法的结果进行比较,证明该方法具有较好的实用性。     

Remarks on breaking the Vigenère autokey cipher

Abstract

It has been mentioned by Shannon that a Vigenère autokey ciphertext can be transformed into a Vigenère ciphertext, provided the length of the priming key is known. We revisit this transformation and argue that combining it with the Friedman test, in fact, allows revealing of the length of the priming key. Thus, Shannon’s transformation together with the Friedman test allow transforming a Vigenère autokey ciphertext into a Vigenère ciphertext without any prior information. This allows an adversary to solve a Vigenère autokey ciphertext as if it was a Vigenère ciphertext. In addition, we show that the same method can be used to solve a modification of the Vigenère autokey cipher used in the Russian Civil War in 1917–1922.     

ERROR-CORRECTING CODES AND CRYPTOGRAPHY PART I

Charles L. Dodgson, better known as Lewis Carroll, invented several polyal-phabetic ciphers by 1868. The two that he published are put into historical perspective in this paper. His Alphabet Cipher produces a Vigenère enciphered text, while his Telegraph Cipher is equivalent to a Beaufort cipher. In constructing the Telegraph Cipher, Dodgson used two sliding alphabets, similar to the St. Cyr slide invented by Auguste Ker-ckhoff fifteen years later. A program is available to explore these ciphers and another, the Variant Beaufort.     

How I deciphered a Robert E. Lee letter—and a note on the power of context in short polyalphabetic ciphers

We decrypt a message from Robert E. Lee, which is possibly too short for efficient analysis by classical cryptanalytic techniques, by exploiting the mistake of not encrypting the full contents of the message.     

Finding the key length of a Vigenère cipher: How to improve the twist algorithm

Abstract

A Vigenère cipher applies a single short key repeatedly to encrypt a plaintext. If a cryptanalyst correctly finds out the key length, the ciphertext can be divided into multiple instances of shift cipher and be broken by frequency analysis. To determine the key length, the twist algorithm, an alternate method to the standard Kasiski and Friedman tests, was recently proposed. In this article, we propose the twist⁺ algorithm, an improved twist algorithm, which can estimate the key length more accurately than the original twist algorithm.     

On the cryptography of James Leander Cathcart (1767–1843)

The author provides a brief study concerning the kind of cryptosystems which the Irish-American Diplomat James Leander Cathcart could have used during his activities in the Barbary states and a posterior attempt to do business with the governments of Mexico and some South American countries.     

FACTORING VIA SUPERENCYRPTION

It is shown that a Simmons and Norris cycling attack against an RSA public key cryptosystem can be modified to search for factors of the modulus of the system. The cycling can be accomplished by superencyrption or by repeated applications of a function chosen by the cryptanalyst. Finally, the safest choice of system parameters is discussed.     

A Fast Marching Method for the Area Based Affine Distance

In a previous paper, it was proved that the area based affine distance of a convex region in the plane satisfies a non-homogeneous Monge-Ampère differential equation. Based on this equation, in this paper we propose a fast marching method for the computation of this distance. The proposed algorithm has a lower computational complexity than the direct method and we have proved its convergence. And since the algorithm allows one to obtain a connection from any point of the region to the boundary by a path of decreasing distance, it offers a dynamic point of view for the area based affine distance.

西斯庭教堂天顶画及《最后的审判》赏析

《创世纪》与《最后的审判》是作为雕塑家的米开朗基罗的两大绘画巨制,也是文艺复兴时期最具盛名的艺术作品,本文通过对两幅作品的欣赏分析,揭示了米开朗基罗英雄式的精神世界和悲天悯人的人文主义思想。     

Efficient implementation of a generalized polak-ribière algorithm for nonlinear optimization

We have recently developed a new conjugate gradient type method, the Generalized Polak-Ribière (GPR) method, for unconstrained minimization. It is based on search directions that are parallel to the Newton direction of the restriction of the objective function f on the two dimensional subspace span{?g p}, with p a suitable direction in span{? g,s^?}, where g and s ^? are the current gradient and previous search direction respectively. The new approach proved to be considerably more efficient than the original Polak-Ribière method.

In this paper, various implementations of the GPR method are compared with a currently available standard NAG software routine and also with the Nocedal, Buckley-LeNir and Shanno's limited memory algorithms. The results demonstrate the general effectiveness of the new algorithm. We also give a very brief discussion of extensions of the GPR method that generate search directions parallel to Newton directions in subspaces of dimension greater than two.     

RS-232与CAN接口卡的设计

与传统的RS-232总线相比,CAN总线是一个高速、长距离、多主、经济的网络系统,特别适用于实时系统。其易用性和低成本使得CAN在汽车工业和自动化领域得到广泛的应用。因此设计高性能的RS-232与CAN总线的接口卡以代替传统的PC机的RS-232总线通信具有重要意义。本主要介绍了CAN总线的工作原理和RS-232与CAN接口卡的软硬件设计过程及注意事项。