Craig P. Bauer

Cracking Matrix Encryption Row by Row

Abstract The Hill Cipher, also known as matrix encryption, uses matrices to encipher and decipher text. Various attacks, such as those found by Jack Levine [2 3 5], have been published for this system. This article reviews a few previous results and presents a powerful new attack in which the rows of the matrix can be determined independent of one another, greatly reducing the amount of time needed for decipherment.

A STATISTICAL ATTACK ON THE RUNNING KEY CIPHER

The frequencies of n-graphs, groups of n letters, for n as large as 6 are compiled and used to launch a statistical attack on a running key cipher. Programs written in C++ make the calculations possible. The results of the attack for various values of n are analyzed.

The Cryptologic Contributions of Dr. Donald Menzel

Abstract Dr. Donald H. Menzel is well known for his work in astronomy, but his cryptologic work has never received a thorough review. The present article describes how his interest in this area was first sparked and provides the details of the secret class he led in “Naval Communications” (really cryptanalysis) at Radcliffe College during World War II. This class served as a prototype and was copied elsewhere. A sketch of some of the classified work he carried out during the war, and after, as a consultant, is also included, along with a brief overview of Menzels personality and other interests.

RESULTS OF AN AUTOMATED ATTACK ON THE RUNNING KEY CIPHER

ABSTRACT The running key cipher uses meaningful text as the key. Since the message also consists of meaningful text, the result is obtained by combining valid words. Automated attacks can find all such combinations that yield a given ciphertext. The results of these attacks are presented in this paper.

CRYPTOLOGY IN YORK PENNSYLVANIA

York College of Pennsylvania [46] and Penn State York [36], two colleges separated by only a few miles, both offer unique approaches to the subject of cryptology. The manner in which the courses are delivered is detailed along with the advantages of the geographical location.

The Early History of Voice Encryption

The evolution of voice encryption (a.k.a. ciphony) is detailed from the 1920s through the work of Alan Turing at the end of World War II. The systems covered are invertors, the A-3 Scrambler, SIGSALY, and Delilah. The human cost of poor voice encryption is illustrated by the failure of and consequent lack of trust in the A-3 Scrambler prior to and during World War II. The simple manner in which logarithms and modular arithmetic played a key role in SIGSALY is described, along with other key features. These may be put to use in the classroom to demonstrate practical and extremely important applications of basic mathematical ideas. Alan Turing’s work on SIGSALY is detailed along with his efforts to create an even better system, Delilah. Turing’s mission to Germany to ascertain the depth of the Nazi’s knowledge of ciphony is also discussed. Full historic context is provided to demonstrate the tremendous impact this technology had on the twentieth century.

Exploring Mathematics with the Computer

Abstract A detailed description is provided of a 200-level 3-credit course introducing ways in which mathematics may be explored with the use of a computer. This may serve as a template for such courses or be taken piecemeal for use in other classes. The original course was aimed at mathematics and mathematics education majors.

Review of Unveiling the Mystic Ciphers by Dave Ramsden

Years ago, I began writing a book on unsolved ciphers. Despite my efforts to keep it brief, it grew to well over 600 pages. I found a tremendous number of very interesting unsolved ciphers, and 600 pages was the smallest book I could produce without feeling miserable about the material I was leaving out. Actually, a lot of material was left out, and Klaus Schmeh seems to be discovering new examples at an increasing rate. Klaus is a German computer scientist and editorial board member of this journal. Readers are encouraged to visit his blog, where his latest finds appear regularly (Schmeh 2016). He has also written a book on unsolved ciphers (Schmeh 2012). In Unveiling the Mystic Ciphers by Dave Ramsden, you can read about one famous example of an unsolved cipher that I was only able to treat very briefly. As a bonus, Ramsden offers a possible solution. Solutions to famous unsolved ciphers appear frequently. The vast majority of these are produced by amateurs, and they are typically unable to convince any experts that their solutions are correct. Usually, the “solvers” are insistent that they are right, regardless of how many people they fail to convince. Ramsden is a refreshing exception. He even wrote, “This book does not, however, presume to be indisputable.” The rest of this review simply provides a description of the cipher with a bit of context and my reaction to Ramsden’s solution. I will not steal his thunder by reproducing his proposed solution here. The unsolved cipher that is the focus of Unveiling the Mystic Ciphers was created by Thomas Anson (1695–1773). He became one of the wealthiest men in England and poured a tremendous amount into renovating his family estate at Shugborough Hall in Staffordshire. Among the many monuments and works of art he had constructed or placed on the property was one known as the Shepherd’s Monument (Figure 1). This monument includes (beneath the frame around the figures) what is believed to be an enciphered dedication (Figure 2).

James Sanborn’s Kryptos and the matrix encryption conjecture

ABSTRACT James Sanborn’s sculpture, Kryptos, commissioned by the CIA, consists (in part) of four enciphered messages. These have attracted a tremendous amount of attention, and only the first three have been solved. In the present article, the authors provide a brief summary of each cipher and examine evidence that the fourth makes use of matrix encryption. They also provide results of brute force attacks for the 2 × 2 and 3 × 3 cases. Sanborn’s latest hint was of great value in testing these possibilities. Room for further testing is indicated for those wishing to continue the attack.

Friedman Auditorium Times Two

Abstract This article reports on the dedication of the Elizebeth Smith Friedman auditorium at the Washington DC headquarters of the ATF.