Joint Quantization and Diffusion for Compressed Sensing Measurements of Natural Images

Recent research advances have revealed the computational secrecy of the compressed sensing (CS) paradigm. Perfect secrecy can also be achieved by normalizing the CS measurement vector. However, these findings are established on real measurements while digital devices can only store measurements at a finite precision. Based on the distribution of measurements of natural images sensed by structurally random ensemble, a joint quantization and diffusion approach is proposed for these real-valued measurements. In this way, a nonlinear cryptographic diffusion is intrinsically imposed on the CS process and the overall security level is thus enhanced. Security analyses show that the proposed scheme is able to resist known-plaintext attack while the original CS scheme without quantization cannot. Experimental results demonstrate that the reconstruction quality of our scheme is comparable to that of the original one.Comment: 4 pages, 4 figure

Chosen-plaintext attack of an image encryption scheme based on modified permutation-diffusion structure

Since the first appearance in Fridrich's design, the usage of permutation-diffusion structure for designing digital image cryptosystem has been receiving increasing research attention in the field of chaos-based cryptography. Recently, a novel chaotic Image Cipher using one round Modified Permutation-Diffusion pattern (ICMPD) was proposed. Unlike traditional permutation-diffusion structure, the permutation is operated on bit level instead of pixel level and the diffusion is operated on masked pixels, which are obtained by carrying out the classical affine cipher, instead of plain pixels in ICMPD. Following a \textit{divide-and-conquer strategy}, this paper reports that ICMPD can be compromised by a chosen-plaintext attack efficiently and the involved data complexity is linear to the size of the plain-image. Moreover, the relationship between the cryptographic kernel at the diffusion stage of ICMPD and modulo addition then XORing is explored thoroughly

Breaking a novel colour image encryption algorithm based on chaos

Recently, a colour image encryption algorithm based on chaos was proposed by cascading two position permutation operations and one substitution operation, which are all determined by some pseudo-random number sequences generated by iterating the Logistic map. This paper evaluates the security level of the encryption algorithm and finds that the position permutation-only part and the substitution part can be separately broken with only $\lceil (\log_2(3MN))/8 \rceil$ and 2 chosen plain-images, respectively, where $MN$ is the size of the plain-image. Concise theoretical analyses are provided to support the chosen-plaintext attack, which are verified by experimental results also.Comment: 5 pages, 1 figur

Interview of John Lukacs, Ph.D.

John Lukacs was born in 1924 in Budapest Hungary. He grew up in a middle class family raised by a Roman Catholic Father, and a Jewish mother. While he received most of his education in Hungary, he went to high school in Great Britain during his teenage years. During the Second World War, he was drafted into a forced labor battalion for much of the war. When German troops occupied Hungary in late 1944, he had to avoid getting sent to death camps by avoiding German patrols. In addition, he had to avoid being caught in the crossfire during the Siege of Budapest in December 1944 when the Soviets slowly pushed the Germans out of the city. After a living under Soviet occupied Budapest for less than a year, he left for the United States in 1946. In the United States, he worked at Chestnut Hill and LaSalle teaching history. Although he taught at both institutions until the 1980s, he preferred writing books and other academic articles not limited to: Winston Churchill, Hitler, the Soviet Union, the Eastern Bloc, and Pennsylvania history. Even after retirement, he wrote prolifically, publishing many works. He has been married three times and has two children. As of the time of the interview, he had no plans of writing in the foreseeable future. He currently resides in Phoenixville, PA. This interview focuses on his years and work as an educator full-time at Chestnut Hill College and part-time at La Salle College

The Molecular Gas Density in Galaxy Centers and How It Connects to Bulges

In this paper we present gas density, star formation rate, stellar masses, and bulge disk decompositions for a sample of 60 galaxies. Our sample is the combined sample of BIMA SONG, CARMA STING, and PdBI NUGA surveys. We study the effect of using CO-to-H_2 conversion factors that depend on the CO surface brightness, and also that of correcting star formation rates for diffuse emission from old stellar populations. We estimate that star formation rates in bulges are typically lower by 20% when correcting for diffuse emission. We find that over half of the galaxies in our sample have molecular gas surface density >100 M_sun pc^-2. We find a trend between gas density of bulges and bulge Sersic index; bulges with lower Sersic index have higher gas density. Those bulges with low Sersic index (pseudobulges) have gas fractions that are similar to that of disks. We also find that there is a strong correlation between bulges with the highest gas surface density and the galaxy being barred. However, we also find that classical bulges with low gas surface density can be barred as well. Our results suggest that understanding the connection between the central surface density of gas in disk galaxies and the presence of bars should also take into account the total gas content of the galaxy and/or bulge Sersic index. Indeed, we find that high bulge Sersic index is the best predictor of low gas density inside the bulge (not barredness of the disk). Finally, we show that when using the corrected star formation rates and gas densities, the correlation between star formation rate surface density and gas surface density of bulges is similar to that of disks.Comment: Accepted for publication in Ap

Interview of Frederick Van Fleteren, Ph.D.

Frederick Van Fleteren was born in St. Clair Shores, Michigan in 1941. He was raised by two devout Catholic parents who valued his education. He went to Catholic grade schools and colleges in the United States, as well as two Irish universities when he was getting his PhD. in philosophy. His interest in philosophy would guide his academic and professional career from his undergraduate years to the present day where he is a Philosophy professor at La Salle University. From 1967 until 1978, he was an ordained priest with the Augustinians. He received his B.A. and M.A. from Villanova in 1964 and 1968 respectively, and his PhD in ancient philosophy with a specialty in St. Augustine from the National University of Ireland and University College, Dublin in 1971. After leaving the priesthood in 1978, he worked as an assistant administrator at Crozer-Chester Medical Center at Crozer Pennsylvania in 1978, an executive director of the hospice program at Lourdes Hospital in Bingham New York from 1979 until 1981, and director of a hospice at Quakertown Pennsylvania from 1989 until 1995. He has been a professor at La Salle University since 1987, and has edited and published numerous academic articles and books since the 1970s