A graphical simulator for the cryptanalysis of block ciphers

We have designed and implemented a graphical simulator for the use of students in the Master of Applied Science (information security) program at RMIT University in Melbourne, Australia. During this process, a lot of practical experience was gained which aids future designers who address similar problems, especially if the design aims include the realistic simulation, in a reasonable time, of a process, cryptanalysis - which often takes many days or weeks of computation by powerful computers

User-Generated Free-Form Gestures for Authentication : Security and Memorability

Jufo_ID: 50112 ; lyhenne: MobiSys.Peer reviewe

Excellent outcomes of laparoscopic esophagomyotomy for achalasia in patients older than 60 years of age

The effectiveness of an esophagomyotomy for dysphagia in elderly patients with achalasia has been questioned. This study was designed to provide an answer. A total of 162 consecutive patients with achalasia who had a laparoscopic myotomy and Dor fundoplication and who were available for follow-up interview were divided by age: <60 years (range, 14–59; 118 patients), and ≥60 years (range, 60–93; 44 patients). Primary outcome measures were severity of dysphagia, regurgitation, heartburn, and chest pain before and after the operation as assessed on a four-point Likert scale, and the need for postoperative dilatation or revisional surgery. Follow-up averaged 64 months. Older patients had less dysphagia (mean score 3.6 vs. 3.9; P < 0.01) and less chest pain (1.0 vs. 1.8; P < 0.01). Regurgitation (3.0 vs. 3.2; P = not significant (NS)) and heartburn (1.6 vs. 2.0, P = NS) were similar. Older patients were no different in degree of esophageal dilation, manometric findings, number of previous pneumatic dilatations, or previous botulinum toxin therapy. None of the older patients had previously had an esophagomyotomy, whereas 14% of younger patients had (P < 0.01). After laparoscopic myotomy, older patients had better relief of dysphagia (mean score 1.0 vs 1.6; P < 0.01), less heartburn (0.8 vs. 1.1; P = 0.03), and less chest pain (0.2 vs. 0.8, P < 0.01). Complication rates were similar. Older patients did not require more postoperative dilatations (22 patients vs. 10 patients; P = 0.7) or revisional surgery for recurrent or persistent symptoms (3 vs. 1 patients; P = 0.6). Satisfaction scores did not differ, and more than 90% of patients in both groups said in retrospect they would have undergone the procedure if they had known beforehand how it would turn out. This retrospective review with long follow-up supports laparoscopic esophagomyotomy as first-line therapy in older patients with achalasia. They appeared to benefit even more than younger patients

Long-term safety and outcome of a temporary self-expanding metallic stent for achalasia: a prospective study with a 13-year single-center experience

To prospectively evaluate the long-term clinical safety and efficacy of a newly designed self-expanding metallic stent (SEMS) in the treatment of patients with achalasia. Seventy-five patients with achalasia were treated with a temporary SEMS with a 30-mm diameter. The SEMSs were placed under fluoroscopic guidance and removed by gastroscopy 4–5 days after stent placement. Follow-up data focused on dysphagia score, technique and clinical success, clinical remissions and failures, and complications and was performed at 6 months, 1 year, and within 3 to 5 years, 5 to 8 years, 8 to 10 years, and >10 years postoperatively. Stent placement was technically successful in all patients. Complications included stent migration (n = 4, 5.33%), chest pain (n = 28, 38.7%), reflux (n = 15, 20%), and bleeding (n = 9, 12%). No perforation or 30-day mortality occurred. Clinical success was achieved in all patients 1 month after stent removal. The overall remission rates at 6 months, 1, 1–3, 3–5, 5–8, 8–10, and >10 year follow-up periods were 100%, 96%, 93.9%, 90.9%, 100%, 100%, and 83.3%, respectively. Stent treatment failed in six patients, and the overall remission rate in our series was 92%. The median and mean primary patencies were 2.8 ± 0.28 years (95% CI: 2.25–3.35) and 4.28 ± 0.40 years (95% CI: 3.51–5.05), respectively. The use of temporary SEMSs with 30-mm diameter proved to be a safe and effective approach for managing achalasia with a long-term satisfactory clinical remission rate

On transmission scheduling for wireless networks

In the 1990s Chlamtac and Farago introduced a transmission scheduling (TS) algorithm for wireless networks, called the (proper robust scheduling) PRS algorithm, later generalized to ML-PRS by Boztas to support a set of multipriority users, each with different transmission characteristics. More recently, this concept has been extended to TSMA (time spread multiple access) protocols-TDMA style protocols which are independent of network topology, subject to some global constraints, such as number of users, and maximum degree of the graph representing connectivity of the wireless network. We propose two improvements to TSMA protocols in this paper. The first one uses constant weight codes to reduce PRS framelength. The second one uses the coset structure of Galois fields to improve the ML-PRS algorithm by supporting more lower priority users for roughly comparable framelengt

Fast computation of Boolean influences

We introduce a fast spectral algorithm for computing influences of variables for Boolean functions. The influence of variables, as defined in computer science has close relationships with some criteria used in cryptographic evaluation of boolean functions, especially resilience. Our spectral algorithm can also be utilized to compute the resilience of Boolean functions. The algorithm is also of independent interest as a generalization of the Walsh-Hadamard transform

On renyi entropies and their applications to guessing attacks in cryptography

We consider single and multiple attacker scenarios in guessing and obtain bounds on various success parameters in terms of Renyi entropies. We also obtain a new derivation of the union bound. key words: guessing, Renyi entropy, Shannon entropy, predictability, brute force attacks, cryptography, work factor

Oblivious distributed guessing

We consider the oblivious distributed guessing of a random variable in three scenarios (single guessor, single constrained guessor, multiple guessors). The optimal guessing schemes in each case are obtained by means of a probability distribution which the guessor(s) use in order to determine their sequence of guesses. Some of the optimal distributions obtained have links to Rényi's generalization of Shannon's entropy, while one of them is related to the r th power means from mathematical analysis