Cryptographic Divergences: New Techniques and New Applications

In the recent years, some security proofs in cryptography have known significant improvements by replacing the statistical distance with alternative divergences. We continue this line of research, both at a theoretical and practical level. On the theory side, we propose a new cryptographic divergence with quirky properties. On the practical side, we propose new applications of alternative divergences: circuit-private FHE and prime number generators. More precisely, we provide the first formal security proof of the prime number generator PRIMEINC (Brandt and Damgård, CRYPTO 1992), and improve by an order of magnitude the efficiency of a prime number generator by Fouque and Tibouchi (ICALP 2014) and the washing machine technique by Ducas and Stehlé (EUROCRYPT 2016) for circuit-private FHE

Amplifying the Security of Functional Encryption, Unconditionally

Security amplification is a fundamental problem in cryptography. In this work, we study security amplification for functional encryption (FE). We show two main results: 1) For any constant epsilon in (0,1), we can amplify any FE scheme for P/poly which is epsilon-secure against all polynomial sized adversaries to a fully secure FE scheme for P/poly, unconditionally. 2) For any constant epsilon in (0,1), we can amplify any FE scheme for P/poly which is epsilon-secure against subexponential sized adversaries to a fully subexponentially secure FE scheme for P/poly, unconditionally. Furthermore, both of our amplification results preserve compactness of the underlying FE scheme. Previously, amplification results for FE were only known assuming subexponentially secure LWE. Along the way, we introduce a new form of homomorphic secret sharing called set homomorphic secret sharing that may be of independent interest. Additionally, we introduce a new technique, which allows one to argue security amplification of nested primitives, and prove a general theorem that can be used to analyze the security amplification of parallel repetitions

The role of c-Myc protooncogene in chronic myelogenous leukemia.

c-Myc transcriptional factor encoded by c-myc protooncogene plays an important role in the regulation of cell cycle. It was also established that c-Myc is important for the transformation of fibroblasts and murine bone marrow cells induced by BCR/ABL tyrosine kinase encoded by bcr/abl oncogene localized on Philadelphia-chromosome (Ph1). The role of c-Myc in the proliferation of the leukemic cells was not known. Therefore, we examined the effect of c-Myc protein downregulation, using antisense oligodeoxynucleotides, on the growth of the BCR/ABL- dependent cell line and chronic myelogenous leukemia (CML) patients cells. Downregulation of c-Myc expression caused complete inhibition of the proliferation of BCR/ABL-dependent BV173 cell line and 50-70% inhibition of the colony formation of CML cells. These results suggests that c-Myc cooperates with BCR/ABL and is necessary for the growth of Ph1-positive leukemias

The diverse effect of topoisomerase I specific inhibitor (camptothecin) on normal and BCR/ABL-dependent hematopoietic cells proliferation: therapeutic implications.

Camptothecin (CPT), a specific topoisomerase I inhibitor, in the presence of hematopoietic growth factors exerted an antiproliferative effect against normal bone marrow cells (NBMC) as well as chronic myelogenous leukemia-chronic phase (CML-CP) and blast crisis (CML-BC) cells. In the absence of growth factors, however, only the colony formation by CML-BC cells was inhibited by CPT, leaving NBMC and CML-CP cells intact or much less affected. Analysis of the cellular DNA content revealed that CPT induced specific changes in cell cycle distribution: decrease in S and G2/M fraction with simultaneous accumulation of the cells in G1 phase and the appearance of "sub-diploid" (apoptotic) peak. To determine if CPT is able to exert selective antileukemic effect, 1:1 mixture of NBMC and CML-BC cells was exposed to CPT in the absence of growth factors and assayed for growth ability in clonogenic assay and for expression of BCR/ABL transcript in single colonies. BCR/ABL transcript was not detected in colonies incubated with CTP, in contrast, most of colonies arising from untreated cells possessed leukemic origin (BCR/ABL expression). Our results indicate that CPT is selectively effective in vitro against the leukemia cells. This offers the prospect of a novel and more selective treatment of CML

Location and Incidence Rate of Anastomotic Aneurysms – own Clinical Material and Literature Review

Anastomotic aneurysms occurs at various levels of arterial system. Determining their location and incidence rate required investigation of large patient clinical material. Material and methods. In the years 1989-2010 in local centre 230 anastomotic aneurysms were operated in 180 patients. Results. For 187 (81.3%) patients anastomotic aneurysms were localised in the groin, while for remaining 43 (18.7%) they occurred in other localisations. In aortic arch branch they occurred four times (1.7), in descending aorta - three times (1.3%), in abdominal aorta - 14 (6.1%) and in iliac arteries - 6 (2.6%). While for anastomosis with popliteal artery they were diagnosed in 16 (7%) patients. Own clinical material was compared with literature data. Conclusions. Anastomotic aneurysms in over 80% of cases occur in the groin, remaining percentage corresponds to other localisations

Anastomotic aneurysms- 20-years of experience from one center

Anastomotic aneurysms may develop after any type of vascular surgery, in different areas of the arterial system, and require reoperation. The frequency of occurrence of the above-mentioned is estimated at 1-5%. Material and methods. During the period between 1989 and 2010, 180 patients with 230 anastomotic aneurysms were subject to surgical intervention at the Department of General and Thoracic Surgery, Warsaw Medical University. The study group comprised 21 (11.7%) female and 159 (88.3%) male patients, aged between 30 and 87 years (mean age - 62.8 years). In relation to the number of anastomoses aneurysms were diagnosed in 2.1% of cases. Twenty-four (10.4%) patients were diagnosed with recurrent aneurysms. Results. Surgical procedures performed were as follows: artificial prosthesis implantation (119), reanastomosis (40), patch plasty (25), graftectomy (19), prosthesis replacement (9), and stent-graft (7) implantation. 195 (84.8%) aneurysms were subject to planned surgery, while 35 (15.2%) required emergency intervention. 77.8% of patients were diagnosed with aseptic aneurysms, while the remaining 22.2% with infected perioperative aneurysms. Good treatment results were obtained in 149 (82.8%) patients. Limb amputations were performed in 19 (10.5%) cases. Twelve (6.7%) patients died as a consequence of infection and general complications. Conclusions. Vascular reoperations are a difficult clinical problem and are burdened with a high rate of complications. The above-mentioned often require complex treatment, in order to improve therapeutic results

The influence of phosphorothioate oligodeoxynucleotides on various organs in vivo.

To characterize the distribution and toxicity of phosphorothioate antisense oligodeoxynucleotides ([S]ODNs) in vivo, the mice, previously injected with BV173 leukemic cells (Philadelphia chromosome-positive chronic myeloid leukemia blast-crisis), received intravenously 26-mer BCR-ABL antisense oligodeoxynucleotides (1 mg/mouse/day) for 9 consecutive days. Our investigation revealed that [S]ODNs were distributed to almost all organs except the brain with the highest level in the liver, spleen and kidneys. They were also detected in CD10+ leukemic cells isolated from spleen and bone marrow. Intracellular distribution assay showed the presence of [S]ODNs most prominently in nuclear and cytoplasmic fractions. Our data demonstrated no significant toxicity of [S]ODNs except the increase in spleen weight