10 research outputs found
Can a graft be placed over a flap in complex hypospadias surgery? An experimental study in rabbits
System-on-Chip solution for cryptanalysis of elliptic curve based ciphers
W pracy zaprezentowano system typu SoC (System-on-Chip) zrealizowany w układach FPGA wspomagający obliczenia pozwalające na złamanie szyfru opartego na krzywych eliptycznych. Do ataku kryptoanalitycznego wykorzystano algorytm rho Pollarda. System zbudowany jest ze sprzętowych jednostek obliczeniowych HardRho pracujących pod kontrolą procesora NiosII i wykorzystuje interfejs Ethernet do komunikacji zewnętrznej. Omówiona została koncepcja budowy rozproszonego systemu obliczeniowego składającego się z jednostek obliczeniowych będących systemami typu SoC.Public-key cryptosystems allow secure connections and data exchange through unsafe communication channel without the need of a previous secure key exchange. One of popular cryptosystems used nowadays is Elliptic Curve Cryptosystems (ECC). Cryptanalytic attack on ECC system involves solving the Elliptic Curve Discrete Logarithm Prob-lem (ECDLP). The best known algorithm used to solve ECDLP is Pollard's rho method. So far successful attacks on ECC systems have mostly been based on distributed computer networks. In this paper a hardware cryptanalytic system is presented. The system is implemented in FPGA devices and performs computations of rho Pollard's algorithm. System is based on SoC solution (System-on-Chip) and works under control of a central server in order to form a greater distributed computing system. In the first paragraph of this paper there are presented the aim of work as well as the reasons for choosing FPGA devices and SoC solution. The second paragraph gives the theoretical background [3, 4, 5], explains the basic terms and presents the rho Pollard's algorithm [6, 7]. The third paragraph describes HardRho computation unit HardRho hardware (Fig. 1) and shows differences between the current and recent unit version of unit described in [8, 9]). The fourth paragraph of the paper deals with the SoC solution composed of several HardRho units, NiosII processor and Ethernet communication interface. The system structure (Fig. 2) and internal components [11, 12] are presented. The fifth paragraph is nfocused on the results of implementation and the estimated time of cryptanalysis of an elliptic curve ECC2-89 [1] (Tab. 1). The HardRho unit and [13] are compared (Tab. 2). The obtained results suggest high efficiency of the presented SoC solution. The future investigations and possible optimisation of the system are discussed
Quality assurance study of bacterial antigen testing of cerebrospinal fluid.
Bacterial antigen testing (BAT) of cerebrospinal fluid (CSF) by latex agglutination is a low-yield procedure in patients whose CSF specimens have normal laboratory parameters. Between August 1992 and August 1994, we evaluated 287 bacterial antigen (BA) test requests to determine whether yields could be improved and whether patient costs could be reduced by cancelling BAT for those patients with normal CSF parameters (cell count, protein, glucose) after consultation with physicians. A total of 171 (68%) BA tests were canceled by this approach. None of these CSF specimens was culture positive for an organism detectable by BAT. Of the remaining 116 CSF specimens tested, only 3 were positive by BAT, one each for Neisseria meningitidis, Streptococcus pneumoniae, and group B streptococcus. Only 43 of the CSF specimens tested had at least two abnormal parameters; the 3 positive CSF specimens were included in this group. In light of the low rate of positivity, the number of BA tests can be further reduced by establishing criteria that must be met before a CSF specimen is accepted for BAT. After review of our data and the literature concerning this topic, we concluded that only specimens with leukocyte counts of > or = 50 cells per mm3 should be tested. Of 287 specimens evaluated in our study, only 36 met this criterion, including the 3 BA-positive specimens. Enacting such a restriction would have reduced the total number of BA tests by 251 (87%) without compromising patient care. A laboratory cost savings of $6,500 per year would have been realized, with a substantial reduction in the cost per positive test.(ABSTRACT TRUNCATED AT 250 WORDS