We introduce the notion of key stretching, a mechanism to convert short s-bit keys into longer keys, such that the complexity required to brute-force search a s+ t-bit keyspace is the same as the time required to brute-force search a s-bit key stretched by t bits.

OBJECTIVES The purpose of this study was to examine the effects of the use of a vapocoolant blend of pentafluoropropane and tetrafluoroethane (Gebauer's Spray and Stretch) on hip flexion stretching. METHODS Thirty volunteers were randomly assigned to spray and stretch treatment and stretch only control groups. Each group was assessed pre- and posttest on passive and active hip flexion range o...

Tomographic particle image velocimetry measurements of homogeneous isotropic turbulence that have been made in a large mixing tank facility at Cambridge are analysed in order to characterize thin highly sheared regions that have been observed. The results indicate that such regions coincide with regions of high enstrophy, dissipation and stretching. Large velocity jumps are observed across the ...

Motivated by the redrawing of hot glass into thin sheets, we investigate the shape and stability of a thin viscous sheet that is inhomogeneously stretched in an imposed nonuniform temperature field. We first determine the associated base flow by solving the long-time-scale stretching flow of a flat sheet as a function of two dimensionless parameters: the normalized stretching velocity α and a d...

The self similar steady boundary layer flow induced by a permeable continuous surface stretching with velocity Uw (X) = A. x −1/2 in a quiescent incompressible fluid in the presence of a transverse magnetic field of uniform strength Bo, with suction velocity Vw(x) = − ( υA 4 ) 1/2 . xfw is considered. Numerical solution of the resulting similarity momentum equation using Runge-Kutta-Fehlberg Fo...

We study the scaling properties of randomly folded aluminum sheets of different thicknesses h and widths L . We found that the fractal dimension D=2.30+/-0.01 and the force scaling exponent delta=0.21+/-0.02 are independent of the sheet thickness and close to those obtained in numerical simulations with a coarse-grained model of triangulated self-avoiding surfaces with bending and stretching ri...

The relaxation dynamics of a rubbed polystyrene (PS) surface have been characterized using infrared-visible sum frequency generation spectroscopy (SFG). The SFG results were compared with previous relaxation of retardation measurements, and the results show that the rubbed PS surface has the same T(g) as the bulk where T(g) is defined as tau(T(g))=5 s, however, the surface has a lower activatio...

Methylation of cytosine is a covalent modification of DNA that can be used to silence genes, orchestrating a myriad of biological processes including cancer. We have discovered that a synthetic nanopore in a membrane comparable in thickness to a protein binding site can be used to detect methylation. We observe a voltage threshold for permeation of methylated DNA through a <2 nm diameter pore, ...