Playfair Cipher 1.not even the large number of keys in a monoalphabetic cipher provides security 2.one approach to improving security was to encrypt multiple letters 3.the Playfair Cipher is an example 4.invented by Charles Wheatstone in 1854

Cubic spline algorithm approximating function y=f(x) - ((-2)*x*(2*x+3))/(x*x+4*x+5) in interval [-2 2]-Cubic spline algorithm approximating function y=f(x)- ((-2)*x*(2*x+3))/(x*x+4*x+5) in interval [-2 2]

基于U盘的强身份认证，附VB源码及dll接口说明-U disk-based strong authentication, with VB source code and dll interface descr iption

Cryptographic Hash Functions: A cryptographic hash function must have at least two security properties: collision free and Hiding. Collision free property ensures that for a given function H, no one can find x and y such that H(x) = H(y). The hid