  In this letter we consider a prototype model which is described as an
autonomous continuous time delayed differential equation with just one
variable. The chaos has been investigated with variable delay time and the
synchronization phenomenon is examined both numerically and analytically using
the Krasovskii-Lyapunov functions. We have applied adaptive coupling law for
synchronization,where the coupling equation also contains delay with modulated
time. We also studied the effect of cryptography for this coupled system and
the message extraction procedure is illustrated with the help of simulated
results.
