  We present a methodology for synchronization of chaotic oscillators with
linear feedback control. The proposed method is based on analyzing the chaotic
oscillator as a multi-mode linear system and deriving sufficient conditions for
asymptotic stability. The oscillators are synchronized in a master-slave
configuration, wherein a subset of the state variables for implementing the
feedback control, enabling applications in cryptography for message encryption
using the unused chaotic state variables. Controller stability is ensured
through conventional root-locus technique for designing appropriate loop gain.
We validate the methodology presented here with numerical simulations and
experimental results obtained using an operational amplifier (op-amp) based
electronic chaotic oscillator circuit.
