  Under discussion in the paper is an $i\mathcal{O}$ (indistinguishability
obfuscator) for circuits in Nick's Class. The obfuscator is constructed by
encoding the Branching Program given by Barrington's theorem using Multilinear
Jigsaw Puzzle framework. We will show under various indistinguishability
hardness assumptions, the constructed obfuscator is an $i\mathcal{O}$ for
Nick's Class. Using Fully Homomorphic Encryption, we will amplify the result
and construct an $i\mathcal{O}$ for $\textbf{P}/poly$, which are circuits of
polynomial size. Discussion on $i\mathcal{O}$ and Functional Encryption is also
included in this paper.
