I will survey Gentry's acclaimed fully homomorphic encryption scheme. A homomorphic encryption is a form of encryption performing some specific algebraic operation on ciphertexts implicitly performs some specific algebraic operation on the corresponding ciphertexts. Gentry's scheme allows one to homomorphically apply any algebraic function on the plaintexts. This had been an open for more than 30 years and was considered the ‘holy grail’ of cryptography. Gentry's scheme relies on lattices corresponding to ideals in number fields, and its security relies (in part) on solving a variant of the closest vector problem for these lattices.