Cryptography is the scheme that is used to encrypt a simple text. It hides the meaning of the message. It pays an important role in security over a network. In this paper, the authors present a cryptography system that is based on the Sphere (a shape in mathematics). Sphere is locus of point in space which moves in such a way that its distance from fixed point always remain constant, where fixed point is the center of the sphere and constant distance is the radius of sphere. They used the sphere concept for implementing the asymmetric cryptography. In this system public key and private key are generated by using the property of Sphere.