Encryption of ghost imaging

We propose an approach for the optical encryption of ghost images reconstructed from the spatially correlated classical two-beam pairs. This approach has the capability of encrypting ghost images by flexibly manipulating the position correlation of a pair of ``signal'' and ``idler'' beams. We experimentally demonstrate that the perfect ghost image can be extracted by decrypting the encrypted information of an object, in particular, our approach under eavesdropping has a higher security for encryption compared with previous approaches.