Digital holography can process whole object information in a generic manner. We discuss a data security application in the context of digital holography and generalize the full intensity or full phase encryption to complex information encryption. A double random phase encoding (DRPE) of the complex information in free-space propagation is performed to secure holographic data. Non-phase-shifting two-intensity measurements have been used to obtain a dc- and twin-image-free decryption of a complex object field without phase shifting errors. This method can also be used to secure digital data in a virtual optics mode using holographic principles, thus preserving the optical degrees of encoding freedom in the digital domain. We highlight the issues of whole information security using digital holographic means by carrying out simulation studies to show the proof of the concept. © 2008 Society of Photo Optical Instrumentation Engineers.