We report a method of simultaneous compression and encryption of multiple images based on a specific spectral fusion. This method is able to manipulate target images with close spectral characteristics. For that purpose, we introduce an optimized algorithm for the task of simultaneously compressing and encrypting phase-shifting digital holograms (PSIDH) for three-dimensional object reconstruction. This technique is based on a spectral fusion, without overlapping, of interference patterns I corresponding to phase shifts. We first divide the spectral plane into several areas and optimize the bandwidth of the spectral domain. Each area is affected to a spectrum of an intensity pattern IPSIDH. A two-level encryption of these patterns is realized. First, we apply a discrete cosine transform (DCT) spectral fusion after addition of an input key image. Then, each DCT-spectral interference pattern is multiplied with a specific random intensity function to uniformly distribute the spectral intensity. To validate our approach, many numerical simulations are performed. The simplicity and robustness of our tests make this algorithm appealing for object reconstruction.