This work describes a digital holographic encryption technique based on programmable double key masks configuration. The double key masks are designed and implemented by using electrically addressed liquid crystal spatial light modulators operated at phase modulation mode. The architecture of four-step phase-shifting digital holography is used to generate the double key holograms for implementing the encryption and decryption. Both simulation and experimental results show that the feasibility of the digital holographic encryption system with double key masks in the Fourier or Fresnel domains for performing high-data-security properties and security enhancement. The proposed encryption system with electrically-addressed spatial light modulators provides the flexibility of key mask design by on-line processing.