Photoluminescent soft materials have been widely applied in sensing, display devices, and organic light-emitting diodes, [1] and also have received great attention toward security protection applications in information storage, date recording and encryption. [2] In particular, luminescent hydrogel-based 3D codes prepared in environmentally friendly process could not only increase the information density per unit area but also be employed as wearable or biological anti-counterfeiting materials. [3] On the other hand, the information recorded directly in these materials is usually visible under either ambient or UV light, which would hamper their practical applications in confidential information protection because these anti-counterfeiting labels could be easily mimicked. [4] In this context, smart luminescent materials that can perceive the surrounding stimuli and respond to them should be ideal for confidential information protection. [5] Under external stimuli, the luminescent outputs of these materials can be precisely modulated, preventing the information from being stolen or mimicked. [6,7] Stimulus-responsive luminescent materials that rely on constant addition of chemicals have been developed for information encryption and decryption. [8] Since these methods require invasive stimuli, it may be difficult for consumers without professional chemistry knowledge to handle the encoded information by adding chemicals. Therefore, it is highly desirable to develop alternative switchable luminescent materials with confidential encryption property capable of being easily operated in a noninvasive manner, where the security codes are initially invisible and become visible under specific external stimuli. In this way, reversible information encryption and decryption could be achieved. Light irradiation is an appealing external stimulus because it provides clean, spatiotemporal, and noninvasive control on the operation with high precision, [9] showing greater convenience in activating or erasing the code information as compared to other chemical stimuli. [10] In terms of emitting sources, lanthanide complexes are excellent emitting centers because of their intriguing optical properties, such as narrow emission bands, large Stokes shift, high luminescent efficiency, and long luminescence lifetime. [7,11] To the best of our knowledge, however, achieving Conventional luminescent information is usually visible under either ambient or UV light, hampering their potential application in smart confidential information protection. In order to address this challenge, herein, light-triggered luminescence ON-OFF switchable hybrid hydrogels are successfully constructed through in situ copolymerization of acrylamide, lanthanide complex, and diarylethene photochromic unit. The open-close behavior of the diarylethene ring in the polymer could be controlled by UV and visible light irradiation, where the close form of the ring features fluorescence resonance energy transfer with the lanthanide complex. The hydrogel-based block...