<p>Computational ghost imaging (CGI) is an imaging technique that uses the second-order correlation properties of optical fields. It uses random illumination patterns to illuminate the object, collects the signal via a single-pixel bucket detector, and later reconstructs an image of the object. By treating the illumination patterns as keys and the bucket measurements as ciphertexts, CGI can be regarded as an encryption process. This paper proposes a multi-party collaborative decryption scheme based on CGI, which aims to reduce key transmission data whilst enabling cooperative decryption among multiple users and verifying the legitimacy of the ciphertext source via digital watermarking. This method uses a chaotic system to generate a measurement matrix, and only the chaotic parameter needs transmission. The receiver can reconstruct the measurement matrix, thereby reducing the amount of key transmission. Further, verifiable secret sharing (VSS) is employed to divide the chaotic parameter into multiple shares, which are then distributed to different recipients. Decryption is only feasible when a threshold number of recipients collaborate to reconstruct the chaotic parameter. To further improve security, hashed identity information is embedded into the ciphertext as a watermark, enabling confirmation of the ciphertext’s origin. Experimental results show the feasibility of the proposed scheme and its ability to resist tampering, offering a new approach to secure multi-user communication.</p>