Abstract: [Purposes] Addressing the current lack of robust watermarking algorithms suitable for remote sensing image data in multi-party collaboration scenarios,this paper proposes a secure multi-party watermarking algorithm for remote sensing image data based on secret sharing and DCT-QIM. [Methods] The algorithm first scrambles the original data in blocks,then uses additive secret sharing to divide the image into multiple encrypted shares,which are distributed to different collaborating parties.Each collaborator independently performs quantization index modulation watermark embedding on their respective shares in the discrete cosine transform domain.After collecting all watermarked shares,the watermarked image is reconstructed through additive reconstruction. [Findings] Experimental results show that the peak signal-to-noise ratio of the watermarked image reaches 50.126 dB and the structural similarity index is 0.999,indicating minimal impact on visual quality.The embedded watermark can be successfully extracted under various attacks,including cropping,rotation,Gaussian noise,and JPEG compression,demonstrating strong robustness.Furthermore,incomplete shares held by any single party cannot reveal any meaningful information about the original image,and such incomplete shares also prevent any individual party from privately verifying,tampering with,or forging watermark credentials,thereby effectively ensuring data privacy and security throughout the multi-party collaboration process. [Conclusions] The proposed algorithm enables secure collaborative multi-party watermark embedding while preserving the privacy of remote sensing image data,providing technical support for copyright protection in multi-party collaboration scenarios involving remote sensing image data.

Key words: remote sensing image, digital watermark, secret sharing, discrete cosine transform, quantized index modulation