In this paper a new patch-based digital signature (DS) is suggested. The proposed approach similar to steganography methods hides the secure message in a host image. However, it uses a patch-based key to code/decode the data like cryptography approaches. Both the host image and key patches are randomly initialized. The proposed approach consists of coding and decoding algorithms. The coding algorithm converts the characters stream of the secret message to the patches stream of the DS image. The final image can be further distorted by noise to hide the source patches. Nevertheless, the decoding algorithm uses the connectivity and compactness properties of patches to decode the secret message. Experimental results demonstrated that it is significantly robust against noise. The proposed approach has been successfully used for digital signature generation.

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