Secret Sharing using Image Hashing

This paper presents a cryptographic technique that encrypts secret information using a coding image by transforming the pixels of this image from the intensity domain to the characters domain using a hash function. In the proposed technique, the coding image will be used to encrypt the secret information at the sender and decrypt it at the receiver using the pixels whose intensity values are transformed to characters. A matrix of characters corresponding to the coding image is generated where each character in this matrix corresponds to a pixel in the coding image and each character in the secret information is mapped to a character in the matrix of characters. The locations of characters in the matrix of characters that correspond to pixels in the coding image and correspond to characters in the secret information forms the pixels map. The pixels map is encrypted using a secret key before being sent to the receiver on a secure communication channel different from that used to send the coding image and at different times. Upon receiving the coding image and the encrypted pixels map the receiver uses the secret key to decrypt the pixels map and uses the coding image and the hash function to generate the matrix of characters. Each location in the pixels map is used to retrieve a character from the matrix of characters in order to decrypt the secret information. Experimental results showed the effectiveness and the efficiency of the proposed algorithm where a message was encrypted using a coding image without modifying its pixels and it was decrypted without errors.