Abstract: In this paper, a novel image encryption scheme with the capability of checking
integrity based on inverse matrix is proposed for image security by utilizing combinatorial theory.
A fragile and noised cipher-image is yielded by applying this scheme to grey-level image.
Decryption is a simple reversed process of encryption. The integrity of cipher-image can be
checked by human visual system without any complicated computations. When the cipher-image
is tempered, we cannot gain any information about the secret image except a noised image. The
key is simple and large enough. Theoretical analysis and experimental results demonstrate that the
proposed scheme offers a high secure and effective mechanism for image encryption.

Key words: modal M inverse matrix, digital image encryption algorithm, capability of
checking integrity, fragile cipher-image