This paper proposes a highly secure image watermarking and digital signature algorithm based on ECC and MIRACL,the former is on the basis of ECDLP very difficult to solve,and the latter implements all kinds of the primitives necessary to various arithmetical operation of big integer and fraction with multiprecision.Meanwhile,this paper is combining with the effective theory and practice of SVD and DSWT.Theoretical analysis and experimental results show that the algorithm in the paper is more secure and practical to protect the copyrights of multimedia data works.