On the secure model of multimedia hashing

Robust multimedia hash is widely used in database search, digital watermark and multimedia authentication. A multimedia hash is a randomized compact representation of multimedia content. In applications, the security issue is particularly important. We measure the security level of multimedia hashing from the Shannon´s unicity distance. Using a recently proposed video-hashing scheme as representation, we analyze quantitatively the security of the scheme. Some analyses show that the secret hashing key can be estimated when reused number of the key exceed the calculated unicity distance.