Traditional cryptographic hashes such as SHA-1 and MD5 produce uniformly distributed (or perfectly randomized) hash values. They are not applicable in the aforementioned multimedia applications because they are extremely sensitive to the message being hashed; i.e., even a one bit change in the input (media) will change the output hash dramatically. Likewise, content-based feature extraction methods, developed from a signal processing perspective, are known to be robust but not secure. The ultimate goal of secure media hashing research is to make the job of an adversary computationally infeasible; i.e., it should be nearly impossible for a malicious attacker to come up with ways to tamper the image content (in a reasonable amount of time) and defeat the authentication scheme.
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