In theory yes. In practice no, because cryptographic hashes are designed to make this as hard as possible. AFAIK you cannot prove that they are secure, so it mi

In theory yes. In practice no, because cryptographic hashes are designed to make this as hard as possible. AFAIK you cannot prove that they are secure, so it might be possible that known hashes can be broken entirely by using some breakthrough techniques of cryptanalysis. There is currently not much reason to believe such techniques exist, except perhaps for persistent rumors that the NSA is running some computationally very extensive operations (maybe with custom-built chips) that might be put to use for direct attacks on some weaker cryptographic algorithms like 2DES, RC4, SHA1, or 1024 bit RSA. That's pure speculation, though.