Do any methods exist whereby a "hash" can be embedded in the "document" it hashes?
What I mean is this. Say I have a given plaintext T. I wonder if there is a method to craft (i.e. not discover as a fluke) a "document" D being some combination (e.g. a concatenation) of T and a hashvalue h, where h is H(D), H being some hash function.
Perhaps a simpler way of phrasing this is: Is there any way to make a document contain its own hash, under the constraint that the document must, apart from its own hash, contain a given plaintext?
Is this possible in theory? In practice?
This question is somewhat different from this one, in that I am assuming a given plaintext T, whereas that question asks if any T can be crafted (or found).