Let say I have a large file that is of considerable interest to the public and I want to publish it. The plan is to hash it using reliable function and publish its hash on a public blockchain (btc or eth) to timestamp it. Then, encrypt it asymmetrically and share copies to journalist around the world. When the time comes, I drop the public key and the cat's out. BUT! Opposition to the dissemination is the most technically powerful actor in the world whose strategy is to edit file to prove it an unreliable forgery and to do that - edited version needs to have the same hash. And they have an edge to do it - the file does contain amount of redundant data that may be changed without affecting underlaying functionality.
Let set a scene. Imaging that I have a 4K video file of a president of a powerful country murdering former secretary of state. The face of the president is seen in only few seconds of a few minutes of video, but would prove damning nonetheless. Its secret spying agency ASN is set to edit the video by planting my face on the murderor's body thus turning tables. Let say that the rehashing effort is of order of billion dollars worth of hashing power of entire bitcoin mining community. If a doctored version with correct hash is produced, my proof would not qualify as beyond the reasonable doubt and the pres walks away.
Ok, I am playing here, but I hope you get my question. How to cryptographically protect integrity of a file that has some redundancy whose fiddling may cover for functional changes? Or, in another words, is there a modern hash functions powerful enough to protect integrity even against available nonce to make editing unfeasible today?