Depth of the SHA-256 collision search knowing partial input and final hashes So I have a partial input data (string) PART1+UNKNOWN+PART2, length of UNKNOWN is self-describing.
I have a bunch of valid hashes (about 8 or so) that are compatible.
My question is then: will bruteforce search for full collision given the data at hand be as long?
Yes, but please note that the question/answers you are pointing to are about partial collisions on the output, not partial input. Finding a full hash collision is not computationally feasible for hash functions that are considered secure, such as SHA-256.