[aeijdenberg]

Not quite as simple as a cryptographic hash alone - remember that if the set of possible inputs can be easily enumerated, then it's trivial to find the input data by brute force.

There are ways to work around this, for example objecthash[0] describes a small modification that prepends the input data with 32 bytes of random data before hashing in order to prevent this.

[0] https://github.com/benlaurie/objecthash#redactability

[randaouser]

yes precisely, you must include a random value that remains secret until the appropriate reveal time.