While discussing maximum password lengths, a poster made this comment:
The longer the allowed input, the easier to supply an input that could cause a hash collision
To explain (since the lack of context might make the statement unclear), the poster is stating that it is easier to find a hash collision for a longer password than for a shorter one. I had not heard this before, and now I'm curious. My own (admittedly naive) expectation is that the collision probability should be fairly independent of message size since collisions happen in digest space, and the digest is fixed length.
What pieces of the puzzle am I missing? Does the ease of finding a collision depend on input length?