While it&#x27;s rare, do remember that hash collisions need to be thought of in birthday-paradox terms, which does increase the chance of observing a collision significantly. Hitting MD5&#x27;s birthday point (50% chance of collision) requires a couple tens of quintillions of hashes, but that&#x27;s probably a lot smaller number than people expect, and a not-unreasonable number to see in a sufficiently large-scale data archiving system.<p>(meanwhile there&#x27;s stuff in the wild using things like Java hashCode() to determine identities, and the birthday point on that is only around 75k IIRC)