Is it possible to be sure of the uniqueness of a hash value in all cases?

It is impossible to be absolutely certain of the uniqueness of a hash value in all cases. Hash functions transform data into a fixed length, and with a large volume of input data, collisions are inevitable — different data can have the same hash. In Python, for example, the hash() function returns an integer, but its size and behavior can depend on the version and platform.

For critically important tasks where high uniqueness is required, cryptographic hash functions (such as SHA-256) are used, which significantly reduce the probability of collisions but do not eliminate it entirely.

Example of using hashlib for SHA-256:

import hashlib

text = "example string"
hash_object = hashlib.sha256(text.encode())
hex_dig = hash_object.hexdigest()
print(hex_dig)

Thus, the uniqueness of a hash value is a matter of probability, not a guarantee.