... of giving you the actual key, it gives you a safe containing the key. This approach allows the hash latch to protect itself from forged keys and also enables you to put the same key into multiple safes without the recipients of these safes knowing they have the same key (even if they compare their ciphertexts).
Moreover, the hash latch verifies the integrity of a key after decrypting it (just in case).
You can read the tutorial about it on Instructables: https://www.instructables.com/Hash-Latch/